New method to differentiate between lupus anticoagulants, progressive coagulation inhibitors and coagulation factor deficiencies in the mixing tests

INTRODUCTION

Mixing tests in activated partial thromboplastin time (APTT) are used for the differentiation between lupus anticoagulants (LA), coagulation inhibitors, and factor deficient samples with APTT prolongation. However, the indexes for the differentiation have not been established. The present study aimed to develop new mixing test indexes for the differentiation.

METHODS

Twenty-six LA-positive, 8 progressive coagulation factor VIII inhibitor, and 35 coagulation deficient samples were employed. APTT were measured for normal plasma, patient plasma, and mixing plasma prepared at a ratio of 1:1 proportion in both without incubation and 2 h-incubation. New two parameters named as ALD50 and mixture plasma-patient plasma after Warming change rate Subtraction (WaS) calculated from the clotting times of normal, 1:1 mixing and patient samples with/without 2 h-incubation were established. In the samples with WaS result of <10.2%, ALD50 of ≥87.8%, and < 87.8% were defined as LA and coagulation factor deficiency, respectively, and WaS of ≥10.2% defined progressive coagulation factor inhibitors.

RESULTS

Sensitivity and specificity to LA were 80.8% and 93.0% for ALD50, and sensitivity and specificity to progressive coagulation factor inhibitor were 100.0% and 100.0% for WaS, respectively. The agreement between sample classification and WaS-ALD50 was 88.4% (61/69).

CONCLUSIONS

ALD50 and WaS showed acceptable sensitivity and specificity to LA and progressive coagulation factor inhibitor, respectively. These indexes would be useful for the differentiation between LA, factor deficiency, and progressive coagulation factor inhibitor in the mixing tests.

Isolated Prothrombin Deficiency: A Case Report of a Rare Coagulation Disorder and Review of Literature

Congenital prothrombin deficiency is a rare hemorrhagic disorder, frequent in areas with high degrees of consanguinity as it is autosomal recessive in nature. Clinical manifestations are highly variable, ranging from mild episodes of bleeding to severe hemorrhages. Here, we report a child with isolated prothrombin deficiency who presented with a history of pain and soreness in the prepuce associated with bleeding. Laboratory evaluation showed an altered coagulation profile with a prothrombin activity level of 29.8%, indicative of factor-II deficiency. This case highlights the importance of coagulation screening in all patients before even minor invasive procedures and the role of a detailed coagulation profile in confirming a diagnosis in the case of abnormal screening tests.

Comparison of different algorithms for lupus anticoagulant detection: a single-center experience

Background

The laboratory tests for lupus anticoagulant (LA) detection comprise complex and multistep coagulation testing procedures. There is no established gold standard assay or direct comparison of algorithms as recommended by different guidelines.

Objectives

This study aimed to evaluate and compare the LA detection performance of different laboratory algorithms suggested by the existing guidelines.

Methods

The routine LA test data of 1801 plasma samples, including 188 LA-positive and 1613 LA-negative samples, were re-evaluated by applying the algorithms recommended by existing guidelines and were interpreted using various methods. Diagnostic performance indices for each LA detection algorithm were compared with those of the other algorithms. The efficacies of the different interpretation methods were analyzed to determine a suitable interpretation methodology for each assay.

Results

The diagnostic performance for detecting LA varied by the algorithm and method of interpretation used. All laboratory algorithms displayed exceptional diagnostic performance with all diagnostic parameters of >90.0%. Nearly perfect agreement was observed in all algorithms when compared to the Clinical and Laboratory Standards Institute 2014 guideline interpreted by normalized screen-to-confirm ratio (NSCR) and mixing test-specific cutoff (MTC), as a reference assay (Cohen's kappa coefficient, >0.90 [range, 0.94-1.00]). A combination of the index of circulating anticoagulant and NSCR was optimal for interpreting the activated partial thromboplastin time-based test, whereas a combination of the MTC and NSCR was suitable for the diluted Russell's viper venom time-based test.

Conclusion

All laboratory algorithms showed equivalent diagnostic performance. Establishing the best method of interpretation for each assay is recommended to improve LA detection performance.

Comparison of the Correlation Between Coagulation Indices and Rivaroxaban Concentrations

BACKGROUND

Rivaroxaban has predictable pharmacokinetics and pharmacodynamics. However, monitoring rivaroxaban concentrations should be provided for special patients with hepatic insufficiency, high bleeding risk, and high thrombotic risk.

OBJECTIVE

This study aimed to correlate chromogenic anti-Xa assay, prothrombin time (PT), activated partial thromboplastin time (APTT), thromboelastogram reaction time (TEG R-time), and rivaroxaban concentration measured by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) (MS-Riva).

METHODS

Peripheral venous blood was collected from recruited patients 30 minutes before and 2 to 4 hours after drug administration. High-performance liquid chromatography-tandem mass spectrometry and chromogenic anti-Xa assay measured rivaroxaban concentration. Different assays were compared by Pearson correlation coefficient and Bland-Altman analysis.

RESULTS

A total of 104 patients with 191 plasma were included in the study. Overall analysis shows that chromogenic anti-Xa assay, PT, APTT, and TEG R-time strongly correlated with MS-Riva (r = 0.986; r = 0.884; r = 0.741; r = 0.739; P < 0.001). Rivaroxaban peak concentration detected by HPLC-MS/MS (MS-peak) showed a very strong correlation with the chromogenic anti-Xa assay (r = 0.977, P < 0.001) and moderate correlation with PT, APTT, and TEG R-time (r = 0.670; r = 0.571; r = 0.481, P < 0.001). Rivaroxaban trough concentration detected by HPLC-MS/MS (MS-trough) correlated strongly with the chromogenic anti-Xa assay (r = 0.884, P < 0.001), weakly with APTT (r = 0.313; P = 0.043), and not significantly with PT and TEG R-time (P = 0.140; P = 0.341).

CONCLUSION AND RELEVANCE

High-performance liquid chromatography-tandem mass spectrometry/MS is the preferred choice for monitoring peak and tough concentrations, followed by anti-Xa, while PT is only suitable for peak concentrations. This study can help the clinicians to better adjust the medication regimen and reduce the risk of recurrence of thrombosis as well as the risk of bleeding.

Clinical outcomes and predictors of bleomycin polidocanol foam sclerotherapy treatment response in venous malformations

OBJECTIVE

To evaluate the safety and efficacy of bleomycin polidocanol foam (BPF) sclerotherapy for venous malformations (VMs) and analyze the associated clinical outcomes and predictors.

METHODS

We retrospectively assessed BPF sclerotherapy outcomes in 138 patients with VMs. We analyzed pain levels, lesion volume reduction, and subjective perception of response. Logistic regression analysis was performed to identify potential predictors of treatment outcome. Additionally, we carefully monitored and recorded complications.

RESULTS

There was a notable average reduction in lesion volume by 78.50% ± 15.71%. The pain numerical rating scale (NRS) score decreased from 4.17 ± 2.63 prior to treatment to 1.05 ± 1.54 afterward, and 70.3% of the patients experienced effective relief after a single BPF treatment. Multivariate analysis revealed that a high baseline NRS (odds ratio [OR]:  4.026) and elevated activated partial thromboplastin time (APTT, OR: 1.200) were positive predictors of pain reduction. Additionally, a high baseline NRS score (OR: 1.992) and elevated thrombocytocrit (PCT, OR: 2.543) were positive predictors of incomplete postoperative pain relief. Minor complications occurred in 31 (22.46%) patients.

CONCLUSION

BPF sclerotherapy is safe and effective for VMs, resulting in significant reduction in lesion volume, improved symptoms, and minimal complications. APTT and PCT levels are important predictors of pain outcomes following BPF treatment.

Triple-positive antiphospholipid syndrome does not guarantee positivity in each lupus anticoagulant assay

BACKGROUND

Triple positivity for all 3 criteria antiphospholipid antibodies confers high risk of symptom development in carriers, and recurrence in antiphospholipid syndrome (APS). Most triple-positivity studies report lupus anticoagulant (LA) testing as positive without distinguishing between positivity with dilute Russell's viper venom time (dRVVT) and activated partial thromboplastin time (APTT) and single-assay positivity or only perform dRVVT. Single LA assay repertoires remain in use in some centers, which risks missing some triple positives. Positivity with both assays may identify higher risk.

OBJECTIVES

The aim of this study is to investigate the frequency of single LA assay positivity in triple-positive patients.

METHODS

Three hundred forty-two triple-positive profiles from nonanticoagulated patients (237 APS, 45 systemic lupus erythematosus without APS symptoms, and 60 nonclinical criteria) were identified from laboratory databases and assessed for LA positivity by dRVVT and/or APTT.

RESULTS

Seventy-three of 237 (30.8%) APS samples were LA-positive with 1 assay, 40/237 (16.9%) by dRVVT only, and 33/237 (13.9%) with APTT only. Nineteen of 45 (42.2%) were LA-positive with 1 assay in the systemic lupus erythematosus cohort; 12/45 (26.7%) with dRVVT only and 7/45 (15.5%) with APTT only. Thirty-three of 60 (55.0%) were LA-positive with 1 assay in the nonclinical criteria cohort; 24/60 (40.0%) with dRVVT only and 9/60 (15.0%) with APTT only. The most common solid-phase assay profile was elevated immunoglobulin G aCL and aβ2GPI.

CONCLUSION

Up to 55.0% of triple-positive samples were positive in 1 LA assay, representing significant potential for misdiagnosis and inappropriate management via single LA assay repertoires.

Blood Coagulation Activities of Cotton-Alginate-Copper Composites

Alginate-based materials have gained significant attention in the medical industry due to their biochemical properties. In this article, we aimed to synthesize Cotton-Alginate-Copper Composite Materials (COT-Alg(-)Cu(2+)). The main purpose of this study was to assess the biochemical properties of new composites in the area of blood plasma coagulation processes, including activated partial thromboplastin time (aPTT), prothrombin time (PT), and thrombin time (TT). This study also involved in vitro antimicrobial activity evaluation of materials against representative colonies of Gram-positive and Gram-negative bacteria and antifungal susceptibility tests. The materials were prepared by immersing cotton fibers in an aqueous solution of sodium alginate, followed by ionic cross-linking of alginate chains within the fibers with Cu(II) ions to yield antimicrobial activity. The results showed that the obtained cotton-alginate-copper composites were promising materials to be used in biomedical applications, e.g., wound dressing.

Anti-Factor-Xa and Activated Partial Thromboplastin Time Concordance and Outcomes in Adults Undergoing Extracorporeal Membrane Oxygenation: A Secondary Analysis of the Pilot Low-Dose Heparin in Critically Ill Patients Undergoing Extracorporeal Membrane Oxygenation Randomized Trial

OBJECTIVES

To determine the concordance between activated partial thromboplastin time (aPTT) and anti-factor-Xa (anti-Xa) in adults undergoing extracorporeal membrane oxygenation (ECMO) and to identify the factors associated with discordant paired aPTT/anti-Xa.

DESIGN

Pre-planned secondary analysis of the Low-Dose Heparin in Critically Ill Patients Undergoing Extracorporeal Membrane Oxygenation pilot randomized unblinded, parallel-group controlled trial.

SETTING

Two ICUs in two university hospitals.

PATIENTS

Thirty-two critically ill patients who underwent ECMO and who had at least one paired aPTT and anti-Xa assay performed at the same time.

INTERVENTIONS

We analyzed the concordance between aPTT and anti-Xa and identified factors associated with discordant paired aPTT/anti-Xa based on their respective therapeutic ranges. We also compared biological parameters between heparin resistance episode and no heparin resistance.

MEASUREMENTS AND MAIN RESULTS

Of the 32 patients who were included in this study, 24 (75%) had at least one discordant paired aPTT/anti-Xa. Of the 581 paired aPTT/anti-Xa that were analyzed, 202 were discordant. The aPTT was relatively lower than anti-Xa in 66 cases (32.7%) or relatively higher than anti-Xa in 136 cases (67.3%). Thirty-three heparin resistance episodes were identified in six patients (19%).

CONCLUSIONS

In these critically ill patients undergoing ECMO, one third of paired aPTT/anti-Xa measures was discordant. Coagulopathy and heparin resistance might be the reasons for discordance. Our results support the potential importance of routinely monitoring both tests in this setting.

A Case of Congenital Mild Hemophilia Diagnosed After Wisdom Teeth Extraction

Hemophilia A is a recessive congenital deficiency of factor VIII that is characterized by normal bleeding time, normal prothrombin time, and prolonged activated partial thromboplastin time. In moderate and severe cases, abnormal bleeding is observed even after minor trauma, and the diagnosis is usually made by the age of 5-6 years, whereas in mild cases, abnormal bleeding is detected after major trauma or surgery. Herein, we present a case of hemophilia A that was discovered due to difficulties with hemostasis after tooth extraction.

Effect of emicizumab-neutralizing antibodies on activated partial thromboplastin time-based clotting time test results in patients treated with emicizumab

Background

Emicizumab is a bispecific humanized monoclonal antibody that shortens the activated partial thromboplastin time (aPTT), making aPTT-based tests unreliable.

Objectives

To evaluate the efficacy of a mixture of 2 anti-idiotype monoclonal antibodies (anti-emi) in neutralizing emicizumab in samples from persons with hemophilia A treated with emicizumab.

Methods

Fifty samples from persons with hemophilia A treated with emicizumab were analyzed for aPTT and factor VIII procoagulant activity; FVIII inhibitor titer was measured using Nijmegen-Bethesda assay in 50 plasma samples of additional patients (positive for FVIII inhibitor) treated with emicizumab. FVIII procoagulant activity and inhibitor titer were measured using 1-stage (Actin FS, Siemens) and chromogenic assays with bovine regents (Factor VIII Chromogenic Assay, Siemens). Emicizumab concentration was measured by modified a 1-stage assay calibrated with a drug-specific calibrator (r2 Diagnostics Inc). All the tests were performed on Sysmex CS-2400 (Sysmex) before and after the addition of anti-emi (Chugai Pharmaceutical).

Results

Emicizumab concentrations measured after neutralization were <1.6 μg/mL in all samples. FVIII levels were >480 IU/dL with an aPTT of <30.8 seconds in all samples before neutralization and were <1 IU/dL with an aPTT of >70 seconds after adding anti-emi. FVIII inhibitor resulted in a false negative result in 44 of 50 samples measured with the 1-stage assay before neutralization. A good correlation (r = 0.98) was found between inhibitor titer measured using the chromogenic (insensitive to emicizumab) and 1-stage assays after neutralization.

Conclusion

The anti-emi antibodies were shown to completely neutralize emicizumab, making samples pretreated with anti-emi analyzable with the 1-stage assay.

Difficulties in laboratory diagnosis of coexistent lupus anticoagulant and factor VIII inhibitors: case report and review of literature

BACKGROUND

Whereas lupus anticoagulant (LA) and anti-factor VIII (anti-VIII) antibody are both acquired autoimmune coagulation inhibitors, they exhibit different pathophysiologic mechanisms and opposite clinical manifestations. Distinguishing between these two inhibitors is therefore essential for optimizing appropriate management. Harboring both antibodies, which is a rare condition, is of a challenging and confounding laboratory work-up.

CASE PRESENTATION

We illustrate a case report of a 39-year-old man admitted for the management of recurrent deep-vein thrombosis. Curiously, the initial physical examination revealed several hematoma and bruises of varying sizes. Biologically, a prolonged activated partial thromboplastin time (APTT) was objectified and was not corrected by the mixing study. The following detection of synchronous LA and anti-VIII was made using specific assays.

CONCLUSIONS

Through this case, we illustrate the complexity of diagnosing coexistent LA and FVIII inhibitors. In fact, the biological hallmark of both inhibitors is an isolated prolonged APTT that does not correct by the mixing study. Despite the progress in LA and anti-VIII assays and the ongoing updating of standardized recommendations, the lack of specific tests for LA and the limited availability of VIII quantification tests other than the clot-based assays make it difficult to distinguish adequately between the two inhibitors. Therefore, it is crucial to correlate test results with clinical features and patient evaluation.

Lupus Anticoagulant Detection under the Magnifying Glass

Diagnosis of antiphospholipid syndrome (APS) requires the presence of a clinical criterion (thrombosis and/or pregnancy morbidity), combined with persistently circulating antiphospholipid antibodies (aPL). Lupus anticoagulant (LA) is one of the three laboratory parameters (the others being antibodies to either cardiolipin or β2-glycoprotein I) that defines this rare but potentially devastating condition. For the search for aCL and aβ2-GP-I, traditionally measured with immunological solid-phase assays (ELISA), several different assays and detection techniques are currently available, thus making these tests relatively reliable and widespread. On the other hand, LA detection is based on functional coagulation procedures that are characterized by poor standardization, difficulties in interpreting the results, and interference by several drugs commonly used in the clinical settings in which LA search is appropriate. This article aims to review the current state of the art and the challenges that clinicians and laboratories incur in the detection of LA.

Reagent Effects on the Activated Partial Thromboplastin Time Clot Waveform Analysis: A Multi-Centre Study

(1) Background: The activated partial thromboplastin time (APTT)- based clot waveform analysis (CWA) quantitatively extends information obtained from the APTT waveform through its derivatives. However, pre-analytical variables including reagent effects on the CWA parameters are poorly understood and must be standardized as a potential diagnostic assay. (2) Methods: CWA was first analysed with patient samples to understand reagent lot variation in three common APTT reagents: Pathromtin SL, Actin FS, and Actin FSL. A total of 1055 healthy volunteers were also recruited from seven institutions across the Asia-Pacific region and CWA data were collected with the Sysmex CS analysers. (3) Results: CWA parameters varied less than 10% between lots and the linear mixed model analysis showed few site-specific effects within the same reagent group. However, the CWA parameters were significantly different amongst all reagent groups and thus reagent-specific 95% reference intervals could be calculated using the nonparametric method. Post-hoc analysis showed some degree of influence by age and gender with weak correlation to the CWA (r < 0.3). (4) Conclusions: Reagent type significantly affects APTT-based CWA with minimal inter-laboratory variations with the same coagulometer series that allow for data pooling across laboratories with more evidence required for age- and gender-partitioning.

Concordance Between Active Partial Thromboplastin Time and Anti-Factor Xa Assays in Neurocritically Ill Patients Receiving Subcutaneous Heparin Prophylaxis

Background

Laboratory monitoring is not recommended when subcutaneous unfractionated heparin (SQ-UFH) is administered at prophylactic doses. However, aPTT prolongation and associated hemorrhage has been reported in the neurocritically ill. At our institution, Neuroscience Intensive Care Unit (Neuro-ICU) patients with prolonged aPTT are further evaluated with a follow up aPTT and anti-factor Xa.

Purpose

The purpose of this study was to describe concordance between aPTT and anti-factor Xa in neurocritically ill patients receiving prophylactic SQ-UFH with evidence of aPTT prolongation.

Methods

A retrospective chart review of adult patients admitted to the Neuro-ICU from June 2017 to June 2019 was performed. Patients were included if they received SQ-UFH with aPTT levels and at least one anti-factor Xa level drawn within one hour of each other. Concordance between paired aPTT and anti-factor Xa was evaluated using Cohen's weighted kappa.

Results

Forty two patients with 56 paired aPTT and anti-factor Xa levels were included. The most prescribed SQ-UFH regimen was 5000 units every 8 hours (60.7%) and anti-factor Xa levels were drawn a median (IQR) of 5.7 (3.1-10.7) hours after the SQ-UFH dose. Only 16 (28.6%) pairs were in concordance. The analysis showed a weighted kappa of .09; 95% CI [-.05 to .22] indicating poor agreement.

Conclusions

In neurocritically ill patients receiving prophylactic SQ-UFH with aPTT prolongation, there was poor concordance between aPTT and anti-factor Xa. This suggests that aPTT prolongation may not be solely driven by heparin activity and further evaluation of mechanistic drivers for coagulopathy in this population is necessary.

SERPINE1 mRNA Binding Protein 1 Is Associated with Ischemic Stroke Risk: A Comprehensive Molecular-Genetic and Bioinformatics Analysis of SERBP1 SNPs

The SERBP1 gene is a well-known regulator of SERPINE1 mRNA stability and progesterone signaling. However, the chaperone-like properties of SERBP1 have recently been discovered. The present pilot study investigated whether SERBP1 SNPs are associated with the risk and clinical manifestations of ischemic stroke (IS). DNA samples from 2060 unrelated Russian subjects (869 IS patients and 1191 healthy controls) were genotyped for 5 common SNPs-rs4655707, rs1058074, rs12561767, rs12566098, and rs6702742 SERBP1-using probe-based PCR. The association of SNP rs12566098 with an increased risk of IS (risk allele C; p = 0.001) was observed regardless of gender or physical activity level and was modified by smoking, fruit and vegetable intake, and body mass index. SNP rs1058074 (risk allele C) was associated with an increased risk of IS exclusively in women (p = 0.02), non-smokers (p = 0.003), patients with low physical activity (p = 0.04), patients with low fruit and vegetable consumption (p = 0.04), and BMI ≥25 (p = 0.007). SNPs rs1058074 (p = 0.04), rs12561767 (p = 0.01), rs12566098 (p = 0.02), rs6702742 (p = 0.036), and rs4655707 (p = 0.04) were associated with shortening of activated partial thromboplastin time. Thus, SERBP1 SNPs represent novel genetic markers of IS. Further studies are required to confirm the relationship between SERBP1 polymorphism and IS risk.

Association of aPTT-Guided Anticoagulation Monitoring with Thromboembolic Events in Patients Receiving V-A ECMO Support: A Systematic Review and Meta-Analysis

BACKGROUND

The initiation of extracorporeal membrane oxygenation (ECMO) is associated with complex inflammatory and coagulatory processes, raising the need for systemic anticoagulation. The balance of anticoagulatory and procoagulant factors is essential, as therapeutic anticoagulation confers a further risk of potentially life-threatening bleeding. Therefore, our study aims to systematize and analyze the most recent evidence regarding anticoagulation monitoring and the thromboembolic events in patients receiving veno-arterial ECMO support.

METHODS

Using the PRISMA guidelines, we systematically searched the Scopus and PubMed databases up to October 2022. A weighted effects model was employed for the meta-analytic portion of the study.

RESULTS

Six studies comprising 1728 patients were included in the final analysis. Unfractionated heparin was used for anticoagulation, with an activated partial thromboplastin time (aPTT) monitoring goal set between 45 and 80 s. The majority of studies aimed to investigate the incidence of adverse events and potential risk factors for thromboembolic and bleeding events. None of the authors found any association of aPTT levels with the occurrence of thromboembolic events. Finally, the most frequent adverse events were hemorrhage (pooled 43%, 95% CI 28.4; 59.5) and any kind of thrombosis (pooled 36%, 95% CI 21.7; 53.7), and more than one-half of patients did not survive to discharge (pooled 54%).

CONCLUSIONS

Despite the tremendous development of critical care, aPTT-guided systemic anticoagulation is still the standard monitoring tool. We did not find any association of aPTT levels with thrombosis. Further evidence and new trials should clarify the true incidence of thromboembolic events, along with the best anticoagulation and monitoring strategy in veno-arterial ECMO patients.

Novel Monitoring and Dose Adjustment of Argatroban, a Direct Thrombin Inhibitor, to Maintain Therapeutic Anticoagulation in a Patient With Antiphospholipid Antibody Syndrome, Heparin-Induced Thrombocytopenia, and COVID-19 Pneumonia

In patients who require systemic anticoagulation, a reliable monitoring method is required to ensure anticoagulation is maintained within the correct therapeutic window and patients are treated appropriately. When titrating direct thrombin inhibitors (DTIs), dilute thrombin time (dTT) measurements have been demonstrated to be more reliable and accurate than activated partial thromboplastin time (aPTT) measurements and thus often the preferred DTI assessment. However, a clinical need arises when both dTT measurements are not readily available and aPTT measurements are unreliable.

CASE SUMMARY

A 57-year-old woman with a history of antiphospholipid antibody syndrome, heparin-induced thrombocytopenia, and multiple prior deep venous thromboses and pulmonary emboli was admitted with COVID-19 pneumonia and intubated due to hypoxic respiratory failure. Argatroban was initiated in place of her home medication warfarin. However, the patient had a prolonged aPTT value at baseline and overnight dTT assay measurements were limited at our institution. A multidisciplinary team of hematology and pharmacy clinicians created a modified patient-specific aPTT target range and argatroban dosing was titrated accordingly. Subsequent aPTT values in the modified target range corresponded to therapeutic dTT values, indicating therapeutic anticoagulation was successfully achieved and maintained. Patient blood samples were additionally evaluated retrospectively using an investigational novel point-of-care test that detected and quantified the argatroban anticoagulant effect.

CONCLUSIONS

Therapeutic anticoagulation with a DTI in a patient with unreliable aPTT measurements can be achieved with use of a modified patient-specific aPTT target range. Early validation of an investigational rapid testing alternative for DTI monitoring is promising.

The activated partial thromboplastin time-clot waveform analysis in hemophilia: Does it help in differentiation?

INTRODUCTION

The clot waveform analysis (CWA) provide valuable information beyond clotting time. The present study was planned to assess whether the activated partial thromboplastin time (aPTT)-CWA can differentiate between hemophilia A (HA), hemophilia B (HB), or hemophilia A with inhibitors (HAWI).

METHODS

The aPTT-CWA was generated by an optical detection system (ACL-TOP™ 500 coagulation analyzer) and the other tests were performed as per instructions from the manufacturer in the kit.

RESULTS

A total of 75 samples (47-HA, 16-HAWI, and 12-HB) with prolonged aPTT were recruited. On analyzing the quantitative aPTT-CWA data of HA (non-inhibitors) and HB samples, the width of acceleration 1 [+] peak was the differentiating finding. Among the significant parameters, the second derivative [+] peak was lower in both mild and moderate HA, equating to HB. The time for the height of 1/2 fibrin formation and width of velocity was significantly higher in mild, moderate and severe HA. The study did not show any significant differentiating finding while comparing HAWI and hemophilia A non-inhibitors (HANI). In the subgroups of HAWI and HANI with aPTT <70 s and 70-100 s, the second derivative [+] peak (2A) was higher and the time for the height of 1/2 fibrin formation (1C) was lesser in HAWI.

CONCLUSION

The aPTT-CWA parameters may be supportive for the differentiation of hemophilia including its severity and the existence of inhibitors.

Repeated bleeding caused by acquired hemophilia A after endoscopic submucosal dissection: A case report and literature review

Endoscopic submucosal dissection (ESD) has been widely used in the treatment of gastrointestinal tract lesions, and hemorrhage is one of the most common complications. The aim of the present study was to investigate the clinical characteristics of hemorrhage after ESD in patients with acquired hemophilia A (AHA). Firstly, a case of AHA with multiple bleeding events after ESD is reported. Colonoscopy was used to perform ESD treatment of the submucosal tumor, and immunohistochemical analysis was used to analyze the tumor properties. Secondly, literature relevant to postoperative hemorrhage caused by AHA was researched and analyzed, with the changes in activated partial thromboplastin time (APTT) before and after operation, coagulation factor VIII (FVIII) activity, FVIII inhibitor value and treatment plan noted. The majority of patients with AHA had no history of coagulation disorder or genetic disease and showed a normal APTT. However, it was found that the APTT value gradually increased after bleeding. In addition, the APTT correction test did not correct for prolonged APTT and FVIII antibody positivity in AHA. There was no bleeding or bleeding tendency prior to surgery in patients with AHA. The study concludes that when repeated bleeding and a poor hemostatic effect occurs, it is necessary to be alerted to the possibility of AHA, as an early diagnosis is essential for effective hemostasis.

Evaluation of a Multimodal Heparin Laboratory Monitoring Protocol in Adult Extracorporeal Membrane Oxygenation Patients

BACKGROUND

Anticoagulation monitoring practices vary during extracorporeal membrane oxygenation (ECMO). The Extracorporeal Life Support Organization describes that a multimodal approach is needed to overcome assay limitations and minimize complications.

OBJECTIVE

Compare activated clotting time (ACT) versus multimodal approach (activated partial thromboplastin time (aPTT)/anti-factor Xa) for unfractionated heparin (UFH) monitoring in adult ECMO patients.

METHODS

We conducted a single-center retrospective pre- (ACT) versus post-implementation (multimodal approach) study. The incidence of major bleeding and thrombosis, blood product and antithrombin III (ATIII) administration, and UFH infusion rates were compared.

RESULTS

Incidence of major bleeding (69.2% versus 62.2%, p = 0.345) and thrombosis (23% versus 14.9%, p = 0.369) was similar between groups. Median number of ATIII doses was reduced in the multimodal group (1.0 [IQR 0.0-2.0] versus 0.0 [0.0 -1.0], p = 0.007). The median UFH infusion rate was higher in the ACT group, but not significant (16.9 [IQR 9.6-22.4] versus 13 [IQR 9.6-15.4] units/kg/hr, p = 0.063). Fewer UFH infusion rate changes occurred prior to steady state in the multimodal group (0.9 [IQR 0.3 -1.7] versus 0.1 [IQR 0.0-0.2], p < 0.001).

CONCLUSION

The incidence of major bleeding and thrombosis was similar between groups. Our multimodal monitoring protocol standardized UFH infusion administration and reduced ATIII administration.

Performance characteristics of 5 numerical indexes in mixing test interpretation under coexistence of lupus anticoagulant and coagulation factor deficiency

Background

The mixing test is useful to investigate the cause of unexpectedly prolonged activated partial thromboplastin time (APTT). Several indexes are available for distinguishing correction from non-correction (ie, factor deficiency from inhibitors), but their performance characteristics may differ because of their different formulas. Furthermore, it is unclear how each index performs under the coexistence of factor deficiency and inhibitors.

Objectives

The objective of this study was to examine the differences in indexes, depending on factor VIII activity (FVIII:C) levels and lupus anticoagulant (LA) titers in test samples.

Methods

APTT was measured in spiked samples with various FVIII:C levels and LA titers, normal pooled plasma (NPP), and their 4:1, 1:1, and 1:4 mixtures. The following 5 indexes were calculated: index of circulating anticoagulant, mixing test normalized ratio, 4:1 and 1:1 percent corrections, and an APTT difference between the 1:1 mixture and NPP. The samples with LA, showing correction, were measured for FVIII:C in a one-stage assay to check parallelism.

Results

All indexes showed correction under FVIII deficiency and non-correction under higher LA titers. However, under lower LA titers, some indexes showed non-correction but others showed correction because of dilution effects and variations in formulas and/or sample mix ratios. The differences among the indexes were more pronounced under coexistent FVIII deficiency and LA, even though LA titers were equal in the tested samples; samples with lower FVIII:C showed correction, whereas those with normal FVIII:C showed non-correction. The samples tested for FVIII:C showed non-parallelism.

Conclusion

Each index had different performance characteristics to LA samples, which were pronounced under low FVIII:C levels in test samples.

Activated Partial Thromboplastin Time or Prothrombin Time Prolongation During Rivaroxaban Administration: Clinical Risk Factors and Outcomes Analysis

Activated partial thromboplastin time (aPTT) or prothrombin time (PT) is often detected after rivaroxaban administration, and it is known that aPTT or PT can be prolonged or normal. However, the clinical risk factors and outcomes of prolongation were unknown. In a single-center, retrospective case-control study, adult inpatients who had aPTT/PT tested before and after administration of rivaroxaban during a designated 12-month period were eligible for inclusion. Depending on whether their aPTT/PT was prolonged, patients were allocated to the prolonged case or normal control group. Demographics, rivaroxaban indications and daily dose, and laboratory values were compared. Multivariate logistic regression was used to identify independent risk factors. The changes in laboratory values and clinical outcomes were analyzed. A total of 155 patients were included in the study among which 54 (34.84%) were reported to have either or both aPTT/PT prolonged. The average prolongation time of PT was between 0.8 and 0.9 s, and 1.8 and 3.5 s for aPTT. Multivariable regression modeling showed that height (odds ratio [OR] 1.12, 95% confidence interval [CI] 1.02-1.22, P = .02) and human albumin replacement (OR 3.19, 95% CI 1.05-9.74, P = .04) were independent risk factors for aPTT/PT prolongation. The incidence of bleeding events and changes in laboratory values were similar between the groups. Patient height and receiving human albumin replacement were independent risk factors for aPTT/PT mild prolongation caused by rivaroxaban. The prolongation was not associated with an increased occurrence of bleeding events.

Predictive value of coagulation function and D-dimer for pregnancy outcome in pregnancy-induced hypertension

OBJECTIVE

To observe the predictive values of plasma prothrombin time (PT), fibrinogen (FIB), activated partial thromboplastin time (APTT) and D-dimer (DD) levels for pregnancy outcome in parturients with hypertensive disorder complicating pregnancy (HDCP).

METHODS

A retrospective analysis was conducted on 107 parturients with gestational hypertension admitted to Xi'an International Medical Center Hospital from April 2018 to April 2021 (research group) and on 50 healthy parturients who underwent physical examination in the same period (control group). PT, FIB, APTT, and DD values of all parturients included in the study were examined at admission, and pregnancy outcomes were recorded. The working curve (ROC) of the relationship between coagulation function test indicators and pregnancy outcomes of parturients in the research group was analyzed.

RESULTS

Compared to the control group, PT and APTT values of parturients in the research group were lower, while FIB and DD levels were markedly higher (P < 0.05). Correlation analysis showed APTT and PT were negatively correlated with the severity of disease (both P < 0.001), while the expression of FIB and DD were positively correlated with it (both P < 0.001). Parturients were divided into an adverse outcome group and a normal outcome group. Logistic regression analysis showed that pre-pregnancy body mass index, PT, APTT, FIB, DD and other indicators were all risk factors for adverse outcome in HDCP parturients. ROC curve analysis showed that the area under the curve of these combined risk factors for predicting adverse outcome was 0.971.

CONCLUSION

Levels of PT, FIB, APTT, and DD are abnormal in parturients with different degrees of HDCP. Regular coagulation function tests can effectively detect HDCP, enabling improvement of pregnancy outcome.

Coagulation Factors and Natural Anticoagulants as Surrogate Markers of Preeclampsia and Its Subtypes: A Case-Control Study in a Ghanaian Population

Preeclampsia (PE) is associated with endothelial injury and hemostatic abnormalities. However, the diagnostic role of coagulation parameters and natural anticoagulants in predicting PE has not been explored in Ghana. This study assessed plasma levels of these factors as surrogate markers of PE and its subtypes. This case-control study included 90 women with PE (cases) and 90 normotensive pregnant women (controls). Blood samples were drawn for the estimation of complete blood count and coagulation tests. The prothrombin time (PT), activated partial thromboplastin time (APTT), and the calculation of the international normalized ratio (INR) were determined by an ACL elite coagulometer while the levels of protein C (PC), protein S (PS), antithrombin III (ATIII), and D-dimers were also measured using the solid-phase sandwich enzyme-linked immunosorbent assay (ELISA) method. All statistical analyses were performed using the R Language for Statistical Computing. Results showed significantly (p < .05) shortened APTT (28.25 s) and higher D-dimer levels (1219.00 ng/mL) among PE women, as well as low levels of PC (1.02 µg/mL), PS (6.58 µg/mL), and ATIII (3.99 ng/mL). No significant difference was found in terms of PT and INR. From the receiver operating characteristic analysis, PC, PS, and ATIII could significantly predict PE and its subtypes at certain cutoffs with high accuracies (area under the curve [AUC] ≥0.70). Most women with PE are in a hypercoagulable state with lower natural anticoagulants. PC, PS, and ATIII are good predictive and diagnostic markers of PE and its subtypes (early-onset PE [EO-PE] and late-onset PE [LO-PE]) and should be explored in future studies.

Risk for excessive anticoagulation during hemodialysis is associated with type of vascular access and bedside coagulation testing: Results of a cross-sectional study

Background

Recommendations and practice patterns for heparin dosing during hemodialysis show substantial heterogeneity and are scantly supported by evidence. This study assessed the variability in unfractionated heparin (UFH) dosing during hemodialysis and its clinical and biological anticoagulatory effects, and identified explanatory factors of heparin dosing.

Methods

Cross-sectional study assessing UFH dosing, coagulation tests - activated partial thromboplastin time (aPTT) and activated clotting time (ACT) before dialysis start, 1 h after start and at treatment end (4 h) - and measurement of residual blood compartment volume of used dialyzers.

Results

101 patients, 58% male, with a median dialysis vintage of 33 (6-71) months received hemodialysis using a total UFH dose of 9,306 ± 4,079 (range 3,000-23,050) IU/session. Use of a dialysis catheter (n = 56, 55%) was associated with a 1.4 times higher UFH dose (p < 0.001) irrespective of prior access function. aPTT increased significantly more than ACT both 1 h and 4 h after dialysis start, independent of the dialysis access used. 53% of patients with catheter access and ACT ratio < 1.5, 1 h after dialysis start had simultaneous aPTT ratios > 2.5. Similar findings were present at 1 h for patients with AVF/AVG and at dialysis end for catheter use. No clinically significant clotting of the extracorporeal circuit was noted during the studied sessions. Dialyzer's blood compartment volume was reduced with a median of 9% (6-20%) without significant effect of UFH dose, aPTT or ACT measurements and vascular access type.

Conclusion

UFH dose adaptations based on ACT measurements frequently result in excessive anticoagulation according to aPTT results. Higher doses of UFH are used in patients with hemodialysis catheters without evidence that this reduces dialyzer clotting.

Prothrombin Time-International Normalized Ratio Predicts the Outcome of Atrial Fibrillation Patients Taking Rivaroxaban

Background: Although direct oral anticoagulants (DOACs) for patients with atrial fibrillation (AF) are considered to be safe, over or under anticoagulation and increased bleeding or thromboembolic risk are still considered individually. We aimed to investigate whether there is an association between prothrombin time and international normalized ratio (PT-INR) or activated partial thromboplastin time (aPTT) ratio, and the risks of ischemic stroke/systemic embolism (IS/SE) and major bleeding among AF patients taking rivaroxaban or dabigatran. Methods: This multi-center cohort study in Taiwan included 3192 AF patients taking rivaroxaban and 958 patients taking dabigatran for stroke prevention where data about PT-INR and aPTT were available. Results: For patients treated with rivaroxaban, a higher INR level was not associated with a higher risk of major bleeding compared to an INR level < 1.1. The risk of IS/SE was lower for patients having an INR ≥ 1.5 compared to those with an INR < 1.1 (aHR:0.57; [95%CI: 0.37−0.87]; p = 0.01). On-label dosing of rivaroxaban and use of digoxin were independent factors associated with an INR ≥ 1.5 after taking rivaroxaban. For patients taking dabigatran, a higher aPTT ratio was not associated with a higher risk of major bleeding. The risk of IS/SE was lower for patients having an aPTT ratio of 1.1−1.2 and 1.3−1.4 than those with an aPTT ratio < 1.1. Conclusions: In AF patients, rivaroxaban with an INR ≥ 1.5 was associated with a lower risk of IS/SE. PT-INR or aPTT ratios were not associated with bleeding events for rivaroxaban or dabigatran. INR may help predict the outcome of AF patients who take rivaroxaban.

Intravenous Thrombolysis for Acute Ischemic Stroke in Patients with End-Stage Renal Disease on Hemodialysis: A Narrative Review

OBJECTIVES

Acute ischemic stroke (AIS) is a significant and devastating complication in patients with end-stage renal disease on hemodialysis (ESRD/HD). Since one-third of AIS in ESRD/HD patients occurs during or soon after dialysis, patients are more likely to present within the time window when intravenous thrombolysis (IVT) can be performed. IVT may improve prognosis in ESRD/HD patients with AIS. However, ESRD/HD patients have been excluded from large trials and may have been withheld from IVT due to concerns about bleeding complications. To date, there is no clear evidence and firm guidance on the safety and efficacy of IVT in ESRD/HD patients with AIS. This narrative review aimed to evaluate critical scientific data on the benefits and risks of IVT use in patients with ESRD/HD and AIS.

MATERIALS AND METHODS

We searched the electronic database of PubMed for studies evaluating the relationship between AIS, ESRD/HD, and IVT. Reference sections and additional publications were also searched manually. Studies on AIS in patients with ESRD/HD requiring maintenance dialysis that referred to IVT were included.

RESULTS

In total, 560 studies were found in the PubMed electronic database during the period covered, of which 10 met the selection criteria. IVT for AIS in ESRD/HD patients could improve neurological outcomes and be safely performed even with the possibility of hemorrhagic complications associated with hypertension. Despite the high complication and mortality rates in ESRD/HD patients with AIS after IVT, the association with IVT was unclear.

CONCLUSIONS

IVT for AIS in ESRD/HD patients may improve outcomes and should not be withheld based solely on ESRD/HD status.

A Patient with Severe Fever with Thrombocytopenia Syndrome, Activated Partial Thromboplastin Time Prolongation, and Transient Antiphospholipid Antibodies

A prolonged activated partial thromboplastin time (APTT) is observed in patients with severe fever with thrombocytopenia syndrome (SFTS) and is one of the risk factors for severe disease. The mechanism underlying a prolonged APTT is largely unknown. The presence of antiphospholipid (aPL) antibodies in various viral infections has been documented but never reported in a patient with SFTS. We herein report the first SFTS patient with APTT prolongation and concurrent transiently positive aPL antibodies (lupus anticoagulants and anticardiolipin antibodies) with no coagulation factor deficiency.

Biomarkers of Coagulation and Inflammation in Dogs after Randomized Administration of 6% Hydroxyethyl Starch 130/0.4 or Hartmann's Solution

Synthetic colloid fluids containing hydroxyethyl starch (HES) have been associated with impairment of coagulation in dogs. It is unknown if HES causes coagulation impairment in dogs with naturally occurring critical illness. This study used banked plasma samples from a blinded, randomized clinical trial comparing HES and balanced isotonic crystalloid for bolus fluid therapy in 39 critically ill dogs. Blood was collected prior to fluid administration and 6, 12, and 24 h thereafter. Coagulation biomarkers measured at each time point included prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen concentration, and the activities of coagulation factors V, VII, VIII, IX, and X, von Willebrand factor antigen, antithrombin, and protein C. Given the links between coagulation and inflammation, cytokine concentrations were also measured, including interleukins 6, 8, 10, and 18, keratinocyte-derived chemokine, and monocyte chemoattractant protein-1. Data were analyzed with linear mixed effects models. No significant treatment-by-time interactions were found for any biomarker, indicating that the pattern of change over time was not modified by treatment. Examining the main effect of time showed significant changes in several coagulation biomarkers and keratinocyte-derived chemokines. This study could not detect evidence of coagulation impairment with HES.

Anticoagulation Monitoring with Activated Partial ThromboPlastin Time and Anti-Xa Activity in Intensive Care Unit Patients: Interest of Thrombin Generation Assay

Current guidelines recommend monitoring the anticoagulant effect of unfractionated heparin (UFH) by measuring anti-Xa activity rather than activated partial thromboplastin time (aPTT) in intensive care unit (ICU) patients. The primary objective of this study was to evaluate the correlation of aPTT, anti-Xa activity, and thrombin generation in UFH-treated ICU patients. A prospective observational pilot study was conducted in adult surgical ICU patients treated with UFH. aPTT and anti-Xa activity were monitored daily. The therapeutic target was aPTT between 50 s and 84 s, and/or anti-Xa between 0.3 and 0.7 U/mL. Correlation among aPTT, anti-Xa activity, and thrombin generation was determined by measuring endogenous thrombin potential (ETP), with the inflammatory response evaluated. C-reactive protein (CRP) was used as a marker of inflammatory response. The plasma of 107 samples from 30 ICU patients was analyzed. The correlation between aPTT and anti-Xa activity was 0.66, CI95% [0.54;0.76] (p < 0.0001). Although thrombin generation, aPTT, and anti-Xa were correlated with inflammatory responses, the correlation was higher with thrombin generation and anti-Xa activity compared to aPTT. When aPTT was in a therapeutic range, a low thrombin generation was observed but was 50% inhibited when anti-Xa was in a therapeutic range. Coagulation testing with aPTT, anti-Xa correlated with thrombin generation. A 50% decrease in thrombin generation was observed when anti-Xa was within a therapeutic range. Further work is needed to evaluate coagulation biomarker responses and clinical outcomes in specific ICU populations.

Predicting Therapeutic Response to Unfractionated Heparin Therapy: Machine Learning Approach

Background

Unfractionated heparin (UFH) is an anticoagulant drug that is considered a high-risk medication because an excessive dose can cause bleeding, whereas an insufficient dose can lead to a recurrent embolic event. Therapeutic response to the initiation of intravenous UFH is monitored using activated partial thromboplastin time (aPTT) as a measure of blood clotting time. Clinicians iteratively adjust the dose of UFH toward a target, indication-defined therapeutic aPTT range using nomograms, but this process can be imprecise and can take ≥36 hours to achieve the target range. Thus, a more efficient approach is required.

Objective

In this study, we aimed to develop and validate a machine learning (ML) algorithm to predict aPTT within 12 hours after a specified bolus and maintenance dose of UFH.

Methods

This was a retrospective cohort study of 3019 patient episodes of care from January 2017 to August 2020 using data collected from electronic health records of 5 hospitals in Queensland, Australia. Data from 4 hospitals were used to build and test ensemble models using cross-validation, whereas data from the fifth hospital were used for external validation. We built 2 ML models: a regression model to predict the aPTT value after a UFH bolus dose and a multiclass model to predict the aPTT, classified as subtherapeutic (aPTT <70 seconds), therapeutic (aPTT 70-100 seconds), or supratherapeutic (aPTT >100 seconds). Modeling was performed using Driverless AI (H2O), an automated ML tool, and 17 different experiments were iteratively conducted to optimize model accuracy.

Results

In predicting aPTT, the best performing model was an ensemble with 4x LightGBM models with a root mean square error of 31.35 (SD 1.37). In predicting the aPTT class using a repurposed data set, the best performing ensemble model achieved an accuracy of 0.599 (SD 0.0289) and an area under the receiver operating characteristic curve of 0.735. External validation yielded similar results: root mean square error of 30.52 (SD 1.29) for the aPTT prediction model, and accuracy of 0.568 (SD 0.0315) and area under the receiver operating characteristic curve of 0.724 for the aPTT multiclassification model.

Conclusions

To the best of our knowledge, this is the first ML model applied to intravenous UFH dosing that has been developed and externally validated in a multisite adult general medical and surgical inpatient setting. We present the processes of data collection, preparation, and feature engineering for replication.

Validation of high concentrated thrombin time assay for unfractionated heparin monitoring

Background

The high concentrated thrombin time (hcTT), a thrombin time modified by increasing the thrombin concentration, is a possible alternative assay to activated partial thromboplastin time (aPTT) in unfractionated heparin (UFH) monitoring. This study aimed to determine the optimal thrombin concentration used in the hcTT assay for UFH monitoring.

Methods

A total of 30 blood samples obtained from healthy volunteers were included in this study. Thrombin concentrations of 10.0, 15.0, 20.0, and 25.0 IU/ml were used in the hcTT assay. The consistency between the hcTT and anti‐FXa assays was evaluated. To validate the hcTT assay, linearity, repeatability, reproducibility, and diagnostic performance of the assay were assessed.

Results

The hcTT assay using thrombin concentration of 15.0 IU/ml showed a strong correlation to the anti‐FXa assay with R² of 0.72 and the Spearman's correlation coefficient (r_s) of 0.97 (95% CI, 0.96–0.98). Within‐run and day‐to‐day run variabilities of the assay were satisfactory (all coefficients of variation <10%). We found an excellent correlation between the results which were measured using different reagents with intra‐ or inter‐laboratory instruments. Notably, as compared to the aPTT assay, the hcTT assay showed a significantly better performance in identifying the samples which contain UFH at the supratherapeutic level, with an AUC of 0.97 vs. 0.91, p = 0.049.

Conclusion

The hcTT assay can be used as an alternative assay for UFH therapy monitoring. A further study using clinical samples is recommended to confirm the appropriateness of the hcTT assay for clinical application.

Effect of Initial Anticoagulation Targets on Bleeding and Thrombotic Complications for Patients With Acute Respiratory Distress Syndrome Receiving Extracorporeal Membrane Oxygenation

OBJECTIVE

To evaluate the effect of anticoagulation targets and intensity on bleeding events, thrombotic events, and transfusion requirements in patients with acute respiratory distress syndrome (ARDS) receiving venovenous extracorporeal membrane oxygenation (ECMO) and continuous-infusion heparin.

DESIGN

A retrospective cohort study.

SETTING

At a single-center, large academic medical center.

PARTICIPANTS

One hundred thirty-six critically ill patients.

INTERVENTIONS

The following three therapeutic targets were implemented over time and evaluated: (1) no protocol (September 2013-August 2016): no standardized anticoagulation protocol or transfusion thresholds; (2) <50 seconds (September 2016-January 2018): standardized activated partial thromboplastin time (aPTT) goal of <50 seconds, maximum heparin infusion rate of 1,200 units/h, transfusion threshold of hemoglobin (Hgb) <8 g/dL; and (3) 40-to-50 seconds (February 2018-December 2019): aPTT goal of 40-to-50 sec, no maximum heparin infusion rate, transfusion threshold of Hgb <7 g/dL.

MEASUREMENTS AND MAIN RESULTS

Continuous variables were compared using the Kruskal-Wallis test, and categorical variables were compared using Fisher exact tests. The primary endpoint, an incidence of at least 1 bleeding event, was highest in the no-protocol group though not statistically different among groups (39.3% v 26.7% v 34%, p = 0.5). Thrombotic complications were similar. The median units of packed red blood cells transfused were highest in the no-protocol group (3 v 2 v 0.5, p < 0.001).

CONCLUSION

Anticoagulation protocols standardizing aPTT goals to <50 or 40-to-50 seconds may be a reasonable strategy for patients receiving venovenous ECMO for ARDS. More restrictive hemoglobin transfusion thresholds, in combination with lower aPTT targets, may be associated with a reduction in transfusion requirements.

Haematological variables and risk of future venous thromboembolism in the British Regional Heart Study on men. Combined D-dimer and APTT as a predictive test for thromboembolism?

We examined the associations between haematological and inflammatory variables with future venous thromboembolism (VTE), in 3494 men aged 60-79 years, with no previous history of VTE or myocardial infarction, who were not receiving oral anticoagulants. After a mean follow-up period of 18 years, there were 149 confirmed cases of fatal or non-fatal VTE (deep vein thrombosis and/or pulmonary embolism). Among classical cardiovascular risk factors, only obesity and cigarette smoking were associated with VTE risk. After adjustment for age, obesity and smoking, VTE risk was associated with coagulation factor VIII, factor IX, von Willebrand factor (VWF), activated partial thromboplastin time (APTT), and fibrin D-dimer. Hazard ratios (95% CI) for top to bottom quarters (bottom to top for APTT), were respectively 2.17 (1.37, 3.44), 2.15 (1.30, 3.53), 2.02 (1.27, 3.22), 2.43 (1.47, 4.02) and 3.62 (2.18, 6.08). The 11% of men with both the shortest APTT and highest D-dimer combined had a 5.02 (2.37, 10.62) higher risk of VTE. VTE risk was not associated with fibrinogen, factor VII or activated protein C resistance; full blood count variables or with inflammatory markers, plasma viscosity, C-reactive protein or interleukin-6. The combination of D-dimer and APTT merits evaluation as an adjunct to VTE risk prediction scores.

Pharmacological Investigation of Asphodelus tenuifolius Cav. for its Potential Against Thrombosis in Experimental Models

Background

Thrombosis is a major disorder which is an outcome of an imbalance in the hemostatic system that develop undesirable blood clot and hinder blood circulation.

Purpose

The current study was designed to verify the potential of aqueous methanolic crude extract of Asphodelus tenuifolius Cav. (At.Cr), used traditionally as remedy in circulatory problems.

Research Design

Antioxidant activity, FTIR, and HPLC analysis were performed. In-vitro clot lysis assay was performed on human blood samples, and in-vivo acute pulmonary thromboembolism model was developed by administering the mixture of collagen and epinephrine in tail vein of mice. Carrageenan-induced thrombosis and FeCl₃-induced carotid arterial thrombosis models were developed in rats.

Results

At.Cr demonstrated significant increase in lysis of human blood clot. Bleeding and clotting times were increased dose-dependently. Lungs histology showed clear alveolar spaces with decreased red blood cells congestion. Reduction in infarcted tail length, augmentation in prothrombin time, and activated partial thromboplastin time with decrease in platelet count were observed. At.Cr also prolonged the arterial occlusion time and reduced the weight of thrombus and TXB₂ levels dose-dependently.

Conclusions

The results demonstrated the antithrombotic and thrombolytic potential of At.Cr due to activation of coagulation factors through extrinsic and intrinsic pathways.

Comparison of Managing Factor Xa Inhibitor to Unfractionated Heparin Transitions by aPTT Versus a Treatment Guideline Utilizing Heparin Anti-Xa Levels

BACKGROUND

There are inadequate data on the optimal strategy for transitioning factor Xa inhibitors (FXai; apixaban, rivaroxaban) to unfractionated heparin (UFH) infusions.

OBJECTIVE

In patients transitioning from an FXai to an UFH infusion, this study compared the safety and efficacy of monitoring UFH infusions using an activated partial thromboplastin time (aPTT) titration scale versus utilizing an UFH-calibrated anti-Xa titration scale aided by a novel institutional guideline.

METHODS

A retrospective cohort analysis was conducted on adult patients transitioning from an FXai to an UFH infusion at 2 medical centers from June 1, 2018, to November 1, 2020. One institution utilized aPTT while the other institution primarily used UFH-calibrated anti-Xa. The primary endpoint was a composite of death, major bleeding, or new thrombosis during the hospitalization with a planned noninferiority analysis. Secondary outcomes were also collected including the amount and duration of UFH administered between cohorts.

RESULTS

The incidence rate of the primary composite endpoint was 6.3% in the anti-Xa group and 11% in the aPTT group (P < 0.001 for noninferiority, P = 0.138 for superiority) meeting noninferiority criteria. No statistical differences were seen in new thrombosis, major bleeding, or any bleeding.

CONCLUSION AND RELEVANCE

This represents the first report of a comparison between aPTT versus anti-Xa monitoring in relation to clinical outcomes for patients transitioning from an FXai to an UFH infusion. A transition guideline primarily utilizing an UFH-calibrated anti-Xa assay appears to be a safe alternative to aPTT monitoring and can aid facilities in the management of patients during these complex transitions.

Influence of Oral Dipping Tombak Smokeless Tobacco on Coagulation Profile and Platelet Counts

The goal of this paper is to investigate the influence of oral dipping of Tombak Smokeless Tobacco (SLT) on prothrombin time (PT), activated partial thromboplastin time (APTT), international normalized ratio(INR) values, and platelet counts (PLTs), in Sudanese Tombak users. An analytical cross-sectional study was conducted at Kosti health insurance hospital, Sudan, in 2019. According to the inclusion and exclusion criteria, 100 adult users of oral Tombak for three or more years were chosen randomly as a study group. Another 100 matched healthy individuals who never used Tombak were randomly selected as a comparative group. Venous blood specimens were collected in ethylene diamine tetra-acetic acid (EDTA) containers for the PLT counts using the automated haematology analyser (Sysmex, Tokyo, Japan XK-21SYSMEX) and in trisodium citrate anti-coagulant containers for coagulation tests using a co-agulometer machine analyser. Our findings show a significant decrease in PLT count mean values in the Tombak users group (212.1 × 103/mm3 ± 74.3 × 103/mm3) compared with the non-taking Tombak group mean values (243.2 × 103/mm3 ± 83.0 × 103/mm3), (p < 0.006). Both PT and APTT were significantly prolonged in Tombak users (16.03 ± 1.22 s vs. 14.44 ± 0.557 s), p < 0.001 for PT, and (41.62 ± 7.28 s vs. 34.99 ± 4.02 s), (p < 0.001) for APTT. INR mean values were significantly longer in Tombak users (1.11 ± 0.096) vs. (1.07 ± 0.66; p < 0.001). Multiple linear regression analysis findings show a significant impact of the four investigated variables, including duration of taking Tombak, age, and frequency of taking Tombak per day (p < 0.001). In conclusion, using Tombak a Smokeless Tobacco (SLT) for a long period significantly affect Platelet counts and coagulation profile.

Reference intervals for coagulation tests in adults with different ABO blood types

INTRODUCTION

Coagulation tests are affected by many factors, such as age, race, and gestation. Although coagulation test results vary by ABO blood type, reference intervals of different ABO blood groups remain to be determined. This study aims to investigate the reference ranges of coagulation tests for different ABO blood groups in the Han population in South China.

METHODS

A retrospective study was conducted in the First Affiliated Hospital of Shantou University Medical College. In all, 9600 individuals aged between 20 and 79 years were included. Coagulation tests, including prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (aPTT), thrombin time, and fibrinogen, were performed.

RESULTS

There was a significant difference in PT, INR, and aPTT among ABO blood groups. PT and INR varied slightly between ABO blood groups. There was a higher aPTT value in individuals in the O blood group than in those in non-O blood groups, in both males and females across the included age range. No differences were found in thrombin time and fibrinogen between the ABO blood groups.

CONCLUSION

The study provides reference data on coagulation tests from ABO blood groups in South China. The established reference intervals specific to ABO blood type, sex, and age may improve clinical decisions based on coagulation tests.

A multi-laboratory assessment of lupus anticoagulant assays performed on the ACL TOP 50 family for harmonized testing in a large laboratory network

Introduction

Lupus anticoagulant (LA) testing is commonly performed within hemostasis laboratories, and the ACL TOP 50 family of instruments represent a new “single platform” of hemostasis instrumentation. Our aim was to evaluate these instruments and manufacturer reagents or alternatives for utility in LA testing.

Methods

Comparative evaluations of LA testing using newly installed ACL TOPs 550 and 750 as well as comparative assessments with existing “reference,” predominantly Stago, instrumentation, and reagents. Evaluations comprised both dilute Russell viper venom time (dRVVT) and activated partial thromboplastin time (APTT)‐based assays. Establishment of normal reference ranges (NRR).

Results

The HemosIL dRVVT‐based assays showed good comparability with the existing Stago reference method (R > 0.9) and could be considered as verified as fit for purpose. A variety of APTT assays was additionally evaluated for LA utility, and we identified from the assessment good utility of a non‐Werfen solution in Hyphen BioMed Cephen reagents. NRR were established based on ≥120 normal individual plasma samples.

Conclusion

This evaluation of LA reagents on ACL TOP 50 Family instruments identified overall acceptable performance of both dRVVT (Werfen solution) and APTT (non‐Werfen solution) to enable harmonization of LA testing in our large network.

Pseudo-pheochromocytoma due to obstructive sleep apnea: a case report

SUMMARY

Obstructive sleep apnea (OSA) is a condition of intermittent nocturnal upper airway obstruction. OSA increases sympathetic drive which may result in clinical and biochemical features suggestive of pheochromocytoma. We present the case of a 65-year-old male with a 2.9-cm left adrenal incidentaloma on CT, hypertension, symptoms of headache, anxiety and diaphoresis, and persistently elevated 24-h urine norepinephrine (initially 818 nmol/day (89-470)) and normetanephrine (initially 11.2 µmol/day (0.6-2.7)). He was started on prazosin and underwent left adrenalectomy. Pathology revealed an adrenal corticoadenoma with no evidence of pheochromocytoma. Over the next 2 years, urine norepinephrine and normetanephrine remained significantly elevated with no MIBG avid disease. Years later, he was diagnosed with severe OSA and treated with continuous positive airway pressure. Urine testing done once OSA was well controlled revealed complete normalization of urine norepinephrine and normetanephrine with substantial symptom improvement. It was concluded that the patient never had a pheochromocytoma but rather an adrenal adenoma with biochemistry and symptoms suggestive of pheochromocytoma due to untreated severe OSA. Pseudo-pheochromocytoma is a rare presentation of OSA and should be considered on the differential of elevated urine catecholamines and metanephrines in the right clinical setting.

LEARNING POINTS

Obstructive sleep apnea (OSA) is a common condition among adults. OSA may rarely present as pseudo-pheochromocytoma with symptoms of pallor, palpitations, perspiration, headache, or anxiety. OSA should be considered on the differential of elevated urine catecholamines and metanephrines, especially in patients with negative metaiodobenzylguanidine (MIBG) scan results.

Acquired Factor VIII Inhibitors: A Case Study

The physiology of hemostasis is one of high complexity that involves the initiation, amplification, and propagation of the many moving parts of the hemostatic system and its regulatory mechanisms. It is imperative that clinical laboratory professionals have a strong understanding of the many intricacies of the physiology of coagulation and its in vitro testing. An elongated activated partial thromboplastin time can have several causes, and the correct cause must be elucidated in a timely manner for proper treatment. A mixing study with normal pooled plasma should be performed to evaluate for the presence of an inhibitor vs factor deficiency. Factor inhibitors, specifically factor VIII in this case study, should be titered so that the clinician can decide which treatment may work best for the patient. Continued monitoring of factor levels and inhibitor titers should be conducted to follow the resolution or progression of inhibitor presence.

High Perceived Stress May Shorten Activated Partial Thromboplastin Time and Lead to Worse Clinical Outcomes in Patients With Coronary Heart Disease

Objective: To determine the association of perceived stress with coagulation function and their predictive values for clinical outcomes. Methods: This prospective cohort study derived from a cross-sectional study for investigating the psychological status of inpatients with suspicious coronary heart disease (CHD). In this study, the 10-item Perceived Stress Scale (PSS-10) as an optional questionnaire was used to assess the severity of perceived stress. Coagulation function tests, such as activated partial thromboplastin time (APTT), prothrombin time (PT), and fibrinogen were measured within 1 h after admission. Furthermore, 241 patients with CHD out of 705 consecutive inpatients were included in the analyses and followed with a median of 26 months for the clinical outcomes. Results: The patients in high perceived stress status (PSS-10 score > 16) were with shorter APTT (36.71 vs. 38.45 s, p = 0.009). Shortened APTT ( ≤ 35.0 s) correlated with higher PSS-10 score (14.67 vs. 11.22, p = 0.003). The association of APTT with depression or anxiety was not found. Multiple linear models adjusting for PT estimated that every single point increase in PSS-10 was relevant to approximately 0.13 s decrease in APTT (p = 0.001) regardless of the type of CHD. APTT (every 5 s increase: hazard ratio (HR) 0.68 [0.47-0.99], p = 0.041) and perceived stress (every 5 points increase: HR 1.31 [1.09-1.58], p = 0.005) could predict the cardiovascular outcomes. However, both predictive values would decrease when they were simultaneously adjusted. After adjusting for the physical clinical features, the associated of perceived stress on cardiac (HR 1.25 [1.04-1.51], p = 0.020) and composite clinical outcomes (HR 1.24 [1.05-1.47], p = 0.011) persisted. Conclusions: For the patients with CHD, perceived stress strongly correlates with APTT. The activation of the intrinsic coagulation pathway is one of the mechanisms that high perceived stress causes cardiovascular events. This hints at an important role of the interaction of mental stress and coagulation function on cardiovascular prognosis. More attention needs to be paid to the patients with CHD with high perceived stress.

Bleeding Versus Thrombotic Tendency in Young Children With Beta-Thalassemia Major

Introduction

Bleeding and thrombotic events are known to occur in beta-thalassemia major (BTM) patients and have been attributed to hepatic iron overload associated with multiple blood transfusions. We evaluated hemostatic parameters in children with BTM who had no previous history of bleeding or thrombotic episodes.

Materials and Methods

Hemostatic parameters including prothrombin time (PT), activated partial thromboplastin time (APTT), platelet aggregation, protein C and S, iron profile, and liver function tests were evaluated in 54 children (median age = 12 months, age range = 4-144 months) with BTM and 15 age and sex-matched controls.

Results

The mean PT and APTT of patients were significantly higher (P=0.016 and P <.001) than that of controls. Mean protein C, protein S activity and platelet aggregability with adenosine 5-diphosphate (ADP) as an agonist in patients were significantly lower (P <.001, P <.001 and P=0.007, respectively) than that in controls. Mean serum ferritin in BTM children was not significantly elevated to be associated with hepatic dysfunction.

Conclusion

Deranged hemostatic parameters indicative of bleeding and thrombotic tendencies are observed in BTM children from an early age and may not be solely due to hyperferritinemia-associated hepatic dysfunction. Despite the presence of deranged hemostatic parameters, a state of balance exists between bleeding and thrombosis, and an imbalance may lead to bleeding or thrombotic events at a later age.

Successful treatment of acquired haemophilia A

Összefoglaló. A szerzett haemophilia A ritka autoimmun betegség, melyben gátlótest képződik a VIII. véralvadási faktor ellen. Az inhibitor véralvadásra gyakorolt hatása súlyos, életet veszélyeztető vérzéses állapotot idéz elő. A beteg élete a gyors diagnózison múlik: a jellemző klinikai kép mellett a megnyúlt, normálplazmával nem korrigálható aktivált parciális tromboplasztinidő megléte esetén a kórkép alapos gyanúja merül fel. Egy súlyos vérszegénység miatt kórházunkba beutalt nőbeteg esetében a szerzett haemophilia A a felvételt követő napon már diagnosztizálásra került. A vérzés megszüntetésére aktivált protrombinkomplex-koncentrátumot alkalmaztunk, valamint immunszuppresszív terápiát vezettünk be. A kórkép korai felismerése és a megfelelő kezelés azonnali megkezdése a beteg gyógyulását eredményezte. Esetünkkel arra szeretnénk felhívni a figyelmet, hogy a szerzett haemophilia A gyors diagnózisa egyszerű, könnyen hozzáférhető véralvadási paraméter, az aktivált parciális tromboplasztinidő meghatározásán és nem korrigálható megnyúlásának felismerésén múlik. Orv Hetil. 2021; 162(49): 1977-1981. Summary. Acquired haemophilia A is a rare autoimmune disorder, in which antibodies are formed against coagulation factor VIII. The effect of the inhibitor on blood clotting results in severe, life-threatening bleeding diathesis. The patient's life depends on the rapid diagnosis: besides the characteristic clinical presentation, a prolonged activated partial thromboplastin time, which is not corrigible with normal plasma, suggests the existence of the disorder. In the case of the female patient who was referred to our hospital due to severe anaemia, acquired haemophilia A was diagnosed rapidly, the day after her admission. We used activated prothrombin complex concentrate to stop the bleeding, and introduced immunosuppressive therapy. The early recognition of the disease and immediate initiation of adequate treatment resulted in the patient's full recovery. With our case presentation, we would like to draw attention to the fact that the rapid diagnosis of acquired haemophilia A depends on the determination of a simple, easily accessible coagulation parameter, the activated partial thromboplastin time and on the immediate recognition of its incorrigible prolongation. Orv Hetil. 2021; 162(49): 1977-1981.

Role of Coagulation Profile in Predicting Disease Severity Among Patients of COVID-19

Background

Coronavirus disease 19 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), affects the coagulation cascade. In this retrospective study, we aimed to analyze the association of different coagulation parameters including that of D-dimer, fibrinogen, prothrombin time (PT), and activated partial thromboplastin time (aPTT) with severity in COVID-19 patients.

Methodology

A total of 90 patients positive for SARS-CoV-2 on real-time reverse transcription-polymerase chain reaction (rRT-PCR) were included in the study. The patients were categorized as severe and non-severe, and their D-dimer, fibrinogen, PT, and aPTT values on admission were evaluated. The association of the coagulation parameters with disease severity was analyzed by independent t-test and Chi-square test. The cut-off values of these parameters were calculated to predict the disease severity by receiver operator characteristic (ROC) curve.

Results

Out of 90 patients admitted, 42 patients were categorized as severe and the rest 48 patients were categorized as non-severe. D-dimer, fibrinogen, and PT in the severe group were significantly higher than the non-severe group with p-values of <0.001, 0.005, and <0.001, respectively. Cut-off values of 0.99 mg/L for D-dimer,349.5 mg/dL for fibrinogen, and 13.05 seconds for PT were predictive of disease severity among COVID-19 patients.

Conclusion

Severe COVID-19 patients showed significantly higher levels of D-dimer and fibrinogen and prolongation of PT as compared to non-severe COVID-19 patients. Higher levels of D-dimer and fibrinogen, and prolonged PT are predictive of increased disease severity among COVID-19 patients.

Monitoring of different factor VIII replacement products using a factor VIII one-stage clotting assay on cobas t 511/711 analysers

INTRODUCTION

Recombinant coagulation factor VIII (FVIII) products are the standard of care for patients with haemophilia A. The development of modified FVIII products has provided benefit for patients but presented challenges for monitoring FVIII activity.

AIM

This single-centre study evaluated the Roche FVIII one-stage clotting assay (OSA) in measuring FVIII activity in plasma samples spiked with seven FVIII products at clinically relevant concentrations.

METHODS

FVIII-deficient plasma samples were spiked with two batches of recombinant FVIII products (octocog alfa, moroctocog alfa, simoctocog alfa, efmoroctocog alfa, damoctocog alfa pegol, rurioctocog alfa pegol, lonoctocog alfa) at 1-120 IU/dL FVIII activity, according to their labelled potency. Measurement was conducted on the cobas t 511/711 analysers using the Roche FVIII OSA and the Technoclone TECHNOCHROM FVIII:C chromogenic substrate assay (CSA).

RESULTS

Using the OSA, FVIII activity was close to labelled potency for most analysed FVIII products including a recombinant FVIII Fc fusion protein. PEGylated FVIII product, damoctocog alfa pegol, was marginally above and single-chain product, lonoctocog alfa, below the predefined acceptance criteria: for FVIII activity < 25 IU/dL: ± 5 IU/dL; for FVIII activity ≥ 25 IU/dL: ± 20% (relative). The different principles of OSA and CSA led to discrepancies in the estimation of all analysed FVIII products. Additionally, in vitro recovery was increased at lower levels of FVIII activity using the OSA, whereas recovery was more consistent using the CSA.

CONCLUSION

These data allow the interpretation of FVIII activity results for different FVIII products using the Roche FVIII OSA on the cobas t 511/711 analysers.

Association of coagulation disturbances with severity of COVID-19: a longitudinal study

OBJECTIVES

Coagulation dysfunction is an evident factor in the clinical diagnosis and treatment of patients with coronavirus disease 2019 (COVID-19), appearing even in COVID-19 patients with normal inflammation indices. Therefore, this study aimed to analyze the characteristics of coagulation function indices in COVID-19 patients to investigate possible mechanisms through the comparison of non-severe and severe COVID-19 patients.

METHODS

We included 143 patients whose clinical characteristics, coagulation function, and other indices such as inflammatory factors were collected and compared based on disease severity.

RESULTS

Activated partial thromboplastin time (APTT), D-dimer, and fibrinogen levels were evidently higher in the severe group than in the non-severe group. Among non-severe COVID-19 patients, the aforementioned indicators depicted increasing trends, but the fibrinogen level alone was higher than normal. However, in severe COVID-19 patients, values of all three indices were higher than normal. In severe COVID-19 patients, fibrinogen and D-dimer were correlated with several inflammation indices during the early stage of the disease. However, no correlation between fibrinogen and inflammatory factors was observed in non-severe COVID-19 patients at any time point.

DISCUSSION

Results revealed that the hypercoagulability tendency of severe COVID-19 patients was more evident. The relationship between coagulation function and inflammatory factors showed that changes in coagulation function in severe COVID-19 patients may be related to abnormal increase in inflammatory factors at an early stage; however, in non-severe COVID-19 patients, there might be other factors leading to abnormal coagulation.

CONCLUSION

Inflammatory factors were not the only cause of abnormal coagulation function in COVID-19 patients.