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Giles JB, Rollin J, Martinez KL, Selleng K, Thiele T, Pouplard C, Sheppard JAI, Heddle NM, Phillips EJ, Roden DM, Gruel Y, Warkentin TE, Greinacher A, Karnes JH. Laboratory and demographic predictors of functional assay positive status in suspected heparin-induced thrombocytopenia: A multicenter retrospective cohort study. Thromb Res 2023; 229:198-208. [PMID: 37541168 PMCID: PMC10528503 DOI: 10.1016/j.thromres.2023.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/16/2023] [Accepted: 07/18/2023] [Indexed: 08/06/2023]
Abstract
Heparin-induced thrombocytopenia (HIT) is an antibody-mediated immune response against platelet factor 4 (PF4) bound to heparin anticoagulants. A priori identification of patients at-risk for HIT remains elusive and a number of risk factors have been identified, but these associations and their effect sizes have limited validation in large cohorts of suspected HIT patients. The aim of this study was to investigate existing anti-PF4/heparin antibody thresholds and model the relationship of demographic variables and anti-PF4/heparin antibody levels with functional assay positivity across multiple institutions in the absence of detailed clinical data. In a large collection of suspected HIT patients (n = 8904), we tested for associations between laboratory and demographic variables and functional assay positive status as well as anti-PF4/heparin antibody levels. We also tested for correlation between IgG-specific and polyspecific (IgG/IgA/IgM) anti-PF4/heparin antibody values and their ability to predict functional assay positive status using area under the receiver operating characteristic (AUROC). Logistic regression identified increasing anti-PF4/heparin antibody OD levels (OR = 51.84 [37.27-74.34], p < 2.0 × 10-16) and female sex (OR = 1.47 [1.19-1.82], p = 3.5 × 10-4) as risk factors for positive functional assay in the largest cohort with consistent effect sizes in two other cohorts. In a subset of 1175 patients, polyspecific and IgG-specific anti-PF4/heparin antibody values were heterogeneous (mean coefficient of variation = 31.9 %), but strongly correlated (rho = 0.878; p < 2 × 10-16) with similar prediction of functional assay positivity (polyspecific AUROC = 0.976 and IgG-specific AUROC = 0.980). Thus, we recapitulate previously identified risk factors of functional assay positivity, providing precise effect sizes in a large observational population of suspected HIT patients. Our data reinforce the necessity of functional assay confirmation and suggest that, despite heterogeneity, polyspecific and IgG-specific anti-PF4/heparin antibody assays predict functional assay positive status similarly, even in the absence of 4Ts scores and detailed clinical data.
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Affiliation(s)
- Jason B Giles
- Department of Pharmacy Practice and Science, University of Arizona R. Ken Coit College of Pharmacy, Tucson, AZ, USA
| | - Jerome Rollin
- Regional University Hospital Centre Tours, Department of Hemostasis, Tours, France; University of Tours, EA4245, T2i, Tours, France
| | - Kiana L Martinez
- Department of Pharmacy Practice and Science, University of Arizona R. Ken Coit College of Pharmacy, Tucson, AZ, USA
| | - Kathleen Selleng
- Institute of Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany
| | - Thomas Thiele
- Institute of Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany
| | - Claire Pouplard
- Regional University Hospital Centre Tours, Department of Hemostasis, Tours, France; University of Tours, EA4245, T2i, Tours, France
| | - Jo-Ann I Sheppard
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Nancy M Heddle
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Elizabeth J Phillips
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Dan M Roden
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yves Gruel
- Regional University Hospital Centre Tours, Department of Hemostasis, Tours, France; University of Tours, EA4245, T2i, Tours, France
| | - Theodore E Warkentin
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Andreas Greinacher
- Institute of Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany
| | - Jason H Karnes
- Department of Pharmacy Practice and Science, University of Arizona R. Ken Coit College of Pharmacy, Tucson, AZ, USA; Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN, USA.
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Erich BJ, Knutson J, Barnes BJ. Analysis of heparin-induced thrombocytopenia diagnostic and management strategies in individuals with inconclusive antibody optical densities. Blood Coagul Fibrinolysis 2023; 34:272-280. [PMID: 37115961 DOI: 10.1097/mbc.0000000000001220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
Heparin-induced thrombocytopenia (HIT) is an uncommon but serious complication of exposure to heparin. Antibody optical densities (ODs) used to diagnose HIT exceeding 2 are highly suggestive of disease, whereas ODs less than 0.5 often 'rule out' HIT. Variation in the clinical care of patients with inconclusive ODs between 0.5 and 2 is likely. This single-centre, retrospective analysis evaluates the diagnosis, management and outcomes of those with antibody ODs between 0.5 and 2. We queried our institution's Healthcare Enterprise Repository for Ontological Narration (HERON) database to identify individuals with antibody ODs between 0.5 and 2. Chart review was completed to calculate 4T scores, corroborate diagnosis codes with documented information in our electronic health record (EHR) and evaluate the diagnosis, management and outcomes of these individuals. These data were evaluated using descriptive and univariate statistics. Among individuals evaluated for HIT between November 2007 and July 2020, we identified 302 individuals with ODs between 0.5 and 2. Serotonin release assays (SRAs) were assessed in 55% (165/302) and were positive in 12% (20/165). In those with available data, 96% with low 4T scores had negative SRAs and 4% had positive SRAs. As 4T scores and antibody ODs proportionally increased, SRA positivity also increased. Clinical management varied widely; however, 4T scoring remains a valuable assessment in this cohort. In those with HIT antibody ODs between 0.5 and 2, true positives were uncommon, and their clinical management varied widely. Fortunately, 4T scoring is a useful prognostic tool that improves the diagnosis and management among those with inconclusive HIT.
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Affiliation(s)
| | - Jace Knutson
- Inpatient Pharmacy, The University of Kansas Health System
| | - Brian J Barnes
- School of Pharmacy, The University of Kansas Medical Center, Kansas City, Kansas, USA
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Nilius H, Cuker A, Haug S, Nakas C, Studt JD, Tsakiris DA, Greinacher A, Mendez A, Schmidt A, Wuillemin WA, Gerber B, Kremer Hovinga JA, Vishnu P, Graf L, Kashev A, Sznitman R, Bakchoul T, Nagler M. A machine-learning model for reducing misdiagnosis in heparin-induced thrombocytopenia: A prospective, multicenter, observational study. EClinicalMedicine 2023; 55:101745. [PMID: 36457646 PMCID: PMC9706528 DOI: 10.1016/j.eclinm.2022.101745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Diagnosing heparin-induced thrombocytopenia (HIT) at the bedside remains challenging, exposing a significant number of patients at risk of delayed diagnosis or overtreatment. We hypothesized that machine-learning algorithms could be utilized to develop a more accurate and user-friendly diagnostic tool that integrates diverse clinical and laboratory information and accounts for complex interactions. METHODS We conducted a prospective cohort study including 1393 patients with suspected HIT between 2018 and 2021 from 10 study centers. Detailed clinical information and laboratory data were collected, and various immunoassays were conducted. The washed platelet heparin-induced platelet activation assay (HIPA) served as the reference standard. FINDINGS HIPA diagnosed HIT in 119 patients (prevalence 8.5%). The feature selection process in the training dataset (75% of patients) yielded the following predictor variables: (1) immunoassay test result, (2) platelet nadir, (3) unfractionated heparin use, (4) CRP, (5) timing of thrombocytopenia, and (6) other causes of thrombocytopenia. The best performing models were a support vector machine in case of the chemiluminescent immunoassay (CLIA) and the ELISA, as well as a gradient boosting machine in particle-gel immunoassay (PaGIA). In the validation dataset (25% of patients), the AUROC of all models was 0.99 (95% CI: 0.97, 1.00). Compared to the currently recommended diagnostic algorithm (4Ts score, immunoassay), the numbers of false-negative patients were reduced from 12 to 6 (-50.0%; ELISA), 9 to 3 (-66.7%, PaGIA) and 14 to 5 (-64.3%; CLIA). The numbers of false-positive individuals were reduced from 87 to 61 (-29.8%; ELISA), 200 to 63 (-68.5%; PaGIA) and increased from 50 to 63 (+29.0%) for the CLIA. INTERPRETATION Our user-friendly machine-learning algorithm for the diagnosis of HIT (https://toradi-hit.org) was substantially more accurate than the currently recommended diagnostic algorithm. It has the potential to reduce delayed diagnosis and overtreatment in clinical practice. Future studies shall validate this model in wider settings. FUNDING Swiss National Science Foundation (SNSF), and International Society on Thrombosis and Haemostasis (ISTH).
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Affiliation(s)
- Henning Nilius
- Department of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Adam Cuker
- Department of Medicine and Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Sigve Haug
- Mathematical Institute, University of Bern, Bern, Switzerland
- Albert Einstein Center for Fundamental Physics and Laboratory for High Energy Physics, University of Bern, Bern, Switzerland
| | - Christos Nakas
- Department of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Laboratory of Biometry, School of Agriculture, University of Thessaly, Volos, Greece
| | - Jan-Dirk Studt
- Division of Medical Oncology and Hematology, University and University Hospital Zurich, Zurich, Switzerland
| | | | - Andreas Greinacher
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Adriana Mendez
- Department of Laboratory Medicine, Kantonsspital Aarau, Aarau, Switzerland
| | - Adrian Schmidt
- Clinic of Medical Oncology and Hematology, Municipal Hospital Zurich Triemli, Zurich, Switzerland
| | - Walter A. Wuillemin
- Division of Hematology and Central Hematology Laboratory, Cantonal Hospital of Lucerne and University of Bern, Switzerland
| | - Bernhard Gerber
- Clinic of Hematology, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland
| | - Johanna A. Kremer Hovinga
- Department of Hematology and Central Hematology Laboratory, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Prakash Vishnu
- Division of Hematology, CHI Franciscan Medical Group, Seattle, United States
| | - Lukas Graf
- Cantonal Hospital of St Gallen, Switzerland
| | | | - Raphael Sznitman
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Tamam Bakchoul
- Centre for Clinical Transfusion Medicine, University Hospital of Tübingen, Tübingen, Germany
| | - Michael Nagler
- Department of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Corresponding author. Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland.
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Genome-wide association study of platelet factor 4/heparin antibodies in heparin-induced thrombocytopenia. Blood Adv 2022; 6:4137-4146. [PMID: 35533259 PMCID: PMC9327558 DOI: 10.1182/bloodadvances.2022007673] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/02/2022] [Indexed: 11/20/2022] Open
Abstract
Heparin, a widely used anticoagulant, carries the risk of an antibody mediated adverse drug reaction, heparin-induced thrombocytopenia (HIT). A subset of heparin-treated patients produces detectable levels of antibodies against complexes of heparin bound to circulating platelet factor 4 (PF4). Using a genome-wide association study (GWAS) approach, we aimed to identify genetic variants associated with anti-PF4/heparin antibodies that account for the variable antibody response seen in HIT. We performed a GWAS on anti-PF4/heparin antibody levels determined via polyclonal enzyme-linked immunosorbent assays (ELISA). Our discovery cohort (n=4237) and replication cohort (n=807) constituted patients with European ancestry and clinical suspicion of HIT with cases confirmed via functional assay. Genome-wide significance was considered at α=5x10-8. No variants were significantly associated with anti-PF4/heparin antibody levels in the discovery cohort at a genome-wide significant level. Secondary GWAS analyses included identification of variants with suggestive associations in the discovery cohort (α=1x10-4). The top variant in both cohorts was rs1555175145 (discovery β=-0.112[0.018], p=2.50x10-5; replication β=-0.104[0.051], p=0.041). In gene set enrichment analysis (GSEA), three gene sets reached false discovery rate-adjusted significance (q<0.05) in both discovery and replication cohorts: "Leukocyte Transendothelial Migration," "Innate Immune Response," and "Lyase Activity." Our results indicate that genomic variation is not significantly associated with anti-PF4/heparin antibody levels. Given our power to identify variants with moderate frequencies and effect sizes, this evidence suggests genetic variation is not a primary driver of variable antibody response in heparin-treated patients with European ancestry.
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Gonthier MC, Gendron N, Eloy P, Bourrienne MC, Alhenc-Gelas M, Pouplard C, Tardy B, Szymezak J, Burdet C, Gkalea V, Faille D, Ajzenberg N. Heparin-induced Thrombocytopenia Diagnosis: A Retrospective Study Comparing Heparin-induced Platelet Activation Test to 14 C-serotonin Release Assay. TH OPEN 2021; 5:e507-e512. [PMID: 34778697 PMCID: PMC8577886 DOI: 10.1055/a-1653-5065] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/08/2021] [Indexed: 11/23/2022] Open
Abstract
Laboratory confirmation of heparin-induced thrombocytopenia (HIT) is of crucial importance and remains challenging and relies on platelet functional assays highlighting the presence of heparin-dependent platelet-activating antibodies in patient serum or plasma. Platelet functional assays using washed platelets include the
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C-serotonin release assay (SRA), usually described as the gold standard, and the heparin-induced platelet activation assay (HIPA). Since its first comparison with SRA there has been no additional published study regarding HIPA diagnostic performances compared with SRA. Aim of our retrospective study was to compare the concordance between HIPA and SRA in HIT suspected-patients with positive anti-PF4/heparin antibodies between October 2010 and October 2015. Fifty-five HIT-suspected patients who beneficiated from both HIPA and SRA were included. Positive and negative percent agreements were 83.8% (95% CI 68.0–93.8%) and 66.7% (95% CI 41.0–86.7%), respectively. Overall percent agreement was 78.2% (95% CI 65.0–92.2%). Agreement was higher in patients who underwent cardiopulmonary bypass with extracorporeal circulation circuit for cardiac surgery. We also confirm that the use of a minimum of 2 platelet donors to establish positive HIT diagnosis and 4 platelet donors to exclude HIT diagnosis allows obtaining a good agreement with SRA. Although HIPA and SRA were performed with different platelet donors and in different laboratories, HIPA had a good positive agreement with SRA for HIT diagnosis, showing that HIPA is a useful functional assay that does not require radioactivity and could be developed worldwide to improve HIT diagnosis.
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Affiliation(s)
- Marie-Caroline Gonthier
- Laboratory of Vascular Translational Science, Université de Paris, INSERM, et Laboratoire d'Hématologie, AH-HP, Bichat-Claude Bernard Hospital, Paris, France
| | - Nicolas Gendron
- Laboratory of Vascular Translational Science, Université de Paris, INSERM, et Laboratoire d'Hématologie, AH-HP, Bichat-Claude Bernard Hospital, Paris, France.,Hematology Department and Biosurgical Research Lab (Carpentier Foundation), Assistance Publique Hôpitaux de Paris.Centre-Université de Paris (APHP-CUP), Paris, France
| | - Philippine Eloy
- Département d'Epidémiologie, Biostatistique et Recherche Clinique, AH-HP, Bichat-Claude Bernard Hospital, Paris, France
| | - Marie-Charlotte Bourrienne
- Laboratory of Vascular Translational Science, Université de Paris, INSERM, et Laboratoire d'Hématologie, AH-HP, Bichat-Claude Bernard Hospital, Paris, France
| | - Martine Alhenc-Gelas
- Hematology Department and Biosurgical Research Lab (Carpentier Foundation), Assistance Publique Hôpitaux de Paris.Centre-Université de Paris (APHP-CUP), Paris, France
| | - Claire Pouplard
- CHRU Tours, Service d'hématologie-hémostase, Université de Tours, Tours, France
| | - Bernard Tardy
- Inserm CIC 1408 CHU Saint Etienne, Saint-Etienne, France
| | - Jean Szymezak
- Laboratoire d'hématologie, CHU Robert Debré, Reims, France
| | - Charles Burdet
- Département d'Epidémiologie, Biostatistique et Recherche Clinique, AH-HP, Bichat-Claude Bernard Hospital, Paris, France.,Université de Paris, IAME, INSERM, Paris, France
| | - Vasiliki Gkalea
- Laboratory of Vascular Translational Science, Université de Paris, INSERM, et Laboratoire d'Hématologie, AH-HP, Bichat-Claude Bernard Hospital, Paris, France
| | - Dorothée Faille
- Laboratory of Vascular Translational Science, Université de Paris, INSERM, et Laboratoire d'Hématologie, AH-HP, Bichat-Claude Bernard Hospital, Paris, France
| | - Nadine Ajzenberg
- Laboratory of Vascular Translational Science, Université de Paris, INSERM, et Laboratoire d'Hématologie, AH-HP, Bichat-Claude Bernard Hospital, Paris, France
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6
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Tardy-Poncet B, de Maistre E, Pouplard C, Presles E, Alhenc-Gelas M, Lasne D, Horellou MH, Mouton C, Serre-Sapin A, Bauters A, Nguyen P, Mullier F, Perrin J, Le Gal G, Morange PE, Grunebaum L, Lillo-Le Louet A, Elalamy I, Gruel Y, Greinacher A, Lecompte T, Tardy B. Heparin-induced thrombocytopenia: Construction of a pretest diagnostic score derived from the analysis of a prospective multinational database, with internal validation. J Thromb Haemost 2021; 19:1959-1972. [PMID: 33872452 DOI: 10.1111/jth.15344] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 04/09/2021] [Accepted: 04/09/2021] [Indexed: 12/18/2022]
Abstract
BACKGROUND Diagnosis of heparin-induced thrombocytopenia (HIT) requires pretest probability assessment and dedicated laboratory assays. OBJECTIVE To develop a pretest score for HIT. DESIGN Observational; analysis of prospectively collected data of hospitalized patients suspected with HIT (ClinicalTrials.gov NCT00748839). SETTING Thirty-one tertiary hospitals in France, Switzerland, and Belgium. PATIENTS Patients tested for HIT antibodies (2280 evaluable), randomly allocated to derivation and validation cohorts. MEASUREMENTS Independent adjudicators diagnosed HIT based on the prospectively collected data and serotonin release assay results. RESULTS Heparin-induced thrombocytopenia was diagnosed in 234 (14.7%) and 99 (14.5%) patients in the two cohorts. Eight features were associated with HIT (in brackets, points assigned for score calculation of the score): unfractionated heparin (1); therapeutic-dose heparin (1); cardiopulmonary bypass (cardiac surgery) (2); major trauma (3); 5- to 21-day interval from anticoagulation initiation to suspicion of HIT (4); ≥40% decrease in platelet count over ≤6 days (3); thrombotic event, arterial (3) or venous (3). The C-statistic was 0.79 (95% CI, 0.76-0.82). In the validation cohort, the area under the receiver operating characteristic curve was 0.77 (95% CI, 0.74-0.80). Three groups of scores were defined; HIT prevalence reached almost 30% in the high-probability group. LIMITATION The performance of the score may depend on settings and practices. CONCLUSION The objective, easy-to-collect, clinical features of HIT we evidenced were incorporated into a pretest score, which may guide clinical decisions regarding diagnostic testing and anticoagulation.
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Affiliation(s)
- Brigitte Tardy-Poncet
- CIC 1408, Inserm U1059 SAINBIOSE, F-Crin INNOVTE, Université de Lyon, Saint-Etienne, France
| | | | - Claire Pouplard
- Division of Hematology - Hemostasis, University Hospital of Tours, Tours, France
| | - Emilie Presles
- CIC 1408, Inserm U1059 SAINBIOSE, F-Crin INNOVTE, Université de Lyon, Saint-Etienne, France
| | | | - Dominique Lasne
- Hemostasis Unit, Hôpital Necker, AP-HP, Paris, France
- Université Paris Sud Paris Saclay, Inserm U1176, Le Kremlin-Bicêtre, France
| | | | | | | | | | | | - François Mullier
- Namur Thrombosis and Hemostasis Center, Hematology Laboratory, Université catholique de Louvain, CHU UCL Namur, Yvoir, Belgium
| | | | - Grégoire Le Gal
- Department of Medicine, University of Ottawa, Ottawa Hospital Research Institute, Thrombosis Research Group, Ottawa, ON, Canada
| | - Pierre-Emmanuel Morange
- C2VN, Aix Marseille University, INSERM, INRA; Laboratory of Hematology, La Timone Hospital, Assistance Publique des Hôpitaux de Marseille, Marseille, France
| | - Lélia Grunebaum
- Laboratory of Hematology, CHU Strasbourg, Strasbourg, France
| | - Agnès Lillo-Le Louet
- Pharmacovigilance Center, Georges Pompidou European Hospital, AP-HP, Paris, France
| | - Ismail Elalamy
- Hematology and Thrombosis Center, Tenon University Hospital, INSERM UMRS 938, Sorbonne University, Paris, France
| | - Yves Gruel
- Division of Hematology - Hemostasis, University Hospital of Tours, Tours, France
| | - Andreas Greinacher
- Institut fuer Immunologie und Transfusionsmedizin, Universitaetsmedizin Greifswald, Greifswald, Germany
| | - Thomas Lecompte
- Department of Medicine, Geneva University Hospitals, and Geneva Platelet Group (GpG), Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Bernard Tardy
- CIC 1408, Inserm U1059 SAINBIOSE, F-Crin INNOVTE, Université de Lyon, Saint-Etienne, France
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7
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Warkentin TE, Smythe MA, Ali MA, Aslam N, Sheppard JI, Smith JW, Moore JC, Arnold DM, Nazy I. Serotonin-release assay-positive but platelet factor 4-dependent enzyme-immunoassay negative: HIT or not HIT? Am J Hematol 2021; 96:320-329. [PMID: 33326124 DOI: 10.1002/ajh.26075] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/07/2020] [Accepted: 12/14/2020] [Indexed: 12/28/2022]
Abstract
IgG-specific and polyspecific PF4-dependent enzyme-immunoassays (EIAs) have exceptionally high sensitivity (≥99%) for diagnosis of heparin-induced thrombocytopenia (HIT), a drug reaction caused by platelet-activating antibodies detectable by serotonin-release assay (SRA). The IgG-specific EIAs are recommended for screening, as their high sensitivity is accompanied by relatively high specificity vis-à-vis polyspecific EIAs. We investigated the frequency of SRA-positive/EIA-negative (SRA+/EIA-) HIT, prompted by referral to our reference HIT laboratory of serial blood samples from a patient ("index case") with false-negative IgG-specific EIAs. Despite initial clinical suspicion for HIT, repeat negative IgG-specific EIAs prompted heparin resumption, which triggered recurrent thrombocytopenia and near-fatal cardiac arrest, indicating likely post-heparin HIT-associated anaphylactoid reaction. Further investigations revealed a strong-positive SRA, whether performed with heparin alone, PF4 alone, or PF4/heparin, with inhibition by Fc receptor-blocking monoclonal antibody (indicating IgG-mediated platelet activation); however, five different IgG-specific immunoassays yielded primarily negative (or weak-positive) results. To investigate the frequency of SRA+/EIA- HIT, we reviewed the laboratory and clinical features of patients with this serological profile during a 6-year period in which our reference laboratory investigated for HIT using both SRA and IgG-specific EIA. Although ~0.2% of 8546 patients had an SRA+/EIA- profile, further review of 15 such cases indicated clerical/laboratory misclassification or false-positive SRA in all, with no SRA+/EIA- HIT case identified. We conclude that while SRA+/EIA- HIT is possible-as shown by our index case-this clinical picture is exceptionally uncommon. Moreover, the requirement for a positive EIA is a useful quality control maneuver that reduces risk of reporting a false-positive SRA result.
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Affiliation(s)
- Theodore E. Warkentin
- Department of Pathology and Molecular Medicine Michael G. DeGroote School of Medicine Hamilton Ontario Canada
- Department of Medicine Michael G. DeGroote School of Medicine Hamilton Ontario Canada
- McMaster Centre for Transfusion Research Hamilton Ontario Canada
| | - Maureen A. Smythe
- Department of Pharmaceutical Services Beaumont Hospital Royal Oak Michigan USA
- Department of Pharmacy Practice Wayne State University Detroit Michigan USA
- Oakland University William Beaumont School of Medicine Rochester Michigan USA
| | - Mona A. Ali
- Department of Pharmaceutical Services Beaumont Hospital Royal Oak Michigan USA
| | - Naveed Aslam
- Oakland University William Beaumont School of Medicine Rochester Michigan USA
| | - Jo‐Ann I. Sheppard
- Department of Pathology and Molecular Medicine Michael G. DeGroote School of Medicine Hamilton Ontario Canada
| | - James W. Smith
- Department of Medicine Michael G. DeGroote School of Medicine Hamilton Ontario Canada
| | - Jane C. Moore
- Department of Medicine Michael G. DeGroote School of Medicine Hamilton Ontario Canada
| | - Donald M. Arnold
- Department of Medicine Michael G. DeGroote School of Medicine Hamilton Ontario Canada
- McMaster Centre for Transfusion Research Hamilton Ontario Canada
| | - Ishac Nazy
- Department of Medicine Michael G. DeGroote School of Medicine Hamilton Ontario Canada
- McMaster Centre for Transfusion Research Hamilton Ontario Canada
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8
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Marashi-Sabouni Z, Vayne C, Ibrahim-Kosta M, Guidon C, Loundou A, Guery EA, Morange PE, Camoin-Jau L. Clinical validation of immunoassay HemosIL® AcuStar HIT-IgG (PF4-H) in the diagnosis of Heparin-induced thrombocytopenia. J Thromb Thrombolysis 2021; 52:601-609. [PMID: 33386560 DOI: 10.1007/s11239-020-02349-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/17/2020] [Indexed: 11/25/2022]
Abstract
Heparin induced thrombocytopenia (HIT) is a life and limb-threatening complication of heparin exposure. The misdiagnosis of this disease can have major consequences on the patients. The objective of this study was to evaluate a diagnostic strategy that combines the 4Ts score with the result of HemosIL® AcuStar HIT-IgG (PF4-H) to confirm the diagnosis of HIT. Citrated plasmas from 1300 patients with suspicion of HIT were analyzed with a fully automated quantitative chemiluminescent immunoassay (HemosIL® AcuStar HIT-IgG (PF4/H)). If the IgG anti-PF4/H antibodies were positive (cut-off, 1 U/mL), HIT diagnosis was confirmed using functional tests. In total, 1300 samples of consecutive patients were enrolled, 94 (7.2%) of which gave positive results in HemosIL® AcuStar-IgG. HIT was diagnosed in 65 out of these patients, corresponding to a prevalence of 5%. Using ROC curve analysis, patients were divided into three groups according to their titer of antibodies. Higher values of the IgG (PF4-H) were associated with increased probability of HIT, and the diagnostic specificity was greatly increased using the combination of a 4Ts score > 3 and a positive titer ≥ 3.25 U/mL. Importantly, the diagnostic specificity is 100% when the titer is > 12.40 U/mL. We demonstrated that higher values of Anti PF4/H Antibodies were associated with a high probability of having HIT. A titer of HemosIL® IgG (PF4-H) > 12.40 U/mL has a specificity of 100% which should no require a functional test to confirm the diagnosis of HIT.
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Affiliation(s)
- Zeina Marashi-Sabouni
- Laboratoire d'Hématologie, La Timone Hospital, APHM, Boulevard Jean- Moulin, 13005, Marseille, France
| | - Caroline Vayne
- Service d'Hématologie Hémostase, Hôpital Trousseau, CHU de Tours, 37044, Tours, France
- EA7501 GICC, Université de Tours, Tours, France
| | - Manal Ibrahim-Kosta
- Laboratoire d'Hématologie, La Timone Hospital, APHM, Boulevard Jean- Moulin, 13005, Marseille, France
- Aix Marseille Univ, INSERM, INRAE, C2VN, Marseille, France
| | - Catherine Guidon
- Department of Anaesthesiology and Critical Care Medicine, University Hospital Timone, Marseille, France
| | - Anderson Loundou
- Biostatistic and Public Health Department, La Timone Hospital, Marseille, France
| | - Eve Anne Guery
- Service d'Hématologie Hémostase, Hôpital Trousseau, CHU de Tours, 37044, Tours, France
| | - Pierre-Emmanuel Morange
- Laboratoire d'Hématologie, La Timone Hospital, APHM, Boulevard Jean- Moulin, 13005, Marseille, France
- Aix Marseille Univ, INSERM, INRAE, C2VN, Marseille, France
| | - Laurence Camoin-Jau
- Laboratoire d'Hématologie, La Timone Hospital, APHM, Boulevard Jean- Moulin, 13005, Marseille, France.
- Aix Marseille Univ, IRD, APHM, MEPHI, IHU Méditerranée Infection, Marseille, France.
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Warkentin TE, Sheppard JI, Smith JW, Li N, Moore JC, Arnold DM, Nazy I. Combination of two complementary automated rapid assays for diagnosis of heparin-induced thrombocytopenia (HIT). J Thromb Haemost 2020; 18:1435-1446. [PMID: 32167669 PMCID: PMC7317897 DOI: 10.1111/jth.14794] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 03/10/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND HIT diagnosis typically uses complementary diagnostic assays (eg, a PF4-dependent enzyme-immunoassay [EIA] and a platelet activation assay such as the serotonin-release assay [SRA]). OBJECTIVES To determine whether the combination of two automated assays-a latex immunoturbidimetric assay (LIA) that evaluates competitive inhibition of a HIT-like monoclonal antibody and a chemiluminescence immunoassay (CLIA) for detecting anti-PF4/heparin IgG-optimizes diagnostic sensitivity while also yielding good specificity, particularly at high assay reactivities. PATIENTS/METHODS We determined operating characteristics using combined LIA/CLIA results from a HIT observational trial (n = 430; derivation cohort) and 147 consecutive patients with HIT (n = 147; supplementary derivation cohort). We also evaluated 678 consecutive samples referred for HIT testing (replication cohort). LIA/CLIA reactivities were scored individually as "negative" (<1.00 U/mL, 0 points), "weak" (1.00-4.99 U/mL, 1 point), "moderate" (5.00-15.99 U/mL, 2 points) and "strong" (≥16.00 U/mL, 3 points), thus contributing up to 6 points (maximum) when LIA/CLIA results were combined. We also examined whether higher LIA/CLIA scores predicted presence of platelet-activating antibodies by conventional and modified (PF4- or PF4/heparin-enhanced) SRA. RESULTS Combined LIA/CLIA testing yielded high diagnostic sensitivity (~99%) similar to EIA. Interpretation of LIA/CLIA results using the 6-point scale indicated progressively greater likelihood for the presence of platelet-activating antibodies with increasing scores (semi-quantitative reactivity). A LIA/CLIA score ≥ 4 points predicted the presence of platelet-activating antibodies by SRA or PF4-enhanced SRA with high probability (~98%). CONCLUSION Combined LIA/CLIA testing optimizes diagnostic sensitivity, with progressively greater probability of detecting platelet-activating antibodies with higher assay reactivity that reaches 98% when both automated assays yield moderate or strong results.
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Affiliation(s)
- Theodore E. Warkentin
- Department of Pathology and Molecular MedicineMichael G. DeGroote School of MedicineMcMaster UniversityHamiltonONCanada
- Department of MedicineMichael G. DeGroote School of MedicineMcMaster UniversityHamiltonONCanada
- Hamilton Regional Laboratory Medicine ProgramHamilton Health SciencesHamiltonONCanada
- McMaster Centre for Transfusion ResearchHamiltonONCanada
| | - Jo‐Ann I. Sheppard
- Department of Pathology and Molecular MedicineMichael G. DeGroote School of MedicineMcMaster UniversityHamiltonONCanada
| | - James W. Smith
- Department of MedicineMichael G. DeGroote School of MedicineMcMaster UniversityHamiltonONCanada
| | - Na Li
- McMaster Centre for Transfusion ResearchHamiltonONCanada
- Department of Computing and SoftwareMcMaster UniversityHamiltonONCanada
| | - Jane C. Moore
- Department of MedicineMichael G. DeGroote School of MedicineMcMaster UniversityHamiltonONCanada
| | - Donald M. Arnold
- Department of MedicineMichael G. DeGroote School of MedicineMcMaster UniversityHamiltonONCanada
- McMaster Centre for Transfusion ResearchHamiltonONCanada
| | - Ishac Nazy
- Department of MedicineMichael G. DeGroote School of MedicineMcMaster UniversityHamiltonONCanada
- McMaster Centre for Transfusion ResearchHamiltonONCanada
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10
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Althaus K, Straub A, Häberle H, Rosenberger P, Hidiatov O, Hammer S, Nowak-Harnau S, Enkel S, Riessen R, Bakchoul T. Heparin-induced thrombocytopenia: Diagnostic challenges in intensive care patients especially with extracorporeal circulation. Thromb Res 2020; 188:52-60. [PMID: 32059134 DOI: 10.1016/j.thromres.2020.01.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 01/09/2020] [Accepted: 01/27/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Heparin-induced thrombocytopenia (HIT) is a serious drug induced reaction that may be associated with life threatening complications. Platelet-activating antibodies directed against platelet factor 4 (PF4)/heparin complexes cause the disease. The diagnosis of HIT is challenging, as thrombocytopenia is a frequent finding in intensive care (ICU) patient population, especially during extracorporeal membrane oxygenation. OBJECTIVE To investigate the performance of a diagnostic algorithm for HIT in ICU patients. METHODS ICU patients who developed thrombocytopenia or thrombosis under heparin treatment were included in this study. The pretest probability for HIT was estimated using the 4Ts-score and patient's sera were tested using two rapid immunoassays (RA) LFI-HIT and PaGIA (from Milenia Biotec and DiaMed), and within 72 h using the IgG enzyme immunoassay (EIA) from Hyphen and the heparin induced platelet activation assay (HIPA). RESULTS 392 consecutive ICU patients with suspected HIT were enrolled in this study, of whom 83/392 (21.2%) patients had extracorporeal circulation. Sera from 120/392 (30.6%) and 98/392 (25.0%) patients revealed positive results in RA and IgG EIA, respectively. The HIPA test revealed heparin-dependent platelet activation in a total of 15/392 (3.8%) ICU patients (3 medical and 12 surgical patients). In addition, sera from 7 patients revealed indeterminate HIPA results, of whom 2 patients had a clinical course compatible with HIT. CONCLUSIONS Data from our study confirm the high frequency of IgG PF4/heparin antibodies in ICU patients under unfractionated heparin and shows that the combination of 4Ts-score and RA does not reduce the laboratory overinvestigation for HIT in these patients.
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Affiliation(s)
- Karina Althaus
- Center for Clinical Transfusion Medicine, University of Tübingen, Tübingen, Germany; Transfusion Medicine, Medical Faculty of Tübingen, Tübingen, Germany
| | - Andreas Straub
- Department of Anesthesiology and Intensive Care Medicine, University of Tübingen, Tübingen, Germany
| | - Helene Häberle
- Department of Anesthesiology and Intensive Care Medicine, University of Tübingen, Tübingen, Germany
| | - Peter Rosenberger
- Department of Anesthesiology and Intensive Care Medicine, University of Tübingen, Tübingen, Germany
| | - Oleg Hidiatov
- Transfusion Medicine, Medical Faculty of Tübingen, Tübingen, Germany
| | - Stefanie Hammer
- Center for Clinical Transfusion Medicine, University of Tübingen, Tübingen, Germany
| | | | - Sigrid Enkel
- Center for Clinical Transfusion Medicine, University of Tübingen, Tübingen, Germany
| | - Reimer Riessen
- Medical Intensive Care Unit, Department of Medicine, University of Tübingen, Tübingen, Germany
| | - Tamam Bakchoul
- Center for Clinical Transfusion Medicine, University of Tübingen, Tübingen, Germany; Transfusion Medicine, Medical Faculty of Tübingen, Tübingen, Germany.
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11
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Warkentin TE, Nazy I, Sheppard JI, Smith JW, Kelton JG, Arnold DM. Serotonin-release assay-negative heparin-induced thrombocytopenia. Am J Hematol 2020; 95:38-47. [PMID: 31621093 DOI: 10.1002/ajh.25660] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/09/2019] [Accepted: 10/13/2019] [Indexed: 12/22/2022]
Abstract
Heparin-induced thrombocytopenia (HIT) is a prothrombotic drug reaction caused by platelet-activating anti-platelet factor 4 (PF4)/heparin antibodies. Pathogenic HIT antibodies can be detected by the serotonin-release assay (SRA), a platelet activation test. We have regarded the SRA performed in our medical community ("McMaster" SRA) as having high sensitivity and specificity. Recently, the concept of "SRA-negative HIT" has been proposed for enzyme-immunoassay (EIA)-positive/SRA-negative patients with a HIT-compatible clinical picture, who test positive in a PF4-enhanced platelet activation assay. After identifying an index case of SRA-negative HIT, we estimated the frequency of this condition by performing the "PF4-SRA" (modified SRA using high concentrations of added PF4 rather than heparin) in EIA-positive patients from a cohort study evaluating clinical and laboratory diagnosis of HIT. We defined SRA-negative HIT as patients meeting three criteria: clinical picture compatible with HIT (4Ts ≥ 4 points); EIA-positive (≥1.00 units); and PF4-SRA-positive. Among 430 patients, 35 were EIA-positive/SRA-positive and 27 were EIA-positive/SRA-negative. Among these 27 SRA-negative patients, three were found to have subthreshold levels of platelet-activating antibodies by PF4-SRA, of whom one met clinical criteria for SRA-negative HIT. Thus, based on identifying one patient with SRA-negative HIT within a cohort study that found 35 SRA-positive HIT patients, we estimate the sensitivity of the McMaster SRA for diagnosis of HIT to be 35/36 (97.2%; 95% CI, 85.8-99.9%). Although the McMaster SRA is highly sensitive for HIT, occasional SRA-negative but EIA-positive patients strongly suspected of having HIT can have this diagnosis supported by a PF4-enhanced activation assay such as the PF4-SRA.
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Affiliation(s)
- Theodore E. Warkentin
- Department of Pathology and Molecular MedicineMichael G. DeGroote School of Medicine Hamilton Ontario Canada
- Department of MedicineMichael G. DeGroote School of Medicine Hamilton Ontario Canada
- McMaster Centre for Transfusion Research Hamilton Ontario Canada
| | - Ishac Nazy
- Department of MedicineMichael G. DeGroote School of Medicine Hamilton Ontario Canada
- McMaster Centre for Transfusion Research Hamilton Ontario Canada
| | - Jo‐Ann I. Sheppard
- Department of Pathology and Molecular MedicineMichael G. DeGroote School of Medicine Hamilton Ontario Canada
| | - James W. Smith
- Department of MedicineMichael G. DeGroote School of Medicine Hamilton Ontario Canada
| | - John G. Kelton
- Department of MedicineMichael G. DeGroote School of Medicine Hamilton Ontario Canada
- McMaster Centre for Transfusion Research Hamilton Ontario Canada
| | - Donald M. Arnold
- Department of MedicineMichael G. DeGroote School of Medicine Hamilton Ontario Canada
- McMaster Centre for Transfusion Research Hamilton Ontario Canada
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12
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Joseph J, Rabbolini D, Enjeti AK, Favaloro E, Kopp M, McRae S, Pasalic L, Tan CW, Ward CM, Chong BH. Diagnosis and management of heparin‐induced thrombocytopenia: a consensus statement from the Thrombosis and Haemostasis Society of Australia and New ZealandHITWriting Group. Med J Aust 2019; 210:509-516. [DOI: 10.5694/mja2.50213] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Joanne Joseph
- St Vincent's Hospital Sydney NSW
- St Vincent's Clinical SchoolUniversity of New South Wales Sydney NSW
| | - David Rabbolini
- Royal North Shore Hospital Sydney NSW
- Northern Blood Research CentreKolling Institute of Medical Research Sydney NSW
| | | | - Emmanuel Favaloro
- Institute of Clinical Pathology and Medical Research Sydney NSW
- Westmead Hospital Sydney NSW
| | | | | | - Leonardo Pasalic
- Institute of Clinical Pathology and Medical Research Sydney NSW
- Westmead Hospital Sydney NSW
| | | | - Christopher M Ward
- Royal North Shore Hospital Sydney NSW
- Northern Blood Research CentreKolling Institute of Medical Research Sydney NSW
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13
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Eekels JJM, Althaus K, Bakchoul T, Kroll H, Kiefel V, Nazy I, Lee LS, Sachs U, Warkentin TE, Greinacher A. An international external quality assessment for laboratory diagnosis of heparin-induced thrombocytopenia. J Thromb Haemost 2019; 17:525-531. [PMID: 30640980 DOI: 10.1111/jth.14383] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Indexed: 01/13/2023]
Abstract
Essentials A pilot study for External Quality Assessment for testing of HIT is described. The qualitative accordance for the PF4/heparin IgG test was 97.6%. The qualitative accordance for functional HIT tests was considerably lower. External Quality Assessment for functional HIT tests is required. SUMMARY: Objective Heparin-induced thrombocytopenia (HIT) is a potentially life-threatening complication of heparin exposure. Diagnosis is most reliable using a combination of an enzyme immunoassay (EIA) that detects antibodies against platelet factor 4 (PF4)/heparin complexes ("antigen" assay) and a "functional" assay that detects platelet-activating properties of the pathogenic HIT antibodies. No External Quality Assessment (EQA) is available for a combination of the tests. Here we report on the results of the first international EQA. Methods The pilot EQA was organized by the Department of Transfusion Medicine, Universitätsmedizin Greifswald, Germany. Six serum samples of patients, which were referred to Greifswald for HIT diagnosis, and one negative control sample were distributed to seven participants in Germany, Canada, and Singapore. Participants were asked to report the optical density (OD) values of their local EIA test for IgG-specific antibodies against the PF4/heparin complexes and the results for a functional assay (HIPA or SRA). Consensus was defined as a minimum 70% agreement, i.e., agreement among at least five of the seven participating laboratories. Results and conclusion Six out of seven participants reported results for EIA, with a high quantitative accordance (97.6%). For the functional assay, consensus was reached for all samples except the negative control, for which some participants reported nonspecific reactivity. All HIT-negative samples were correctly diagnosed by all participants; for HIT-positive samples, consensus of 70% was reached. Although the limited availability of sample material is an obstacle to overcome, an EQA combining both EIA and functional testing is feasible.
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Affiliation(s)
- Julia J M Eekels
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Karina Althaus
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
- Transfusion Medicine, Medical Faculty of Tübingen, Tübingen, Germany
| | - Tamam Bakchoul
- Transfusion Medicine, Medical Faculty of Tübingen, Tübingen, Germany
| | - Hartmut Kroll
- Institute for Transfusion Medicine Dessau, Red Cross Blood Transfusion Service NSTOB, Dessau, Germany
| | - Volker Kiefel
- Institut für Transfusionsmedizin, Universitätsmedizin Rostock, Rostock, Germany
| | - Ishac Nazy
- Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON, Canada
| | - Lau Soon Lee
- Department of Laboratory Medicine, Tan Tock Seng Hospital, Singapore, Singapore
| | - Ulrich Sachs
- Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany
| | - Theodore E Warkentin
- Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Andreas Greinacher
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
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14
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Heparin-Induced Thrombocytopenia. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00041-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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15
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Gameiro J, Jorge S, Lopes JA. Haemodialysis-related-heparin-induced thrombocytopenia: Case series and literature review. Nefrologia 2018; 38:551-557. [PMID: 29871769 DOI: 10.1016/j.nefro.2018.02.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 02/12/2018] [Accepted: 02/27/2018] [Indexed: 01/18/2023] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is a serious and life-threatening complication that occurs in five per cent of patients exposed to heparin. It should be considered in patients with a platelet count <100×109cells/l or a >50% decrease from baseline count in association with heparin therapy. Thromboembolic complications develop in 50% of patients. Bleeding is rare as the platelet count nadir typically does not drop below 20×109cells/l. Up to 12% of dialysis patients develop HIT, named haemodialysis-related-heparin-induced thrombocytopenia (HD-HIT), as they are a risk group with continuous exposure to heparin. The definition of HD-HIT is less strict, in the range of a platelet count decrease of 30% and below 150×109cells/l due to the intermittent use of heparin. Heparin cessation and alternative anticoagulation are the key interventions in patients with HIT. In dialysis patients, citrate anticoagulation, heparin-free dialysis or peritoneal dialysis are options that must be considered. The authors describe the presentation, diagnosis, treatment and outcomes of five cases of HD-HIT, and emphasize the importance of an accurate diagnosis and early intervention in order to reduce the mortality risk, which can be as high as 20 per cent.
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Affiliation(s)
- Joana Gameiro
- Division of Nephrology and Renal Transplantation, Department of Medicine, Centro Hospitalar Lisboa Norte, EPE, Av. Prof. Egas Moniz, 1649-035 Lisboa, Portugal.
| | - Sofia Jorge
- Division of Nephrology and Renal Transplantation, Department of Medicine, Centro Hospitalar Lisboa Norte, EPE, Av. Prof. Egas Moniz, 1649-035 Lisboa, Portugal
| | - José António Lopes
- Division of Nephrology and Renal Transplantation, Department of Medicine, Centro Hospitalar Lisboa Norte, EPE, Av. Prof. Egas Moniz, 1649-035 Lisboa, Portugal
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16
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Nagler M, Bakchoul T. Clinical and laboratory tests for the diagnosis of heparin-induced thrombocytopenia. Thromb Haemost 2017; 116:823-834. [DOI: 10.1160/th16-03-0240] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 08/16/2016] [Indexed: 12/27/2022]
Abstract
SummaryA rapid diagnostic work-up is required in patients with suspected heparin-induced thrombocytopenia (HIT). However, diagnosis of HIT is challenging due to a number of practical issues and methodological limitations. Many laboratory tests and a few clinical scoring systems are available but the individual characteristics and the diagnostic accuracy of these are hard to appraise. The 4Ts score is a well evaluated clinical assessment tool with the potential to rule out HIT in many patients. Still, it requires experience and is subject to a relevant inter-observer variability. Immunoassays such as enzyme-linked immunosorbent assays or recently developed rapid assays are able to exclude HIT in a number of patients. But, accuracy of immunoassays differs depending on type of assay, threshold, antibody specificity and even manufacturer. Due to a comparatively low positive predictive value, HIT cannot be confirmed by immunoassays alone. In addition, only some of them are immediately accessible, particularly in small laboratories. While functional assays such as the serotonin release assay (SRA) and the heparin-induced platelet activation assay (HIPA) are considered as gold standard for diagnosis of HIT, they require a highly specialised laboratory. In addition, some of them are not adequately evaluated. In clinical practice, we recommend an integrated diagnostic approach combining not only clinical assessment (the 4Ts score) but immunoassays and functional assays as well. We propose a clear diagnostic algorithm supporting clinical decision-making. Furthermore, we provide an overview of all current laboratory techniques for HIT and discuss diagnostic pathways and strategies to reduce diagnostic errors, and future perspectives.
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17
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Hesberg J, Santoso S, Bein G, Bakchoul T, Sachs U. Evaluation of a new nanoparticle-based lateral-flow immunoassay for the exclusion of heparin-induced thrombocytopenia (HIT). Thromb Haemost 2017. [DOI: 10.1160/th11-06-0390] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
SummaryHeparin-induced thrombocytopenia (HIT) is an adverse complication of heparin caused by HIT antibodies (abs) that recognise platelet factor 4-heparin (PF4/hep) complexes. Several laboratory tests are available for the confirmation and/or refutation of HIT. A reliable and rapid singlesample test is still pending. It was the objective of this study to evaluate a new lateral-flow immunoassay based on nanoparticle technology. A cohort of 452 surgical and medical patients suspected of having HIT was evaluated. All samples were tested in two IgG-specific ELISAs, in a particle gel immunoassay (PaGIA) and in a newly developed lateral-flow immunoassay (LFI-HIT) as well as in a functional test (HIPA). Clinical pre-test probability was determined using 4T's score. Platelet-activating antibodies were present in 34/452 patients, all of whom had intermediate to high clinical probability. PF4/hep abs were detected in 79, 87, 86, and 63 sera using the four different immunoassays. The negative predictive values (NPV) were 100% for both ELISA tests and LFI-HIT but only 99.2% for PaGIA. There were less false positives (n=29) in the LFI-HIT compared to any other test. Additionally, significantly less time was required to perform LFI-HIT than to perform the other immunoassays. In conclusion, a newly developed lateral-flow assay, LFI-HIT, was capable of identifying all HIT patients in a cohort in a short period of time. Beside an NPV of 100%, the rate of false-positive signals is significantly lower with LFI-HIT than with other immunoassay(s). These performance characteristics suggest a high potency in reducing the risk and costs in patients suspected of having HIT.
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18
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Maličev E, Maček Kvanka M, Klemenc P, Rožman P. The level of heparin-induced antibodies in correlation with the result of the flow cytometric functional assay in the patients with suspected HIT. J Clin Pathol 2017; 70:1084-1087. [DOI: 10.1136/jclinpath-2017-204498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Indexed: 02/03/2023]
Abstract
Heparin can induce the formation of antibodies against a heparin complex with a platelet factor 4 (PF4), leading to platelet activation and the development of heparin-induced thrombocytopaenia (HIT). Because screening ELISA does not discriminate between platelet activating and non-activating anti-heparin/PF4 antibodies, each positive result is confirmed by an additional functional assay. We analysed 1004 sera of patients with suspected HIT. Optical density (OD) values of ELISA-positive results were correlated with the risk for a positive result with our functional flow cytometric assay. Only 10.7% were ELISA positive and 59.8% of those were positive with the functional assay. The positive functional assay was found in 23.4% of patients with OD<1.0, in 57.7% with 1.0<OD<2.0 and in 94.1% with OD>2.0. Although our results showed that higher ELISA OD values increasethe possibility of the presence of platelet-activating anti-heparin/PF4 antibodies , there is no need for improving ELISA cut-off value for positive result.
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Raschke RA, Gallo T, Curry SC, Whiting T, Padilla-Jones A, Warkentin TE, Puri A. Clinical effectiveness of a Bayesian algorithm for the diagnosis and management of heparin-induced thrombocytopenia. J Thromb Haemost 2017; 15:1640-1645. [PMID: 28622439 DOI: 10.1111/jth.13758] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Indexed: 11/28/2022]
Abstract
Essentials We previously published a diagnostic algorithm for heparin-induced thrombocytopenia (HIT). In this study, we validated the algorithm in an independent large healthcare system. The accuracy was 98%, sensitivity 82% and specificity 99%. The algorithm has potential to improve accuracy and efficiency in the diagnosis of HIT. SUMMARY Background Heparin-induced thrombocytopenia (HIT) is a life-threatening drug reaction caused by antiplatelet factor 4/heparin (anti-PF4/H) antibodies. Commercial tests to detect these antibodies have suboptimal operating characteristics. We previously developed a diagnostic algorithm for HIT that incorporated 'four Ts' (4Ts) scoring and a stratified interpretation of an anti-PF4/H enzyme-linked immunosorbent assay (ELISA) and yielded a discriminant accuracy of 0.97 (95% confidence interval [CI], 0.93-1.00). Objectives The purpose of this study was to validate the algorithm in an independent patient population and quantitate effects that algorithm adherence could have on clinical care. Methods A retrospective cohort comprised patients who had undergone anti-PF4/H ELISA and serotonin release assay (SRA) testing in our healthcare system from 2010 to 2014. We determined the algorithm recommendation for each patient, compared recommendations with the clinical care received, and enumerated consequences of discrepancies. Operating characteristics were calculated for algorithm recommendations using SRA as the reference standard. Results Analysis was performed on 181 patients, 10 of whom were ruled in for HIT. The algorithm accurately stratified 98% of patients (95% CI, 95-99%), ruling out HIT in 158, ruling in HIT in 10 and recommending an SRA in 13 patients. Algorithm adherence would have obviated 165 SRAs and prevented 30 courses of unnecessary antithrombotic therapy for HIT. Diagnostic sensitivity was 0.82 (95% CI, 0.48-0.98), specificity 0.99 (95% CI, 0.97-1.00), PPV 0.90 (95% CI, 0.56-0.99) and NPV 0.99 (95% CI, 0.96-1.00). Conclusions An algorithm incorporating 4Ts scoring and a stratified interpretation of the anti-PF4/H ELISA has good operating characteristics and the potential to improve management of suspected HIT patients.
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Affiliation(s)
- R A Raschke
- Division of Clinical Data Analytics and Decision Support, Department of Medicine, University of Arizona College of Medicine - Phoenix, Phoenix, AZ, USA
- Department of Critical Care Medicine, Banner - University Medical Center Phoenix, Phoenix, AZ, USA
| | - T Gallo
- Division of Clinical Data Analytics and Decision Support, Department of Medicine, University of Arizona College of Medicine - Phoenix, Phoenix, AZ, USA
| | - S C Curry
- Division of Clinical Data Analytics and Decision Support, Department of Medicine, University of Arizona College of Medicine - Phoenix, Phoenix, AZ, USA
- Department of Medical Toxicology, Banner - University Medical Center Phoenix, Phoenix, AZ, USA
| | - T Whiting
- Department of Critical Care Medicine, Banner - University Medical Center Phoenix, Phoenix, AZ, USA
| | - A Padilla-Jones
- Banner Research Institute, Banner - University Medical Center Phoenix, Phoenix, AZ, USA
| | - T E Warkentin
- Department of Pathology and Molecular Medicine, and Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON, Canada
| | - A Puri
- Internal Medicine Residency, University of Arizona College of Medicine Phoenix, Phoenix, AZ, USA
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Rapid immunoassays for diagnosis of heparin-induced thrombocytopenia: Comparison of diagnostic accuracy, reproducibility, and costs in clinical practice. PLoS One 2017; 12:e0178289. [PMID: 28594835 PMCID: PMC5464550 DOI: 10.1371/journal.pone.0178289] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 05/10/2017] [Indexed: 01/01/2023] Open
Abstract
Background Immunoassays are crucial in the work-up of patients with suspected heparin-induced thrombocytopenia (HIT) and rapid tests have been recently developed. However, comparative data on diagnostic accuracy, reproducibility, and analytical costs of different immunoassays in clinical practice are limited. Methods Samples of 179 consecutive patients evaluated for suspected HIT in clinical practice using a polyspecific enzyme-linked immunoabsorbent assay (GTI diagnostics; ELISA) and a rapid particle gel immunoassay (PaGIA), were additionally analysed with a IgG-specific chemiluminescent immunoassay (AcuStar HIT-IgG). Presence of HIT was defined as a positive functional heparin-induced platelet aggregation test. Diagnostic accuracy was determined for low, intermediate and high thresholds as previously established (ELISA: optical density 0.4, 1.3, and 2.0 respectively; PaGIA: positive/negative, titre of 4, titre of 32; AcuStar HIT-IgG: 1.0 U/ml, 2.8, 9.4) and reproducibility was assessed by repeated measurements. Costs of test determination were calculated taking reagents, controls, and working time of technicians according to Swiss health care system into account. Results Data on PaGIA results were available for 171 patients (95.5%), ELISA for 144 patients (80.4%), and AcuStar HIT-IgG for 179 patients (100%). Sensitivity was above 95% for all assays at low and intermediate thresholds. Specificity increased with higher thresholds and was above 90% for all assays with intermediate and high thresholds. Specificity of AcuStar HIT-IgG (92.8%; 95% CI 87.7, 96.2) was significantly higher than PaGIA (83.0%; 95% CI 76.3, 88.5) and higher than ELISA (81.8%, 95% CI 74.2, 88.0) at low threshold (p<0.05). Reproducibility was adequate for all assays. Total costs per test were CHF 51.02 for ELISA, 117.70 for AcuStar HIT-IgG, and 83.13 for PaGIA. Conclusions We observed favourable diagnostic accuracy measures and a high reproducibility for PaGIA and AcuStar HIT-IgG. Implementation into 24-hours-service might improve patient care but the results must be confirmed in other settings and larger populations as well.
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Salter BS, Weiner MM, Trinh MA, Heller J, Evans AS, Adams DH, Fischer GW. Heparin-Induced Thrombocytopenia: A Comprehensive Clinical Review. J Am Coll Cardiol 2017; 67:2519-32. [PMID: 27230048 DOI: 10.1016/j.jacc.2016.02.073] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/03/2016] [Accepted: 02/08/2016] [Indexed: 12/13/2022]
Abstract
Heparin-induced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to low-molecular weight heparin. In this comprehensive review, the authors highlight heparin-induced thrombocytopenia's risk factors, clinical presentation, pathophysiology, diagnostic principles, and treatment. The authors place special emphasis on the management of patients requiring procedures using cardiopulmonary bypass or interventions in the catheterization laboratory. Clinical vigilance of this disease process is important to ensure its recognition, diagnosis, and treatment. Misdiagnosis of the syndrome, as well as misunderstanding of the disease process, continues to contribute to its morbidity and mortality.
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Affiliation(s)
- Benjamin S Salter
- Department of Anesthesiology, Mount Sinai Medical Center, New York, New York.
| | - Menachem M Weiner
- Department of Anesthesiology, Mount Sinai Medical Center, New York, New York
| | - Muoi A Trinh
- Department of Anesthesiology, Mount Sinai Medical Center, New York, New York
| | - Joshua Heller
- Department of Anesthesiology, Mount Sinai Medical Center, New York, New York
| | - Adam S Evans
- Department of Anesthesiology, Mount Sinai Medical Center, New York, New York
| | - David H Adams
- Department of Cardiac Surgery, Mount Sinai Medical Center, New York, New York
| | - Gregory W Fischer
- Department of Anesthesiology, Mount Sinai Medical Center, New York, New York
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Husseinzadeh HD, Gimotty PA, Pishko AM, Buckley M, Warkentin TE, Cuker A. Diagnostic accuracy of IgG-specific versus polyspecific enzyme-linked immunoassays in heparin-induced thrombocytopenia: a systematic review and meta-analysis. J Thromb Haemost 2017; 15:1203-1212. [PMID: 28374939 PMCID: PMC6039095 DOI: 10.1111/jth.13692] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Indexed: 12/17/2022]
Abstract
Essentials Immunoassay specificity varies in heparin-induced thrombocytopenia (HIT) testing. This meta-analysis examined 9 studies that tested samples by both IgG and polyspecific methods. IgG-specific assays confer superior diagnostic accuracy compared with polyspecific assays. These results further support recommendations in favor of IgG-specific testing. SUMMARY Background There are conflicting data on whether the IgG-specific or polyspecific antiplatelet factor 4/heparin (PF4/H) enzyme-linked immunosorbent assay (ELISA) is preferred for the laboratory diagnosis of heparin-induced thrombocytopenia (HIT). Objectives To directly compare diagnostic accuracy of IgG-specific versus polyspecific ELISA in HIT. Patients/Methods A systematic search yielded nine studies comprising 1948 patients with suspected HIT tested by both IgG-specific and polyspecific ELISAs and a reference standard against which the diagnostic accuracy of the ELISAs could be measured. Study quality was assessed by QUADAS-2 criteria. Results There was identical sensitivity for IgG-specific and polyspecific ELISAs (0.97; 95% confidence interval (CI), 0.95-0.99) and superior specificity of IgG-specific compared with polyspecific ELISA (0.87 [0.85-0.88] vs. 0.82 [0.80-0.84], respectively). Performance was similar in subgroups using the serotonin release assay and a single commercial ELISA manufacturer. The negative predictive values of IgG-specific and polyspecific ELISA were similarly high (0.99, [0.99-1.00], but the positive predictive value was superior with IgG-specific compared with polyspecific ELISA (0.56 [0.52-0.61] vs. 0.32 [0.28-0.35], respectively). The positive likelihood ratio (LR) was higher in IgG-specific than polyspecific ELISA, although negative LRs were similar. There was high risk of quality concerns in domains of index test and reference standard. Conclusions The superior diagnostic accuracy of IgG-specific ELISA reinforces the ISTH-SSC recommendation for standardization of laboratory testing for HIT. Likelihood ratios of individual assays may be used in combination with clinical scoring systems as part of an integrated diagnostic algorithm for HIT.
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Affiliation(s)
- H D Husseinzadeh
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - P A Gimotty
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - A M Pishko
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - M Buckley
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - T E Warkentin
- Departments of Pathology and Molecular Medicine, and Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON, Canada
| | - A Cuker
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Favaloro EJ, McCaughan G, Pasalic L. Clinical and laboratory diagnosis of heparin induced thrombocytopenia: an update. Pathology 2017; 49:346-355. [DOI: 10.1016/j.pathol.2017.02.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/17/2017] [Accepted: 02/26/2017] [Indexed: 10/19/2022]
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Abstract
OBJECTIVE Recent studies reveal a high occurrence of overdiagnosis of heparin-induced thrombocytopenia in surgical patients with critical illness. The optimal criteria for diagnosis of heparin-induced thrombocytopenia remain unclear, contributing to unnecessary treatment. We reviewed patients who were admitted to surgical ICUs and were suspected of heparin-induced thrombocytopenia to identify how often patients were correctly treated. DESIGN In this clinical prospective study, data were collected including age, sex, antiplatelet factor 4/heparin enzyme-linked immunosorbent assay, serotonin release assay, and Warkentin 4Ts scores. Heparin-induced thrombocytopenia-positive patients were defined as those with both positive antiplatelet factor 4/heparin enzyme-linked immunosorbent assay (optical density, ≥ 0.40) and positive serotonin release assay results. SETTING Urban tertiary medical center. PATIENTS Patients admitted to the surgical and cardiac ICU who were presumed to have heparin-induced thrombocytopenia and underwent antiplatelet factor 4/heparin enzyme-linked immunosorbent assay and serotonin release assay testing between January 1, 2011, and August 1, 2014. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS A total of 135 patients had 4Ts, antiplatelet factor 4/heparin enzyme-linked immunosorbent assay, and serotonin release assay scores. A total of 11 patients (8.1%) had positive serotonin release assay and 80 patients had positive antiplatelet factor 4/heparin enzyme-linked immunosorbent assay; 10 patients were identified as heparin-induced thrombocytopenia positive. Positive serotonin release assay was noted in nine of 11 patients (81.8%) with antiplatelet factor 4/heparin enzyme-linked immunosorbent assay optical density greater than or equal to 2.0, compared with one of 22 patients (4.5%) with optical density values of 0.85-1.99, and one of 102 patients (1.0%) with optical density values of 0-0.84. Out of 135 patients, 29 patients (21.5%) received treatment with argatroban, lepirudin, or fondaparinux: 10 of 10 heparin-induced thrombocytopenia-positive patients (100%) compared with 19 of 125 heparin-induced thrombocytopenia-negative patients (15%). CONCLUSIONS Overtreatment of heparin-induced thrombocytopenia in the surgical ICU continues even with recent increased caution encouraging a higher antiplatelet factor 4/heparin enzyme-linked immunosorbent assay optical density threshold before initiating treatment. More stringent criteria should be used to determine when to order serologic testing and when the results of such testing should prompt a change in anticoagulant treatment. If antiplatelet factor 4/heparin enzyme-linked immunosorbent assay is used to consider immediate treatment, an optical density greater than or equal to 2.0 may be a more appropriate threshold.
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Welsby IJ, Krakow EF, Heit JA, Williams EC, Arepally GM, Bar-Yosef S, Kong DF, Martinelli S, Dhakal I, Liu WW, Krischer J, Ortel TL. The association of anti-platelet factor 4/heparin antibodies with early and delayed thromboembolism after cardiac surgery. J Thromb Haemost 2017; 15:57-65. [PMID: 27714919 PMCID: PMC5280211 DOI: 10.1111/jth.13533] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Indexed: 12/18/2022]
Abstract
Essentials We evaluated antibody status, thromboembolism and survival after cardiac surgery. Positive antibody tests are common - over 50% are seropositive at 30 days. Seropositivity did not increase thromboembolism or impair survival after cardiac surgery. Results show heparin induced thrombocytopenia antibody screening after surgery is not warranted. SUMMARY Background Heparin-induced thrombocytopenia (HIT) is a prothrombotic response to heparin therapy with platelet-activating, anti-platelet factor 4 (PF4)/heparin antibodies leading to thrombocytopenia associated with thromboembolism. Objective We tested the hypothesis that anti-PF4/heparin antibodies are associated with thromboembolism after cardiac surgery. Methods This multicenter, prospective cohort study collected laboratory and clinical data up to 30 days after surgery and longer-term clinical follow-up data. The primary outcome variable combined new arterial or venous thromboembolic complications (TECs) with all-cause death until 90 days after surgery. Laboratory analyses included platelet counts and anti-PF4/heparin antibody titers (GTI ELISA), with a confirmatory excess heparin step and serotonin release assay. Chi-square testing was used to test the relationship between our outcome and HIT antibody seropositivity. Results Initially, 1021 patients were enrolled between August 2006 and May 2009, and follow-up was completed in December 2014. Seropositivity defined by OD > 0.4 was common, being almost 20% preoperatively, > 30% by discharge, and > 60% by day 30. Death (1.7% within 30 days) or TECs (69 in total) were more likely if the partient was seronegative (OD < 0.4), but positivity defined by OD > 1.0 or including an excess heparin confirmatory step resulted in equal incidence of death or TECs, whether the patient was seronegative or seropositive. Incorporating the serotonin release assay for platelet-activating antibodies did not alter these findings. Conclusions Seropositivity for anti-PF4/heparin antibodies does not increase the risk of death or thromboembolism after cardiac surgery. Screening is not indicated, and seropositivity should only be interpreted in the context of clinical evidence for HIT. TRIAL REGISTRATION Duke IRB Protocol #00010736.
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Affiliation(s)
- I J Welsby
- Department of Anesthesiology and Critical Care, Durham, NC, USA
| | - E F Krakow
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - J A Heit
- Department of Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Durham, NC, USA
| | - E C Williams
- Department of Medicine, Division of Hematology, University of Wisconsin, Durham, NC, USA
| | - G M Arepally
- Department of Medicine, Division of Hematology, Duke University Medical Center, Durham, NC, USA
| | - S Bar-Yosef
- Department of Anesthesiology, Durham VA Medical Center, Durham, NC, USA
| | - D F Kong
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - S Martinelli
- Department of Anesthesiology, University of North Carolina, Durham, NC, USA
| | - I Dhakal
- Department of Biostatistics & Bioinformatics, Duke University Medical Center, Durham, NC, USA
| | - W W Liu
- Department of Biostatistics & Bioinformatics, Duke University Medical Center, Durham, NC, USA
| | - J Krischer
- Pediatric Epidemiology Center, University of South Florida Morsani College of Medicine, Durham, NC, USA
| | - T L Ortel
- Department of Pathology, Duke University Medical Center, Durham, NC, USA
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Safe bridging to warfarin in heparin-induced thrombocytopenia. Thromb Res 2016; 144:226-8. [PMID: 27363624 DOI: 10.1016/j.thromres.2016.06.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 06/21/2016] [Indexed: 11/21/2022]
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Bakchoul T. An update on heparin-induced thrombocytopenia: diagnosis and management. Expert Opin Drug Saf 2016; 15:787-97. [DOI: 10.1517/14740338.2016.1165667] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Tamam Bakchoul
- Institute for Immunology and Transfusion Medicine, Universitätsmedizin Greifswald, Greifswald, Germany
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Abstract
Heparin induced thrombocytopenia (HIT) is a pro-thrombotic and potentially fatal complication of heparin therapy. Its diagnosis rests on high clinical probability and the laboratory demonstration of anti-PF4/heparin antibodies. The high prevalence of thrombocytopenia in hospitalized patients and the high sensitivity but low specificity of immunoassays for HIT antibodies can lead to over-testing and over-diagnosis. We conducted a study to review HIT screening practices in a tertiary care setting. We reviewed 63 consecutive patients undergoing testing for anti-PF4/heparin antibodies over 3 months. Pre-test probability for HIT was calculated using the 4T score. Sixty three patients underwent testing for anti-PF4/heparin antibodies. Twenty one had been admitted for cardiovascular surgery, 5 for other surgery and 35 for non-surgical indications. Twenty nine patients (46 %) had low pre- test probability, twenty three (36.5 %) had intermediate probability, and eleven (17.4 %) had high pre-test probability of having HIT. Anti-PF4/heparin ELISA was positive in 8 of 63 patients. SRA was ordered for 16 patients and was positive in 5. Only five patients were diagnosed and treated for HIT. Over-testing for HIT is highly prevalent in a tertiary care setting. This increases cost and exposes patients to expensive anti-coagulation with its attendant risk of hemorrhage. The 4Ts score has been shown to have high sensitivity and may be used to rule out HIT in most situations, although its utility depends on subjective analysis. Consistently applying this in practice could minimize over-testing and facilitate safer, cost-effective care.
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Maličev E, Kozak M, Rožman P. Evaluation of a flow cytometric assay for the confirmation of heparin-induced thrombocytopenia. Int J Lab Hematol 2016; 38:240-5. [PMID: 26991642 DOI: 10.1111/ijlh.12475] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 01/04/2016] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Heparin-induced thrombocytopenia (HIT) is an immune-mediated thrombocytopenia associated with heparin therapy. The diagnosis consists of a combination of pretest probability and laboratory testing. The routinely available laboratory antigen binding assays for the detection of specific antibodies have a low HIT-positive predictive value; therefore, to exclude false-positive results, one of the functional assays should be performed. Functional assays evaluate the ability of heparin/PF4 antibodies to activate the platelets. The aim of our study was to validate the flow cytometric functional assay, based on the use of anti-CD61 and anti-CD62 antibodies, as a suitable diagnostic test for HIT. METHODS Sera from patients with a clinical suspicion of HIT were previously analyzed with screening IgG-specific ELISA, and 41 of those which were positive were selected for the functional assay. RESULTS Our results were compared to another functional assay - the HIPA (heparin-induced platelet aggregation assay). The diagnostic specificity of the flow cytometric assay was calculated based on HIPA results and was 83%. CONCLUSION Performing this functional test after the screening assay could significantly improve the specificity of HIT testing as heparin/PF4 antibodies are often not clinically significant.
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Affiliation(s)
- E Maličev
- Blood Transfusion Centre of Slovenia, Ljubljana, Slovenia
| | - M Kozak
- University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - P Rožman
- Blood Transfusion Centre of Slovenia, Ljubljana, Slovenia
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Reducing the hospital burden of heparin-induced thrombocytopenia: impact of an avoid-heparin program. Blood 2016; 127:1954-9. [PMID: 26817956 DOI: 10.1182/blood-2015-07-660001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 01/13/2016] [Indexed: 12/22/2022] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is an adverse drug reaction occurring in up to 5% of patients exposed to unfractionated heparin (UFH). We examined the impact of a hospital-wide strategy for avoiding heparin on the incidence of HIT, HIT with thrombosis (HITT), and HIT-related costs. The Avoid-Heparin Initiative, implemented at a tertiary care hospital in Toronto, Ontario, Canada, since 2006, involved replacing UFH with low-molecular-weight heparin (LMWH) for prophylactic and therapeutic indications. Consecutive cases with suspected HIT from 2003 through 2012 were reviewed. Rates of suspected HIT, adjudicated HIT, and HITT, along with HIT-related expenditures were compared in the pre-intervention (2003-2005) and the avoid-heparin (2007-2012) phases. The annual rate of suspected HIT decreased 42%, from 85.5 per 10 000 admissions in the pre-intervention phase to 49.0 per 10 000 admissions in the avoid-heparin phase ( ITALIC! P< .001). The annual rate of patients with a positive HIT assay decreased 63% from 16.5 to 6.1 per 10 000 admissions ( ITALIC! P< .001), adjudicated HIT decreased 79% from 10.7 to 2.2 per 10 000 admissions ( ITALIC! P< .001), and HITT decreased 91% from 4.6 to 0.4 per 10 000 admissions ( ITALIC! P< .001). Hospital HIT-related expenditures decreased by $266 938 per year in the avoid-heparin phase. To the best of our knowledge, this is the first study demonstrating the success and feasibility of a hospital-wide HIT prevention strategy.
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Sun L, Gimotty PA, Lakshmanan S, Cuker A. Diagnostic accuracy of rapid immunoassays for heparin-induced thrombocytopenia. A systematic review and meta-analysis. Thromb Haemost 2016; 115:1044-55. [PMID: 26763074 DOI: 10.1160/th15-06-0523] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 12/03/2015] [Indexed: 01/15/2023]
Abstract
The platelet factor 4/heparin ELISA has limited specificity for heparin-induced thrombocytopenia (HIT) and frequently does not provide same-day results. Rapid immunoassays (RIs) have been developed which provide results in 30 minutes or less. We conducted a systematic review and meta-analysis to evaluate the diagnostic accuracy of RIs for HIT. We searched the literature for studies in which samples from patients with suspected HIT were tested using a RI and a functional assay against which the performance of the RI could be measured. We performed sensitivity analyses of studies that directly compared different RIs with each other and with ELISAs. Estimates of sensitivity and specificity for each RI were calculated. Twenty-three articles, collectively involving six different RIs, met eligibility criteria. All RIs exhibited high sensitivity (0.96 to 1.00); there was wider variability in specificity (0.68 to 0.94). Specificity of the IgG-specific chemiluminescent assay (IgG-CA) was greater than the polyspecific chemiluminescent assay [0.94 (95 %CI 0.89-0.99) vs 0.82 (0.77-0.87)]. The particle gel immunoassay demonstrated greater specificity than the polyspecific ELISA [0.96 (0.95-0.97) vs 0.91 (0.89-0.92)]. The IgG-CA and lateral flow immunoassay [0.94 (0.91-0.97)] exhibited greater specificity than the IgG-specific ELISA [0.86 (0.82-0.90)]. Given their high sensitivity and rapid turnaround time, RIs are a reliable means of excluding HIT at the point-of-care in patients with low or intermediate clinical probability. Additionally, some RIs have greater specificity than HIT ELISAs. In summary, IgG-specific RIs appear to have improved diagnostic accuracy compared with ELISAs in patients with suspected HIT and may reduce misdiagnosis and overtreatment.
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Affiliation(s)
| | | | | | - Adam Cuker
- Adam Cuker, MD, MS, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA, Tel.: +1 215 615 6555, Fax: +1 215 615 6599, E-mail:
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Diagnostic value of immunoassays for heparin-induced thrombocytopenia: a systematic review and meta-analysis. Blood 2015; 127:546-57. [PMID: 26518436 DOI: 10.1182/blood-2015-07-661215] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 10/27/2015] [Indexed: 01/20/2023] Open
Abstract
Immunoassays are essential in the workup of patients with suspected heparin-induced thrombocytopenia. However, the diagnostic accuracy is uncertain with regard to different classes of assays, antibody specificities, thresholds, test variations, and manufacturers. We aimed to assess diagnostic accuracy measures of available immunoassays and to explore sources of heterogeneity. We performed comprehensive literature searches and applied strict inclusion criteria. Finally, 49 publications comprising 128 test evaluations in 15 199 patients were included in the analysis. Methodological quality according to the revised tool for quality assessment of diagnostic accuracy studies was moderate. Diagnostic accuracy measures were calculated with the unified model (comprising a bivariate random-effects model and a hierarchical summary receiver operating characteristics model). Important differences were observed between classes of immunoassays, type of antibody specificity, thresholds, application of confirmation step, and manufacturers. Combination of high sensitivity (>95%) and high specificity (>90%) was found in 5 tests only: polyspecific enzyme-linked immunosorbent assay (ELISA) with intermediate threshold (Genetic Testing Institute, Asserachrom), particle gel immunoassay, lateral flow immunoassay, polyspecific chemiluminescent immunoassay (CLIA) with a high threshold, and immunoglobulin G (IgG)-specific CLIA with low threshold. Borderline results (sensitivity, 99.6%; specificity, 89.9%) were observed for IgG-specific Genetic Testing Institute-ELISA with low threshold. Diagnostic accuracy appears to be inadequate in tests with high thresholds (ELISA; IgG-specific CLIA), combination of IgG specificity and intermediate thresholds (ELISA, CLIA), high-dose heparin confirmation step (ELISA), and particle immunofiltration assay. When making treatment decisions, clinicians should be a aware of diagnostic characteristics of the tests used and it is recommended they estimate posttest probabilities according to likelihood ratios as well as pretest probabilities using clinical scoring tools.
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Gupta S, Tiruvoipati R, Green C, Botha J, Tran H. Heparin induced thrombocytopenia in critically ill: Diagnostic dilemmas and management conundrums. World J Crit Care Med 2015; 4:202-212. [PMID: 26261772 PMCID: PMC4524817 DOI: 10.5492/wjccm.v4.i3.202] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 02/25/2015] [Accepted: 07/14/2015] [Indexed: 02/06/2023] Open
Abstract
Thrombocytopenia is often noted in critically ill patients. While there are many reasons for thrombocytopenia, the use of heparin and its derivatives is increasingly noted to be associated with thrombocytopenia. Heparin induced thrombocytopenia syndrome (HITS) is a distinct entity that is characterised by the occurrence of thrombocytopenia in conjunction with thrombotic manifestations after exposure to unfractionated heparin or low molecular weight heparin. HITS is an immunologic disorder mediated by antibodies to heparin-platelet factor 4 (PF4) complex. HITS is an uncommon cause of thrombocytopenia. Reported incidence of HITS in patients exposed to heparin varies from 0.2% to up to 5%. HITS is rare in ICU populations, with estimates varying from 0.39%-0.48%. It is a complex problem which may cause diagnostic dilemmas and management conundrum. The diagnosis of HITS centers around detection of antibodies against PF4-heparin complexes. Immunoassays performed by most pathology laboratories detect the presence of antibodies, but do not reveal whether the antibodies are pathological. Platelet activation assays demonstrate the presence of clinically relevant antibodies, but only a minority of laboratories conduct them. Several anticoagulants are used in management of HITS. In this review we discuss the incidence, pathogenesis, diagnosis and management of HITS.
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Doré M, Frenette AJ, Chagnon I, Routhier N, Williamson D. Interrater agreement for two systems used to determine the probability of heparin-induced thrombocytopenia. Am J Health Syst Pharm 2015; 71:2045-52. [PMID: 25404596 DOI: 10.2146/ajhp130711] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
PURPOSE The interrater reliability of the 4T's method and the HIT expert probability (HEP) score for clinical evaluation of suspected heparin-induced thrombocytopenia (HIT) was investigated. METHODS Patients hospitalized over a three-year period who were tested for HIT via anti-platelet factor 4 (anti-PF4) antigen assay were identified using laboratory data; 127 patient cases met the study inclusion criteria. Nine clinical pharmacists with expertise in HIT management evaluated the 127 cases using two pretest scoring systems: the 4T's score and the HEP score. Each case was independently evaluated using both 4T's and HEP scores. The primary endpoint was interrater agreement of overall 4T's and HEP scores and individual item scores. RESULTS Raw agreement of values assigned by the two raters for each of the four items comprising the 4T's score ranged from 0.54 to 0.86, with agreement of 0.63 for final patient categorizations. Raw agreement of rater weightings of the eight HEP scoring items ranged from 0.34 to 1.0; for dichotomization of patients at the suggested screening cutoff value (>2.0), agreement was 0.65. Kappa coefficients were 0.15-0.45 for 4T's item scores and 0.17-0.70 for HEP score item scores. With both scoring systems, low rater agreement mainly related to determination of the timing of thrombocytopenia and possible other causes of the disorder. CONCLUSION In a retrospective study, inter-rater agreement in scoring of HIT probability via the 4T's and HEP scoring systems was relatively low. The HEP score did not increase interrater reliability or correlation with anti-PF4 antibodies compared with the 4T's score.
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Affiliation(s)
- Maxime Doré
- Maxime Doré, B.Pharm., M.Sc., is Pharmacist, Department of Pharmacy, Hôpital du Sacré-Coeur de Montréal, Montréal, Quebec, Canada. Anne Julie Frenette, B.Pharm., M.Sc., is Assistant Clinical Professor, Associate Researcher, and Critical Care Pharmacist, Department of Pharmacy and Research Center, Hôpital du Sacré-Coeur de Montréal, and Faculty of Pharmacy, University of Montreal. Isabelle Chagnon, M.D., FRCPC, is Specialist, Internal Medicine, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and Clinical Professor of Medicine, Faculty of Medicine, University of Montreal. Nathalie Routhier, M.D., M.Sc., FRCPC, is Specialist, Internal Medicine, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and Clinical Professor of Medicine, Faculty of Medicine, University of Montreal. David Williamson, B.Pharm., M.Sc., BCPS, is Associate Researcher and Critical Care Pharmacist, Department of Pharmacy and Research Center, Hôpital du Sacré-Coeur de Montréal, and Associate Clinical Professor, Faculty of Pharmacy, University of Montreal.
| | - Anne Julie Frenette
- Maxime Doré, B.Pharm., M.Sc., is Pharmacist, Department of Pharmacy, Hôpital du Sacré-Coeur de Montréal, Montréal, Quebec, Canada. Anne Julie Frenette, B.Pharm., M.Sc., is Assistant Clinical Professor, Associate Researcher, and Critical Care Pharmacist, Department of Pharmacy and Research Center, Hôpital du Sacré-Coeur de Montréal, and Faculty of Pharmacy, University of Montreal. Isabelle Chagnon, M.D., FRCPC, is Specialist, Internal Medicine, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and Clinical Professor of Medicine, Faculty of Medicine, University of Montreal. Nathalie Routhier, M.D., M.Sc., FRCPC, is Specialist, Internal Medicine, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and Clinical Professor of Medicine, Faculty of Medicine, University of Montreal. David Williamson, B.Pharm., M.Sc., BCPS, is Associate Researcher and Critical Care Pharmacist, Department of Pharmacy and Research Center, Hôpital du Sacré-Coeur de Montréal, and Associate Clinical Professor, Faculty of Pharmacy, University of Montreal
| | - Isabelle Chagnon
- Maxime Doré, B.Pharm., M.Sc., is Pharmacist, Department of Pharmacy, Hôpital du Sacré-Coeur de Montréal, Montréal, Quebec, Canada. Anne Julie Frenette, B.Pharm., M.Sc., is Assistant Clinical Professor, Associate Researcher, and Critical Care Pharmacist, Department of Pharmacy and Research Center, Hôpital du Sacré-Coeur de Montréal, and Faculty of Pharmacy, University of Montreal. Isabelle Chagnon, M.D., FRCPC, is Specialist, Internal Medicine, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and Clinical Professor of Medicine, Faculty of Medicine, University of Montreal. Nathalie Routhier, M.D., M.Sc., FRCPC, is Specialist, Internal Medicine, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and Clinical Professor of Medicine, Faculty of Medicine, University of Montreal. David Williamson, B.Pharm., M.Sc., BCPS, is Associate Researcher and Critical Care Pharmacist, Department of Pharmacy and Research Center, Hôpital du Sacré-Coeur de Montréal, and Associate Clinical Professor, Faculty of Pharmacy, University of Montreal
| | - Nathalie Routhier
- Maxime Doré, B.Pharm., M.Sc., is Pharmacist, Department of Pharmacy, Hôpital du Sacré-Coeur de Montréal, Montréal, Quebec, Canada. Anne Julie Frenette, B.Pharm., M.Sc., is Assistant Clinical Professor, Associate Researcher, and Critical Care Pharmacist, Department of Pharmacy and Research Center, Hôpital du Sacré-Coeur de Montréal, and Faculty of Pharmacy, University of Montreal. Isabelle Chagnon, M.D., FRCPC, is Specialist, Internal Medicine, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and Clinical Professor of Medicine, Faculty of Medicine, University of Montreal. Nathalie Routhier, M.D., M.Sc., FRCPC, is Specialist, Internal Medicine, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and Clinical Professor of Medicine, Faculty of Medicine, University of Montreal. David Williamson, B.Pharm., M.Sc., BCPS, is Associate Researcher and Critical Care Pharmacist, Department of Pharmacy and Research Center, Hôpital du Sacré-Coeur de Montréal, and Associate Clinical Professor, Faculty of Pharmacy, University of Montreal
| | - David Williamson
- Maxime Doré, B.Pharm., M.Sc., is Pharmacist, Department of Pharmacy, Hôpital du Sacré-Coeur de Montréal, Montréal, Quebec, Canada. Anne Julie Frenette, B.Pharm., M.Sc., is Assistant Clinical Professor, Associate Researcher, and Critical Care Pharmacist, Department of Pharmacy and Research Center, Hôpital du Sacré-Coeur de Montréal, and Faculty of Pharmacy, University of Montreal. Isabelle Chagnon, M.D., FRCPC, is Specialist, Internal Medicine, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and Clinical Professor of Medicine, Faculty of Medicine, University of Montreal. Nathalie Routhier, M.D., M.Sc., FRCPC, is Specialist, Internal Medicine, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and Clinical Professor of Medicine, Faculty of Medicine, University of Montreal. David Williamson, B.Pharm., M.Sc., BCPS, is Associate Researcher and Critical Care Pharmacist, Department of Pharmacy and Research Center, Hôpital du Sacré-Coeur de Montréal, and Associate Clinical Professor, Faculty of Pharmacy, University of Montreal
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Stipić F, Pletikapić G, Jakšić Ž, Frkanec L, Zgrablić G, Burić P, Lyons DM. Application of Functionalized Lanthanide-Based Nanoparticles for the Detection of Okadaic Acid-Specific Immunoglobulin G. J Phys Chem B 2015; 119:1259-64. [DOI: 10.1021/jp506382w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Filip Stipić
- Center
for Marine Research, Ruđer Bošković Institute, G. Paliaga
5, 52210 Rovinj, Croatia
| | | | - Željko Jakšić
- Center
for Marine Research, Ruđer Bošković Institute, G. Paliaga
5, 52210 Rovinj, Croatia
| | | | - Goran Zgrablić
- Time
Resolved X-ray Spectroscopy Laboratory, Elettra-Sincrotrone Trieste, 34149 Basovizza, Italy
| | - Petra Burić
- Center
for Marine Research, Ruđer Bošković Institute, G. Paliaga
5, 52210 Rovinj, Croatia
| | - Daniel M. Lyons
- Center
for Marine Research, Ruđer Bošković Institute, G. Paliaga
5, 52210 Rovinj, Croatia
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Prevalence and clinical implications of anti-PF4/heparin antibodies in intensive care patients: a prospective observational study. J Thromb Thrombolysis 2014; 39:60-7. [DOI: 10.1007/s11239-014-1105-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Leroux D, Hezard N, Lebreton A, Bauters A, Suchon P, de Maistre E, Biron C, Huisse MG, Ternisien C, Voisin S, Gruel Y, Pouplard C. Prospective evaluation of a rapid nanoparticle-based lateral flow immunoassay (STic Expert(®) HIT) for the diagnosis of heparin-induced thrombocytopenia. Br J Haematol 2014; 166:774-82. [PMID: 24815503 DOI: 10.1111/bjh.12939] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 03/19/2014] [Indexed: 12/21/2022]
Abstract
A rapid lateral flow immunoassay (LFIA) (STic Expert(®) HIT), recently developed for the diagnosis of heparin-induced thrombocytopenia (HIT), was evaluated in a prospective multicentre cohort of 334 consecutive patients. The risk of HIT was estimated by the 4Ts score as low, intermediate and high in 28·7%, 61·7% and 9·6% of patients, respectively. Definite HIT was diagnosed in 40 patients (12·0%) with positive results on both enzyme-linked immunosorbent assay (Asserachrom(®) HPIA IgG) and serotonin release assay. The inter-reader reproducibility of results obtained was excellent (kappa ratio > 0·9). The negative predictive value of LFIA with plasma samples was 99·6% with a negative likelihood ratio (LR) of 0·03, and was comparable to those of the particle gel immunoassay (H/PF4-PaGIA(®) ) performed in 124 cases. Positive predictive value and positive LR were 44·4% and 5·87, respectively, and the results were similar for serum samples. The probability of HIT in intermediate risk patients decreased from 11·2% to 0·4% when the LFIA result was negative and increased to 42·5% when it was positive. In conclusion, the STic Expert(®) HIT combined with the 4Ts score is a reliable tool to rule out the diagnosis of HIT.
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Affiliation(s)
- Dorothée Leroux
- Haemostasis Laboratory and UMR CNRS 7292, Hôpital Trousseau and Université François Rabelais Tours, Tours, France
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Kopolovic I, Warkentin TE. Progressive thrombocytopenia after cardiac surgery in a 67-year-old man. CMAJ 2014; 186:929-33. [PMID: 24756626 DOI: 10.1503/cmaj.131449] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Ilana Kopolovic
- Department of Medicine (Kopolovic), University of Toronto, Toronto, Ont.; Pathology and Molecular Medicine (Warkentin), Hamilton Regional Laboratory Medicine Program, McMaster University, Hamilton, Ont.
| | - Theodore E Warkentin
- Department of Medicine (Kopolovic), University of Toronto, Toronto, Ont.; Pathology and Molecular Medicine (Warkentin), Hamilton Regional Laboratory Medicine Program, McMaster University, Hamilton, Ont
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Bakchoul T, Zöllner H, Greinacher A. Current insights into the laboratory diagnosis of HIT. Int J Lab Hematol 2014; 36:296-305. [DOI: 10.1111/ijlh.12236] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 03/12/2014] [Indexed: 11/30/2022]
Affiliation(s)
- T. Bakchoul
- Department of Immunology and Transfusion Medicine; Universitätsmedizin Greifswald; Greifswald Germany
| | - H. Zöllner
- Department of Immunology and Transfusion Medicine; Universitätsmedizin Greifswald; Greifswald Germany
| | - A. Greinacher
- Department of Immunology and Transfusion Medicine; Universitätsmedizin Greifswald; Greifswald Germany
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40
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Schindewolf M, Steindl J, Beyer-Westendorf J, Schellong S, Dohmen PM, Brachmann J, Madlener K, Pötzsch B, Klamroth R, Hankowitz J, Banik N, Eberle S, Kropff S, Müller MM, Lindhoff-Last E. Frequent off-label use of fondaparinux in patients with suspected acute heparin-induced thrombocytopenia (HIT)--findings from the GerHIT multi-centre registry study. Thromb Res 2014; 134:29-35. [PMID: 24703295 DOI: 10.1016/j.thromres.2014.03.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 03/05/2014] [Accepted: 03/11/2014] [Indexed: 10/25/2022]
Abstract
INTRODUCTION In life-threatening immune heparin-induced thrombocytopenia (HIT), treatment with an approved non-heparin anticoagulant is essential. However, off-label use with fondaparinux has been reported in the literature. The study aim was to collect data on "real-life" management of patients with suspected acute HIT regarding diagnostic and therapeutic strategies. PATIENTS AND METHODS In a national multi-centre registry study, patients with a 4T's HIT-probability score of ≥ 4 points and treatment with at least one dose of (A)rgatroban, (L)epirudin, (D)anaparoid, or (F)ondaparinux were retrospectively evaluated. RESULTS Of 195 patients, the 4T's scores were 4/5/6/7/8 points in 46 (23.6%)/50 (25.6%)/74 (38.0%)/13 (6.7%)/7 (3.6%) patients, respectively. During heparin therapy, 47 (24.1%) thromboembolic events, 5 (2.6%) skin lesions, 1 (0.5%) amputation, 24 (12.3%) Hb-relevant bleedings, and 2 (1.0%) fatalities occurred. A functional heparin-induced platelet activation assay was performed in 96.9%, a platelet factor 4/heparin-dependent enzyme immunoassay in 89.2%, a particle gel immunoassay in 12.3%, and a serotonin-release assay in none of the patients. Argatroban was used in 16.4%, lepirudin in 2.1%, danaparoid in 23.6%, fondaparinux in 40.0% of the patients; the sequential therapy strata were: AF (5.6%), DA (5.6%), DF (2.6%), DL (2.1%), ADF (1.5%), and DFL (0.5%). CONCLUSIONS The current diagnostic laboratory strategy for suspected HIT is mostly (>96%) based on the recommended 2-step strategy (immunoassay plus functional assay). However, there is a wide fondaparinux off-label use (up to 50.3%) for suspected HIT, even in those patients with a high clinical pretest probability. Efficacy and safety of fondaparinux for HIT-treatment require further evaluation.
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Affiliation(s)
- Marc Schindewolf
- Department of Internal Medicine, Division of Vascular Medicine/Haemostaseology, Goethe University Hospital, Frankfurt/M., Germany.
| | - Julia Steindl
- Department of Internal Medicine, Division of Vascular Medicine/Haemostaseology, Goethe University Hospital, Frankfurt/M., Germany
| | - Jan Beyer-Westendorf
- Department of Medicine III, Division of Angiology, University Hospital Carl Gustav Carus Dresden, Dresden, Germany
| | - Sebastian Schellong
- Medical Department II, Municipal Hospital Dresden Friedrichstadt, Dresden, Germany
| | - Pascal Maria Dohmen
- Department of Cardiovascular Surgery, Charité Hospital, Medical University Berlin, Berlin, Germany
| | - Johannes Brachmann
- II. Medical Clinic, Department of Cardiology, Klinikum Coburg, Coburg, Germany
| | - Katharina Madlener
- Department of Haemostaseology and Transfusion Medicine, Kerckhoff-Klinik, Bad Nauheim, Germany
| | - Bernd Pötzsch
- Institute of Experimental Haematology and Transfusion Medicine, University Hospital Bonn, Bonn, Germany
| | - Robert Klamroth
- Department of Internal Medicine, Haemophilia Treatment Centre, Vivantes Klinikum im Friedrichshain Berlin, Berlin, Germany
| | | | - Norbert Banik
- GlaxoSmithKline, Biostatistics & Epidemiology, München, Germany
| | - Sonja Eberle
- GlaxoSmithKline, Biostatistics & Epidemiology, München, Germany
| | - Stefan Kropff
- GlaxoSmithKline, Cardiovascular and Antithrombotics, München, Germany
| | | | - Edelgard Lindhoff-Last
- Department of Internal Medicine, Division of Vascular Medicine/Haemostaseology, Goethe University Hospital, Frankfurt/M., Germany
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Platelet factor 4/heparin-particle gel immunoassay (PaGIA) is a weak method for heparin-induced thrombocytopenia (HIT) evaluation of post cardio-pulmonary bypass surgery patients. J Thromb Thrombolysis 2014; 38:314-20. [DOI: 10.1007/s11239-014-1066-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Multicentric validation of a rapid assay for heparin-induced thrombocytopenia with different specimen types. Blood Coagul Fibrinolysis 2014; 25:6-9. [DOI: 10.1097/mbc.0b013e32836577c8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Hron G, Knutson F, Thiele T, Althaus K, Busemann C, Friesecke S, Greinacher A, Lubenow N. Alternative diagnosis to heparin-induced thrombocytopenia in two critically ill patients despite a positive PF4/heparin-antibody test. Ups J Med Sci 2013; 118:279-84. [PMID: 24102149 PMCID: PMC4190887 DOI: 10.3109/03009734.2013.838811] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Thrombocytopenia can cause diagnostic challenges in patients who have received heparin. Heparin-induced thrombocytopenia (HIT) is often considered in the differential diagnosis, and a positive screening can be mistaken as confirmation of the disorder. We present two patients who both received low-molecular-weight heparin for several days. In the first patient, clinical judgment rejected the suspicion of HIT despite a positive screening assay, and treatment for the alternative diagnosis of post-transfusion purpura was correctly initiated. In the second patient, the inaccurate diagnosis HIT was pursued due to a positive screening assay, while the alternative diagnosis of drug-dependent thrombocytopenia caused by piperacillin/tazobactam was rejected. This resulted in re-exposure to piperacillin/tazobactam which caused a second episode of severe thrombocytopenia. A positive screening assay for platelet factor 4/heparin-antibody should be verified by a functional assay, especially in patients with low pretest probability for HIT.
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Affiliation(s)
- Gregor Hron
- Abteilung für Transfusionsmedizin, Institut für Immunologie und Transfusionsemedizin, Ernst-Moritz-Arndt University Greifswald, Germany
| | - Folke Knutson
- Department of Clinical Immunology and Transfusion Medicine, Uppsala University Hospital, Uppsala, Sweden
| | - Thomas Thiele
- Abteilung für Transfusionsmedizin, Institut für Immunologie und Transfusionsemedizin, Ernst-Moritz-Arndt University Greifswald, Germany
| | - Karina Althaus
- Abteilung für Transfusionsmedizin, Institut für Immunologie und Transfusionsemedizin, Ernst-Moritz-Arndt University Greifswald, Germany
| | - Christoph Busemann
- Klinik für Innere Medizin C, Ernst-Moritz-Arndt University Greifswald, Germany
| | - Sigrun Friesecke
- Klinik für Innere Medizin B, Ernst-Moritz-Arndt University Greifswald, Germany
| | - Andreas Greinacher
- Abteilung für Transfusionsmedizin, Institut für Immunologie und Transfusionsemedizin, Ernst-Moritz-Arndt University Greifswald, Germany
| | - Norbert Lubenow
- Department of Clinical Immunology and Transfusion Medicine, Uppsala University Hospital, Uppsala, Sweden
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Raschke RA, Curry SC, Warkentin TE, Gerkin RD. Improving Clinical Interpretation of the Anti-Platelet Factor 4/Heparin Enzyme-Linked Immunosorbent Assay for the Diagnosis of Heparin-Induced Thrombocytopenia Through the Use of Receiver Operating Characteristic Analysis, Stratum-Specific Likelihood Ratios, and Bayes Theorem. Chest 2013; 144:1269-1275. [DOI: 10.1378/chest.12-2712] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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45
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Thiele T, Selleng K, Selleng S, Greinacher A, Bakchoul T. Thrombocytopenia in the Intensive Care Unit—Diagnostic Approach and Management. Semin Hematol 2013; 50:239-50. [DOI: 10.1053/j.seminhematol.2013.06.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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46
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Nazi I, Arnold DM, Smith JW, Horsewood P, Moore JC, Warkentin TE, Crowther MA, Kelton JG. FcγRIIa proteolysis as a diagnostic biomarker for heparin-induced thrombocytopenia. J Thromb Haemost 2013; 11:1146-53. [PMID: 23551961 DOI: 10.1111/jth.12208] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Indexed: 11/28/2022]
Abstract
BACKGROUND A significant challenge in the management of heparin-induced thrombocytopenia (HIT) patients is making a timely and accurate diagnosis. The readily available enzyme immunoassays (EIAs) have low specificities. In contrast, platelet activation assays have higher specificities, but they are technically demanding and not widely available. In addition, ~ 10% of samples referred for HIT testing are initially classified as indeterminate by the serotonin release assay (SRA), which further delays accurate diagnosis. HIT is characterized by platelet activation, which leads to FcγRIIa proteolysis. This raises the possibility that identification of the proteolytic fragment of FcγRIIa could serve as a surrogate marker for HIT. OBJECTIVES To determine the specificity of platelet FcγRIIa proteolysis induced by sera from patients with HIT, and to correlate the results with those of the SRA. METHODS/PATIENTS Sera from HIT patients and control patients with other thrombocytopenic/prothrombotic disorders were tested for their ability to proteolyse FcγRIIa. The results were correlated with anti-platelet factor 4 (PF4)/heparin antibodies (EIA), and heparin-dependent platelet activation (SRA). RESULTS Only HIT patient samples (20/20) caused heparin-dependent FcγRIIa proteolysis, similar to what was shown by the SRA. None of the samples from the other patient groups or hospital controls caused FcγRIIa proteolysis. Among nine additional samples that tested indeterminate in the SRA, FcγRIIa proteolysis resolved five samples that had a positive anti-PF4/heparin EIA result; three had no FcγRIIa proteolysis, and two were shown to have heparin-dependent FcγRIIa proteolysis CONCLUSIONS This study suggests that heparin-dependent FcγRIIa proteolysis is at least as specific as the SRA for the diagnosis of HIT.
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Affiliation(s)
- I Nazi
- Department of Medicine, Michael G DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada.
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47
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Bakchoul T, Greinacher A. Recent advances in the diagnosis and treatment of heparin-induced thrombocytopenia. Ther Adv Hematol 2013; 3:237-51. [PMID: 23606934 DOI: 10.1177/2040620712443537] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is a drug-mediated, prothrombotic disorder caused by immunization against platelet factor 4 (PF4) after complex formation with heparin or other polyanions. After their binding to PF4/heparin complexes on the platelet surface, HIT antibodies are capable of intravascular platelet activation by cross-linking Fcγ receptor IIA leading to a platelet count decrease and/or thrombosis. Diagnosis of HIT is often difficult. This, and the low specificity of the commercially available immunoassays, leads currently to substantial overdiagnosis of HIT. Timing of onset, the moderate nature of thrombocytopenia, and the common concurrence of thrombosis are very important factors, which help to differentiate HIT from other potential causes of thrombocytopenia. A combination of a clinical pretest scoring system and laboratory investigation is usually necessary to diagnose HIT. Although HIT is considered to be a rare complication of heparin treatment, the very high number of hospital inpatients, and increasingly also hospital outpatients receiving heparin, still result in a considerable number of patients developing HIT. If HIT occurs, potentially devastating complications such as life-threatening thrombosis make it one of the most serious adverse drug reactions. If HIT is strongly suspected, all heparin must be stopped and an alternative nonheparin anticoagulant started at a therapeutic dose to prevent thromboembolic complications. However, the nonheparin alternative anticoagulants bear a considerable bleeding risk, especially if given to patients with thrombocytopenia due to other reasons than HIT. While established drugs for HIT are disappearing from the market (lepirudin, danaparoid), bivalirudin, fondaparinux and potentially the new anticoagulants such as dabigatran, rivaroxaban and apixaban provide new treatment options.
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Affiliation(s)
- Tamam Bakchoul
- Department of Immunology and Transfusion Medicine, Ernst-Moritz-Arndt niversity, Greifswald, Germany
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48
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Lee GM, Arepally GM. Diagnosis and management of heparin-induced thrombocytopenia. Hematol Oncol Clin North Am 2013; 27:541-63. [PMID: 23714311 DOI: 10.1016/j.hoc.2013.02.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder caused by antibodies to platelet factor 4/heparin (PF4/H) complexes. It presents with declining platelet counts 5 to 14 days after heparin administration and results in a predisposition to arterial and venous thrombosis. Establishing the diagnosis of HIT can be extremely challenging. It is essential to conduct a thorough clinical evaluation in addition to laboratory testing to confirm the presence of PF4/H antibodies. Multiple clinical algorithms have been developed to aid the clinician in predicting the likelihood of HIT. Once HIT is recognized, an alternative anticoagulant should be initiated to prevent further complications.
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Affiliation(s)
- Grace M Lee
- Division of Hematology, Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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49
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Antithrombotic therapy in heparin-induced thrombocytopenia: guidelines translated for the clinician. J Thromb Thrombolysis 2013; 34:552-61. [PMID: 22843169 DOI: 10.1007/s11239-012-0785-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Heparin-induced thrombocytopenia (HIT) is a clinicopathologic syndrome initiated by heparin exposure and characterized by thrombocytopenia and paradoxical thrombophilia. HIT is mediated by the formation of antibodies against the platelet factor 4/heparin complex, which leads to platelet activation, thrombin generation, and potentially fatal thrombotic sequelae. The clinical presentation of HIT is variable and can be easily overlooked. Although a number of functional and antigen-based immunoassays have been developed to detect the presence of HIT antibodies, initial diagnosis is often based on recognition of thrombocytopenia in the appropriate clinical context and later confirmed with immunologic testing. Given the serious clinical consequences of HIT, immediate cessation of heparin products and administration of non-heparin anticoagulants are crucial components of treatment. We provide a review of the clinical syndrome and practical summary of treatment recommendations from the most recent 2012 American College of Chest Physicians evidence-based guidelines for the treatment and prevention of HIT.
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50
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Althaus K, Hron G, Strobel U, Abbate R, Rogolino A, Davidson S, Greinacher A, Bakchoul T. Evaluation of automated immunoassays in the diagnosis of heparin induced thrombocytopenia. Thromb Res 2013; 131:e85-90. [DOI: 10.1016/j.thromres.2013.01.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 12/10/2012] [Accepted: 01/02/2013] [Indexed: 10/27/2022]
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