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Arachchillage DJ, Thachil J, Anderson JAM, Baker P, Poles A, Kitchen S, Laffan M. Diagnosis and management of heparin-induced thrombocytopenia: Third edition. Br J Haematol 2024; 204:459-475. [PMID: 38153164 DOI: 10.1111/bjh.19180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/16/2023] [Accepted: 10/19/2023] [Indexed: 12/29/2023]
Affiliation(s)
- Deepa J Arachchillage
- Centre for Haematology, Department of Immunology and Inflammation, Imperial College London, London, UK
- Department of Haematology, Imperial College Healthcare NHS Trust, London, UK
| | - Jecko Thachil
- Department of Haematology, Manchester Royal Infirmary, Manchester, UK
| | - Julia A M Anderson
- Department of Haematology, Edinburgh Royal Infirmary, Edinburgh, Scotland
| | - Peter Baker
- Oxford Haemophilia and Thrombosis Centre, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Anthony Poles
- Bristol NHS Blood and Transplant Centre, Bristol, UK
| | - Steve Kitchen
- Department of Haematology, Royal Hallamshire Hospital, Sheffield, UK
| | - Mike Laffan
- Centre for Haematology, Department of Immunology and Inflammation, Imperial College London, London, UK
- Department of Haematology, Imperial College Healthcare NHS Trust, London, UK
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Thomas C, Ali R, Park I, Kim H, Short S, Kaunfer S, Durai L, Yilmam OA, Shenoy T, Battinelli EM, Al-Samkari H, Leaf DE. Platelet Factor 4 Antibodies and Severe AKI. KIDNEY360 2023; 4:1672-1679. [PMID: 37907435 PMCID: PMC10758522 DOI: 10.34067/kid.0000000000000287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 10/19/2023] [Indexed: 11/02/2023]
Abstract
Key Points Patients testing positive for platelet factor 4 antibodies have a >50% higher odds of developing severe AKI compared with those who test negative. The relationship between platelet factor 4 antibodies and severe AKI was independent of demographics, comorbidities, laboratory values, and severity-of-illness characteristics. Background Heparin-induced thrombocytopenia, which results from production of antibodies that bind to heparin-platelet factor 4 (PF4) complexes, is a hypercoagulable state associated with considerable morbidity and mortality due to thrombotic complications. We investigated whether PF4 antibodies are associated with an increased risk of AKI. Methods We conducted a cohort study of hospitalized adults who underwent testing for PF4 antibodies at two large medical centers in Boston between 2015 and 2021. The primary exposure was PF4 test positivity. The primary outcome was severe AKI, defined by Kidney Disease: Improving Global Outcomes stage 3 as a ≥3-fold increase in serum creatinine or receipt of KRT within 7 days after the PF4 test. We used multivariable logistic regression to adjust for potential confounders. Results A total of 4224 patients were included in our analysis, 469 (11.1%) of whom had a positive PF4 test. Severe AKI occurred in 50 of 469 patients (10.7%) with a positive PF4 test and in 235 of 3755 patients (6.3%) with a negative test (unadjusted odds ratio, 1.79 [95% confidence interval, 1.30 to 2.47]). In multivariable analyses adjusted for demographics, comorbidities, laboratory values, and severity-of-illness characteristics, PF4 test positivity remained associated with a higher risk of severe AKI (adjusted odds ratio, 1.56 [95% confidence interval, 1.10 to 2.20]). Conclusions Among hospitalized adults, the presence of PF4 antibodies is independently associated with a 56% higher odds of developing severe AKI. Additional studies are needed to investigate potential mechanisms that may underlie these findings, such as pathogenic effects of PF4 antibodies on the microvasculature of the kidneys.
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Affiliation(s)
- Charlotte Thomas
- Harvard Medical School, Boston, Massachusetts
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Rafia Ali
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Isabel Park
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Helena Kim
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Samuel Short
- Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Sarah Kaunfer
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Lavanya Durai
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Osman A. Yilmam
- Harvard Medical School, Boston, Massachusetts
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Tushar Shenoy
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Elisabeth M. Battinelli
- Harvard Medical School, Boston, Massachusetts
- Division of Hematology, Brigham and Women's Hospital, Boston, Massachusetts
| | - Hanny Al-Samkari
- Harvard Medical School, Boston, Massachusetts
- Division of Hematology, Massachusetts General Hospital, Boston, Massachusetts
| | - David E. Leaf
- Harvard Medical School, Boston, Massachusetts
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
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Man L, Yount K, Grazioli A, Padmanabhan A, Thiele R, Maitland HS, Mazzeffi M. Recrudescent Heparin-Induced Thrombocytopenia After Therapeutic Plasma Exchange in a Patient Undergoing Thoracic Aortic Replacement. J Cardiothorac Vasc Anesth 2023; 37:2592-2596. [PMID: 37827918 PMCID: PMC10802261 DOI: 10.1053/j.jvca.2023.09.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 08/31/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023]
Affiliation(s)
- Louise Man
- University of Virginia School of Medicine, Department of Medicine, Division of Hematology and Oncology, Charlottesville, VA
| | - Kenan Yount
- University of Virginia School of Medicine, Department of Surgery, Division of Cardiothoracic Surgery, Charlottesville, VA
| | | | - Anand Padmanabhan
- Mayo Clinic College of Medicine, Department of Pathology, Rochester, MN
| | - Robert Thiele
- University of Virginia, Department of Anesthesiology, Charlottesville, VA
| | - Hillary S Maitland
- University of Virginia School of Medicine, Department of Medicine, Division of Hematology and Oncology, Charlottesville, VA
| | - Michael Mazzeffi
- University of Virginia, Department of Anesthesiology, Charlottesville, VA.
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May J, Westbrook B, Cuker A. Heparin-induced thrombocytopenia: An illustrated review. Res Pract Thromb Haemost 2023; 7:100283. [PMID: 37601013 PMCID: PMC10439402 DOI: 10.1016/j.rpth.2023.100283] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/25/2023] [Accepted: 05/31/2023] [Indexed: 08/22/2023] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is an immune-mediated adverse drug effect from unfractionated or low-molecular-weight heparin that results in thrombocytopenia and potentially catastrophic thrombosis. HIT occurs due to the development of platelet-activating antibodies against multimolecular complexes of platelet factor 4 and heparin. Given the frequency of thrombocytopenia and heparin use among hospitalized patients, calculation of the 4Ts Score is recommended to identify patients at increased likelihood of HIT and direct further evaluation. In patients with an intermediate or high probability 4Ts Score, an immunoassay and functional assay are recommended to confirm or refute the diagnosis of HIT. Heparin avoidance and initiation of nonheparin anticoagulation are the mainstays of acute HIT management. In this illustrated review, we provide visual summaries of the diagnosis and management of HIT, highlighting connections between pathophysiology and clinical care as well as summarizing efforts in quality improvement in the field. We further emphasize common pitfalls and pearls in diagnosis and management to encourage evidence-based care. We include graphical representation of the unique challenges of HIT with cardiopulmonary bypass and also delineate autoimmune HIT and its subtypes.
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Affiliation(s)
- Jori May
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Brian Westbrook
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Adam Cuker
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Pishko A, Cuker A. Early-onset heparin-induced thrombocytopenia after cardiac surgery: Should we lose sleep? J Thromb Haemost 2022; 20:2491-2493. [PMID: 36271465 DOI: 10.1111/jth.15840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 12/01/2022]
Affiliation(s)
- Allyson Pishko
- Division of Hematology & Oncology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Adam Cuker
- Division of Hematology & Oncology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Pathology & Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Antibodies against Platelet Factor 4 and Their Associated Pathologies: From HIT/HITT to Spontaneous HIT-Like Syndrome, to COVID-19, to VITT/TTS. Antibodies (Basel) 2022; 11:antib11010007. [PMID: 35225866 PMCID: PMC8883896 DOI: 10.3390/antib11010007] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/20/2021] [Accepted: 01/19/2022] [Indexed: 02/06/2023] Open
Abstract
Antibodies against platelet factor 4 (PF4), a protein released from alpha-granules of activated platelets, may cause a number of pathophysiological conditions. The most commonly known is heparin-induced thrombocytopenia (HIT), which develops in a small proportion of people treated with the anticoagulant drug heparin. Notably, PF4 binds with high affinity to heparin, and in HIT, complexes of PF4/H may, in a small proportion of susceptible patients, trigger the development of anti-PF4 antibodies and subsequent platelet activation and aggregation, ultimately leading to the development of pathological thrombosis at sites of vessel occlusion. Of more modern interest, antibodies against PF4 may also arise in patients with COVID-19 (Coronavirus Disease 2019) or in patients who have been vaccinated against COVID-19, especially in recipients of adenovirus-based vaccines. For this latter group of patients, the terms VITT (vaccine-induced [immune] thrombotic thrombocytopenia) and TTS (thrombotic thrombocytopenia syndrome) have been coined. Another category associated with this pathophysiology comprises those in whom a precipitating event is not clear; this category is referred to as ‘spontaneous HIT-like syndrome’. Despite its name, it arises as an HIT-mimicking disorder but without antecedent heparin exposure. In this narrative review, we describe the development of antibodies against PF4, and associated pathophysiology, in such conditions.
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Pishko AM. Heparin-induced thrombocytopenia and cardiovascular surgery. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2021; 2021:536-544. [PMID: 34889428 PMCID: PMC8791147 DOI: 10.1182/hematology.2021000289] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Clinicians generally counsel patients with a history of heparin-induced thrombocytopenia (HIT) to avoid heparin products lifelong. Although there are now many alternative (nonheparin) anticoagulants available, heparin avoidance remains challenging for cardiac surgery. Heparin is often preferred in the cardiac surgery setting based on the vast experience with the agent, ease of monitoring, and reversibility. To "clear" a patient with a history of HIT for cardiac surgery, hematologists must first confirm the diagnosis of HIT, which can be challenging due to the ubiquity of heparin exposure and frequency of thrombocytopenia in patients in the cardiac intensive care unit. Next, the "phase of HIT" (acute HIT, subacute HIT A/B, or remote HIT) should be established based on platelet count, immunoassay for antibodies to platelet factor 4/heparin complexes, and a functional assay (eg, serotonin release assay). As long as the HIT functional assay remains positive (acute HIT or subacute HIT A), cardiac surgery should be delayed if possible. If surgery cannot be delayed, an alternative anticoagulant (preferably bivalirudin) may be used. Alternatively, heparin may be used with either preoperative/intraoperative plasma exchange or together with a potent antiplatelet agent. The optimal strategy among these options is not known, and the choice depends on institutional experience and availability of alternative anticoagulants. In the later phases of HIT (subacute HIT B or remote HIT), brief intraoperative exposure to heparin followed by an alternative anticoagulant as needed in the postoperative setting is recommended.
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Affiliation(s)
- Allyson M. Pishko
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Correspondence Allyson M. Pishko, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce St, 3rd Floor Dulles, Philadelphia, PA 19104; e-mail:
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Brown JA, Aranda-Michel E, Kilic A, Serna-Gallegos D, Bianco V, Thoma FW, Navid F, Sultan I. Outcomes With Heparin-Induced Thrombocytopenia After Cardiac Surgery. Ann Thorac Surg 2020; 112:487-493. [PMID: 33307073 DOI: 10.1016/j.athoracsur.2020.10.046] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 10/18/2020] [Accepted: 10/26/2020] [Indexed: 10/22/2022]
Abstract
BACKGROUND Heparin-induced thrombocytopenia (HIT) is an immune-mediated reaction to heparin that provokes a prothrombotic state and causes a decline in platelet count. Data describing outcomes of HIT after cardiac surgery are limited. This study sought to determine the impact of HIT on short-term outcomes after cardiac surgery. METHODS This was an observational study of cardiac surgeries from 2010 to 2018. Patients with HIT were matched against patients without HIT using 2:1 nearest-neighbor propensity matching. Matching was performed to assess the impact of HIT on operative mortality (The Society of Thoracic Surgeons definition) and thromboembolic events (including deep vein thrombosis, pulmonary embolism, stroke, and/or acute limb ischemia), which were the primary outcomes of interest. RESULTS Of 11,820 patients undergoing a Society of Thoracic Surgeons indexed cardiac surgery, 131 (1.1%) developed HIT after their index operation. After matching operative mortality was 21.8% in HIT patients compared with 5.3% in non-HIT patients. Thromboembolic events occurred in 29.1% of HIT patients compared with 2.9% in non-HIT patients. On subanalysis operative mortality was significantly higher for the HIT group without thromboembolic events (16.7%) and the HIT group with thromboembolic events (34.4%) compared with the non-HIT group (5.3%). However operative mortality was not significantly higher in the HIT group with thromboembolic events compared with the HIT group without thromboembolic events, after Bonferroni correction. CONCLUSIONS Although uncommon, HIT is a highly morbid and potentially lethal complication, which should reinforce the importance of timely recognition and treatment of this adverse outcome.
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Affiliation(s)
- James A Brown
- Division of Cardiac Surgery, Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Edgar Aranda-Michel
- Division of Cardiac Surgery, Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Arman Kilic
- Division of Cardiac Surgery, Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Derek Serna-Gallegos
- Division of Cardiac Surgery, Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Valentino Bianco
- Division of Cardiac Surgery, Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Floyd W Thoma
- Division of Cardiac Surgery, Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Forozan Navid
- Division of Cardiac Surgery, Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ibrahim Sultan
- Division of Cardiac Surgery, Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania; Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
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Avila L, Amiri N, Yenson P, Khan S, Zavareh ZT, Chan AKC, Williams S, Brandão LR. Heparin-Induced Thrombocytopenia in a Pediatric Population: Implications for Clinical Probability Scores and Testing. J Pediatr 2020; 226:167-172.e2. [PMID: 32640269 DOI: 10.1016/j.jpeds.2020.06.081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 06/23/2020] [Accepted: 06/25/2020] [Indexed: 01/19/2023]
Abstract
OBJECTIVES To determine the applicability of the 4Ts score and the Heparin-Induced Thrombocytopenia (HIT) Expert Probability (HEP) score in children with suspected HIT and to estimate the number of children potentially at risk of HIT. STUDY DESIGN We retrospectively estimated 4Ts and HEP scores in a cohort of 50 children referred for laboratory screening with enzyme immunoassay. In addition, minor modifications were introduced to the 4Ts score (modified 4Ts score) to adapt it for use in the pediatric setting. All patients with positive enzyme immunoassays were tested with serotonin release assay. We also extracted the number of patients started on heparins in a similar period of time. RESULTS The median age at the time of testing was 4 years (25th-75th percentile, 8.7 months to 13.5 years); 78% of patients had low and 22% had intermediate risk pretest probability scores using the original 4Ts score; 86% had low risk and 14% had intermediate risk scores using the modified 4Ts score; 54% of children had a HEP score of ≥2. Six patients (12%) had a positive (≥0.40 optical density units) enzyme immunoassay, but none had a positive serotonin release assay. Based on anticoagulation dose, there were 1-2 new daily potentially high-risk exposures to heparinoids at our institution. CONCLUSIONS The modified 4Ts and original 4Ts scores may be more adequate than the HEP score to determine HIT pretest probability in children. Despite the number of patients potentially at risk, HIT is rare in pediatrics.
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Affiliation(s)
- Laura Avila
- Division of Hematology/Oncology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada; Child Health Evaluative Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nour Amiri
- Division of Hematology/Oncology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Paul Yenson
- Division of Hematology/Oncology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Shirin Khan
- Division of Hematology/Oncology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada; G. Raymond Chang School of Continuing Education, Ryerson University, Toronto, Ontario, Canada
| | - Zahra Tofighi Zavareh
- Division of Hematology/Oncology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada; G. Raymond Chang School of Continuing Education, Ryerson University, Toronto, Ontario, Canada
| | - Anthony K C Chan
- Division of Hematology/Oncology, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Suzan Williams
- Division of Hematology/Oncology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Leonardo R Brandão
- Division of Hematology/Oncology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada.
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Kreuziger LB, Massicotte MP. Adult and pediatric mechanical circulation: a guide for the hematologist. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2018; 2018:507-515. [PMID: 30504351 PMCID: PMC6245997 DOI: 10.1182/asheducation-2018.1.507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Mechanical circulatory support (MCS) is the overarching term that encompasses the temporary and durable devices used in patients with severe heart failure. MCS disturbs the hematologic and coagulation system, leading to platelet activation, activation of the contact pathway of coagulation, and acquired von Willebrand syndrome. Ischemic stroke and major hemorrhage occur in up to 30% of patients. Hematologists are an essential part of the MCS team because they understand the delicate balance between bleeding and clotting and alteration of hemostasis with antithrombotic therapy. However, prior to this important collaborative role, learning the terminology used in the field and types of MCS devices allows improved communication with the MCS team and best patient care. Understanding which antithromobotic therapies are used at baseline is also required to provide recommendations if hemorrhage or thrombosis occurs. Additional challenging consultations in MCS patients include the influence of thrombophilia on the risk for thrombosis and management of heparin-induced thrombocytopenia. This narrative review will provide a foundation to understand MCS devices how to prevent, diagnose, and manage MCS thrombosis for the practicing hematologist.
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Affiliation(s)
- Lisa Baumann Kreuziger
- Division of Hematology, Department of Medicine, BloodCenter of Wisconsin, Medical College of Wisconsin, Milwaukee, WI; and
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East JM, Cserti-Gazdewich CM, Granton JT. Heparin-Induced Thrombocytopenia in the Critically Ill Patient. Chest 2017; 154:678-690. [PMID: 29253554 DOI: 10.1016/j.chest.2017.11.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 11/22/2017] [Accepted: 11/29/2017] [Indexed: 01/19/2023] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is associated with clinically significant morbidity and mortality. Patients who are critically ill are commonly thrombocytopenic and exposed to heparin. Although HIT should be considered, it is not usually the cause of thrombocytopenia in the medical-surgical ICU population. A systematic approach to the patient who is critically ill who has thrombocytopenia according to clinical features, complemented by appropriate laboratory confirmation, should lead to a reduction in inappropriate laboratory testing and reduce the use of more expensive and less reliable anticoagulants. If the patient is deemed as being at intermediate or high risk for HIT or if HIT is confirmed by means of the serotonin-release assay, heparin should be stopped, heparin-bonded catheters should be removed, and a direct antithrombin or fondaparinux should be initiated to reduce the risk of thrombosis. Warfarin is absolutely contraindicated in the acute phase of HIT; if administered, its effects must be reversed by using vitamin K.
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Affiliation(s)
- James M East
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
| | | | - John T Granton
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada.
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12
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Kang HG, Lee SJ, Chung JY, Cheong JS. Thrombocytopenia induced by dabigatran: two case reports. BMC Neurol 2017; 17:124. [PMID: 28662704 PMCID: PMC5492117 DOI: 10.1186/s12883-017-0900-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/21/2017] [Indexed: 11/17/2022] Open
Abstract
Background Vitamin K inhibitors (e.g. warfarin) and indirect thrombin inhibitors (e.g. heparin) are widely used to prevent thromboembolic disorders (e.g. myocardial infarction, venous thromboembolism, and stroke). These agents have been mainstays of anticoagulation for people older than 60 years. However, their administration is associated with a risk of bleeding and requires careful monitoring of patients. Novel oral anticoagulants (NOACs), such as dabigatran, are significantly safer in preventing thromboembolism than warfarin and heparin (sporadically causes thrombocytopenia) and are more specific for their target protein, thrombin. The major advantage of dabigatran, a direct thrombin inhibitor, is that it reversibly inhibits both free and clot-bound thrombin by tight binding affinity and the predictable pharmacodynamic effect. A few studies, however, reported that dabigatran can cause thrombocytopenia, although the underlying mechanism remains unclear. Thus, an antidote for dabigatran was developed to prevent thrombocytopenia. Case presentation In this report, we discuss two cases of thrombocytopenia and purpura after dabigatran treatment. A 73-year-old man showed hemorrhagic necrotic skin lesions on his neck and right hand. He was administered dabigatran (220 mg/day) for cerebral infarction for three days and his platelet count decreased abruptly (6000/μL). This suggested that dabigatran had caused thrombocytopenia and purpura; therefore, dabigatran administration was discontinued. The results of a blood test, performed 14 days after stopping dabigatran treatment, showed that the platelet count had recovered to the normal range of more than 150,000/μL. A 75-year-old woman had taken warfarin continuously for 8 years. However, she had a new cerebral infarction. Therefore, warfarin treatment was replaced with dabigatran (300 mg/day). Her platelet count decreased (41,000/μL) significantly and dabigatran treatment was discontinued. The blood test results show that platelet counts gradually recovered to the normal range. Conclusions Dabigatran application may cause bleeding; therefore, careful monitoring during dabigatran treatment is required to prevent thrombocytopenia. An explanation is that the interaction of dabigatran with thrombin, because of its strong binding affinity, may cause the observed thrombocytopenia.
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Affiliation(s)
- Hyun Goo Kang
- Department of Neurology, Chosun University School of Medicine, Gwangju, 61453, Republic of Korea
| | - Seung Jae Lee
- Research Center for Bioactive Materials and Department of Chemistry, Chonbuk National University, Jeonju, 54896, Republic of Korea
| | - Ji Yeon Chung
- Department of Neurology, Chosun University School of Medicine, Gwangju, 61453, Republic of Korea
| | - Jin Sung Cheong
- Department of Neurology, Wonkwang University School of Medicine and Hospital, Iksan, 54538, Jeonbuk, Republic of Korea.
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Pishko AM, Cuker A. Heparin-Induced Thrombocytopenia in Cardiac Surgery Patients. Semin Thromb Hemost 2017; 43:691-698. [PMID: 28597462 DOI: 10.1055/s-0037-1602664] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Allyson M Pishko
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Adam Cuker
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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