Illustrated State-of-the-Art Capsules of the ISTH 2023 Congress.

This year's Congress of the International Society of Thrombosis and Haemostasis (ISTH) took place in person in Montréal, Canada, from June 24-28, 2023. The conference, held annually, highlighted cutting-edge advances in basic, translational, population and clinical sciences relevant to the Society. As for all ISTH congresses, we offered a special, congress-specific scientific theme; this year, the special theme was immunothrombosis. Certainly, over the last few years, COVID-19 infection and its related thrombotic and other complications have renewed interest in the concepts of thromboinflammation and immunothrombosis; namely, the relationship between inflammation, infection and clotting. Other main scientific themes of the Congress included Arterial Thromboembolism, Coagulation and Natural Anticoagulants, Diagnostics and Omics, Fibrinolysis and Proteolysis, Hemophilia and Rare Bleeding Disorders, Hemostatic System in Cancer, Inflammation and Immunity, Pediatrics, Platelet Disorders, von Willebrand Disease and Thrombotic Microangiopathies, Platelets and Megakaryocytes, Vascular Biology, Venous Thromboembolism and Women's Health. Among other sessions, the program included 28 State-of-the-Art (SOA) sessions with a total of 84 talks given by internationally recognized leaders in the field. SOA speakers were invited to prepare brief illustrated reviews of their talks that were peer reviewed and are included in this article. These illustrated capsules highlight the major scientific advances with potential to impact clinical practice. Readers are invited to take advantage of the excellent educational resource provided by these illustrated capsules. They are also encouraged to use the image in social media to draw attention to the high quality and impact of the science presented at the Congress.

Multicenter evaluation of light transmission platelet aggregation reagents: communication from the ISTH SSC Subcommittee on Platelet Physiology.

BACKGROUND: Light transmission aggregation (LTA) is used widely by the clinical and research communities. Although it is a gold standard, there is a lack of interlaboratory harmonization. OBJECTIVES: The primary objective was to assess whether sources of activators (mainly adenosine diphosphate [ADP], collagen, arachidonic acid, epinephrine, and thrombin receptor activating peptide6) and ristocetin contribute to poor LTA reproducibility. The secondary objective was to evaluate interindividual variability of results to appreciate the distribution of normal values and consequently better interpret pathologic results. METHODS: An international multicenter study involving 28 laboratories in which we compared LTA results obtained with center-specific activators and a comparator that we supplied. RESULTS: We report variability in the potency (P) of activators in comparison with the comparator. Thrombin receptor activating peptide 6 (P, 1.32-2.68), arachidonic acid (P, 0.87-1.43), and epinephrine (P, 0.97-1.34) showed the greatest variability. ADP (P, 1.04-1.20) and ristocetin (P, 0.98-1.07) were the most consistent. The data highlighted clear interindividual variability, notably for ADP and epinephrine. Four profiles of responses were observed with ADP from high-responders, intermediate-responders, and low-responders. A fifth profile corresponding to nonresponders (5% of the individuals) was observed with epinephrine. CONCLUSION: Based on these data, the establishment and adoption of simple standardization principles should mitigate variability due to activator sources. The observation of huge interindividual variability for certain concentrations of activators should lead to a cautious interpretation before reporting a result as abnormal. Confidence can be taken from the fact that difference between sources is not exacerbated in patients treated with antiplatelet agents.

Comparison of coagulation monitoring using ROTEM and Sonoclot devices in cardiac surgery: a single-center prospective observational study.

BACKGROUND: Viscoelastic tests (VETs) are recommended during cardiac surgery to monitor coagulation status and guide transfusion. We compared the results of two VETs, the Sonoclot Analyzer and the ROTEM Sigma. Agreement between viscoelastic tests' subdiagnoses and overall diagnosis severity was assessed. Correlations with conventional coagulation tests (CCT) and the discriminatory potential of numerical VET outputs for transfusion thresholds was determined. METHODS: Single-center, prospective observational study in a tertiary academic center. In fifty adult patients undergoing elective cardiac surgery, parallel Sonoclot, ROTEM and CCT analysis was performed before heparin, or after protamine or coagulation product administration. All patients completed the study, resulting in 139 data points. RESULTS: Agreement on the severity of coagulation disorders was acceptable (83%), but poor (27%) on the differentiation of the underlying causes. Correlations between ROTEM parameters and CCT were good (postprotamine: FIBTEM A5 (r2=0.90 vs. fibrinogen) and EXTEM-FIBTEM A5 difference (r2=0.81 vs. platelet count). Sonoclot correlated less (Clot Rate (r2=0.25 vs. fibrinogen) and Platelet Function (r2=0.43 vs. platelet count). This was reflected in the discriminatory potential of these parameters as found by linear mixed modelling. We suggest clinically useful grey zones for VET cutoff interpretation. CONCLUSIONS: ROTEM and Sonoclot accord well on the detection of severity of coagulation dysfunction, but not on the diagnosis of the underlying cause. ROTEM correlated more closely with CCT then Sonoclot. We propose a testing strategy that could lead to a cost-effective approach to the bleeding cardiac surgery patient.

Illustrated State-of-the-Art Capsules of the ISTH 2020 Congress.

The 2020 Congress of the International Society of Thrombosis and Haemostasis (ISTH) was held virtually July 12-15, 2019, due to the coronavirus disease 2019 pandemic. The congress convenes annually to discuss clinical and basic topics in hemostasis and thrombosis. Each year, the program includes State of Art (SOA) lectures given by prominent scientists. Presenters are asked to create Illustrated Capsules of their talks, which are concise illustrations with minimal explanatory text. Capsules cover major themes of the presentation, and these undergo formal peer review for inclusion in this article. Owing to the shift to a virtual congress this year, organizers reduced the program size. There were 39 SOA lectures virtually presented, and 29 capsules (9 from talks omitted from the virtual congress) were both submitted and successful in peer review, and are included in this article. Topics include the roles of the hemostatic system in inflammation, infection, immunity, and cancer, platelet function and signaling, platelet function disorders, megakaryocyte biology, hemophilia including gene therapy, phenotype tests in hemostasis, von Willebrand factor, anticoagulant factor V, computational driven discovery, endothelium, clinical and basic aspects of thrombotic microangiopathies, fibrinolysis and thrombolysis, antithrombotics in pediatrics, direct oral anticoagulant management, and thrombosis and hemostasis in pregnancy. Capsule authors invite virtual congress attendees to refer to these capsules during the live presentations and participate on Twitter in discussion. Research and Practice in Haemostasis and Thrombosis will release 2 tweets from @RPTHJournal during each presentation, using #IllustratedReview, #CoagCapsule and #ISTH2020. Readers are also welcome to utilize capsules for teaching and ongoing education.

Evaluation of the primary biliary cholangitis-related serologic profile in a large cohort of Belgian systemic sclerosis patients.

Background Systemic sclerosis (SSc) and primary biliary cholangitis (PBC) are autoimmune diseases that may occur concomitantly and are both strongly associated with disease-specific autoantibodies. This study investigated the prevalence and fine specificity of PBC-specific serology (PBC-Ab) and associations with the SSc-subtypes and SSc-specific antibodies as well as the association with cholestatic liver enzymes. Furthermore, three different techniques for the detection of PBC-Ab were compared. Methods Serum of 184 Belgian SSc patients with a known SSc-antibody profile, was analyzed for PBC-Ab (antimitochondrial antibodies [AMA], anti-Gp210, anti-Sp100 and anti-PML) using indirect immunofluorescence (IIF) analysis on human epithelioma-2000 (HEp-2000) cells (ANA-IIF, Immunoconcepts) and liver-kidney-stomach tissue sections (IIF-LKS) (Menarini), and a line immunoblot (LB) (EuroImmun). Alkaline phosphatase/γ-glutamyl transferase (ALP/GGT) were evaluated at time of first sampling (t0) and after 3 years of follow-up (t3). Results PBC-Ab were present in 13% of patients and significantly correlated with centromere antibodies (anti-CENP-B), but not correlated with the limited cutaneous SSc subgroup (lcSSc). The most frequent reactivities were AMA (11%, with 9% AMA-M2) and Sp-100 antibodies (5%), showing a major overlap. There was no relevant association between the presence of PBC-Ab and ALP or GGT elevation at t0 nor at t3. Detection of AMA with IIF-LKS is comparable to LB. ANA-IIF screening was less sensitive compared to LB. Conclusions A wide range of PBC-Ab is detectable in SSc in the absence of cholestatic liver enzyme elevations, even after 3 years of follow-up. However, as these antibodies may precede PBC-disease up to 10 years further prospective follow-up of our cohort will be necessary.

Antithrombotic prophylaxis for surgery-associated venous thromboembolism risk in patients with inherited platelet disorders. The SPATA-DVT Study.

Major surgery is associated with an increased risk of venous thromboembolism (VTE), thus the application of mechanical or pharmacologic prophylaxis is recommended. The incidence of VTE in patients with inherited platelet disorders (IPD) undergoing surgical procedures is unknown and no information on the current use and safety of thromboprophylaxis, particularly of low-molecular-weight-heparin in these patients is available. Here we explored the approach to thromboprophylaxis and thrombotic outcomes in IPD patients undergoing surgery at VTE-risk participating in the multicenter SPATA study. We evaluated 210 surgical procedures carried out in 155 patients with well-defined forms of IPD (VTE-risk: 31% high, 28.6% intermediate, 25.2% low, 15.2% very low). The use of thromboprophylaxis was low (23.3% of procedures), with higher prevalence in orthopedic and gynecological surgeries, and was related to VTE-risk. The most frequently employed thromboprophylaxis was mechanical and appeared to be effective, as no patients developed thrombosis, including patients belonging to the highest VTE-risk classes. Low-molecular-weight-heparin use was low (10.5%) and it did not influence the incidence of post-surgical bleeding or of antihemorrhagic prohemostatic interventions use. Two thromboembolic events were registered, both occurring after high VTE-risk procedures in patients who did not receive thromboprophylaxis (4.7%). Our findings suggest that VTE incidence is low in patients with IPD undergoing surgery at VTE-risk and that it is predicted by the Caprini score. Mechanical thromboprophylaxis may be of benefit in patients with IPD undergoing invasive procedures at VTE-risk and low-molecular-weight-heparin should be considered for major surgery.

Thrombomodulin and Endothelial Dysfunction: A Disease-Modifier Shared between Malignant Hypertension and Atypical Hemolytic Uremic Syndrome.

Thrombomodulin (TM) is an endothelial glycoprotein that is present in all blood vessels. Five percent of all patients with atypical hemolytic uremic syndrome (aHUS) have mutations in the gene coding for TM, with a peak presentation in young children. Mutations often translate into quantitative and qualitative abnormalities of this endothelial glycoprotein. Outcome of the TM-associated aHUS is relatively poor with frequent relapses after transplantation despite its membrane-bound character. We observed a woman presenting with malignant hypertension (MHT) and associated kidney, brain, cardiac, and hematological involvement with thrombotic microangiopathy on kidney biopsy. She had a documented mutation of the gene coding for TM, which was associated with both aHUS and an increased risk for venous and arterial thrombosis. As TM has anti-coagulant, anti-inflammatory, and cytoprotective properties and also attenuates alternative complement activation, this glycoprotein could play an active role in other diseases with endothelial involvement apart from aHUS. We discuss the potential role of TM in the pathophysiology of various endotheliopathies including MHT. We also provide a framework for future therapeutic options.

Isolated acquired factor VII deficiency: review of the literature.

OBJECTIVES: Isolated acquired factor VII (FVII) deficiency is a rare haemorrhagic disorder. We report what is currently known about the pathogenesis, clinical features, diagnosis, treatment and prognosis of acquired FVII deficiency. METHODS: We performed a literature search and included all articles published between 1980 and August 2015. RESULTS AND CONCLUSIONS: Acquired FVII deficiency has been reported in 42 patients. There are well-established clinical diseases associated with acquired FVII deficiency, most notably infections, malignancy and haematological stem cell transplantation. The exact pathogenesis of the diseases is still unknown, but different pathophysiological hypotheses have been suggested. The clinical manifestation of acquired FVII deficiency varies greatly in severity; asymptomatic course as well as severe life-threatening bleeding diathesis and fatal bleedings have been described.

Influence of dabigatran and rivaroxaban on routine coagulation assays. A nationwide Belgian survey.

The Belgian national External Quality Assessment Scheme performed a nationwide survey using lyophilised plasma samples spiked with dabigatran or rivaroxaban to demonstrate to the Belgian clinical laboratories how these drugs affect their routine coagulation assays prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen and antithrombin. Virtually all Belgian laboratories performing routine coagulation testing (189/192) participated in the survey. Both, dabigatran and rivaroxaban significantly prolonged the PT and aPTT in a concentration- and reagent-dependent manner. PT reagents were more influenced by rivaroxaban than by dabigatran and aPTT reagents more influenced by dabigatran than by rivaroxaban. Among PT reagents, Neoplastin R® was the most sensitive to rivaroxaban and Innovin® and Thromborel S® the least sensitive. Converting PT results to INR only increased the variability between reagents. Among aPTT reagents, Actin FSL® was the least sensitive to dabigatran while the other aPTT reagents showed slightly higher sensitivities. The presence of dabigatran led to falsely reduced fibrinogen concentrations when measured with a low thrombin concentration reagent. The presence of dabigatran caused an overestimation of the antithrombin level when measured with a thrombin-based activity assay and the presence of rivaroxaban an overestimation of the antithrombin level when measured with a FXa-based assay. Instrument-related differences were found for all tested parameters. In conclusion, this paper provides detailed information on the effect of dabigatran and rivaroxaban on routine coagulation assays as performed with a large number of reagent/instrument combinations.

Lymphoplasmacytic lymphoma exposed by haemoptysis and acquired von Willebrand syndrome.

We report on a 36-year-old man who presented to the emergency department with haemoptysis. Computed tomography (CT) of the thorax showed a pulmonary mass paramediastinal in the right upper lobe, with the density of a haematoma. Laboratory data demonstrated an absolute lymphocytosis of 5.900 × 10/l (normal range, 1.150-3.250 × 10/l) and a prolonged activated partial thromboplastin time (APTT) of 47.7 s (normal range, 28.0-39.0 s). A de novo diagnosis of lymphoplasmacytic lymphoma (Waldenström macroglobulinaemia) was made, complicated by an acquired von Willebrand syndrome (aVWS) as demonstrated by further laboratory investigations. In this case report, we present a case of aVWS with markedly prolonged APTT and haemoptysis that revealed an underlying Waldenström macroglobulinaemia.

Automated indirect immunofluorescence antinuclear antibody analysis is a standardized alternative for visual microscope interpretation.

BACKGROUND: Screening for antinuclear antibodies (ANA) is a basic tool in the serological work-up of systemic rheumatic disorders. Despite the emergence of alternative screening methods and the difficulties in standardization, indirect immunofluorescence (IIF) remains the recommended method for ANA detection. This study aimed to assess the reliability of automated ANA IIF analysis as a standardized alternative for the conventional manual approach. METHODS: ANA testing on HEp-2000 cells was performed on 304 consecutive routine sera, 28 serumbank samples displaying rare staining patterns, 219 samples of well-defined disease cohorts [141 systemic sclerosis (SSc), 13 polymyalgia rheumatica, 22 osteoarthritis, 5 ANCA-associated vasculitis and 38 spondyloarthritis] and 100 healthy donors. All samples were analyzed by automated IIF (Zenit G-sight), by conventional visual IIF microscopy and two ANA screening enzyme immunoassays (EIA). RESULTS: Automated and conventional ANA IIF analysis were comparable for negative/positive interpretation as well as intensity assessment (>90% agreement). In contrast, the accuracy of pattern recognition (26%) was limited. Likelihood ratios (LR) for SSc on results intervals of both Zenit G-sight and EIA increased with increasing level of positivity. Sensitivity within the SSc-associated antibody subsets was higher for Zenit G-sight (97%-100%) than EIA (10%-96%). A significant correlation between the quantitative result obtained by Zenit G-sight and the conventional end-point titer was found. CONCLUSIONS: The use of Zenit G-sight for automated ANA IIF analysis offers opportunities to improve standardization. However, a complementary role of the expert technicians remains, especially for pattern recognition and classification of uncertain/negative samples.

Fluoroenzymeimmunoassay to detect systemic sclerosis-associated antibodies: diagnostic performance and correlation with conventional techniques.

OBJECTIVES: Detection of systemic sclerosis-associated antibodies (SSc-Ab) in routine clinical practice is mostly restricted to anti-centromere and anti-Scl-70 antibodies. However, also other antinuclear antibodies have been shown to be valuable diagnostic and prognostic markers for the disease. The aim of this study was to evaluate the diagnostic performance of measuring the most prevalent SSc-Ab with fluoroenzymeimmunoassay (FEIA) as an alternative for the combined conventional techniques (CCT). METHODS: Sera from 144 consecutive systemic sclerosis (SSc) patients previously tested by CCT (indirect immunofluorescence on HEp-2000, western blotting, protein radio immunoprecipitation and a well-documented line immunoassay) and an additional group of 266 disease controls (80 rheumatoid arthritis, 58 systemic lupus erythematosus, 50 spondyloarthropathy, 48 osteoarthritis, 18 polymyalgia rheumatica and 12 ANCA-associated vasculitis) were retrospectively evaluated. Anti-centromere-B, anti-Scl-70, anti-RNA polymerase III and anti-PM/Scl antibodies were measured using FEIA. RESULTS: Using cut-off values corresponding with likelihood ratios larger than 10 FEIA obtained the following sensitivities: 45.1% for anti-centromere-B, 15.3% for anti-Scl-70, 5.6% for anti-RNA polymerase III and 2.1% for anti-PM/Scl. The overall agreement between combined conventional techniques and FEIA was good for all individual reactivities (kappa>0.800). The overall diagnostic sensitivity of 68.1% and diagnostic specificity of 98.1% were comparable to those obtained by CCT. CONCLUSIONS: FEIA testing for anti-centromere-B, anti-Scl-70, anti-RNA polymerase III and anti-PM/Scl-100 shows good performance and represents an accurate alternative for the time-consuming combined conventional techniques.

A clinical-laboratory approach contributing to a rapid and reliable diagnosis of heparin-induced thrombocytopenia.

INTRODUCTION: Heparin-induced thrombocytopenia (HIT) remains a very challenging diagnosis. The first objective of this study was to compare the performance of the ID-H/PF4 PaGIA with the Asserachrom HPIA ELISA. The main purpose was to evaluate the diagnostic utility of the combination of the H/PF4 PaGIA with the clinical "4T's" score as a screening strategy. MATERIALS AND METHODS: 102 patients with clinical suspicion of HIT were classified into risk groups using the 4T's score. The presence of HIT antibodies was assessed by two immunoassays and confirmed by a functional flow cytometric assay. RESULTS: Comparison of the ID-H/PF4 PaGIA with the Asserachrom HPIA ELISA demonstrated a comparable technical performance, being an excellent screening test to rule out HIT (negative predictive value or NPV=100%). According to the 4T's score, HIT was excluded in all low risk patients (NPV=100%). ELISA optical density levels were significantly different between all risk groups (P-values<0.01). In contrast, due to the low positive predictive value (22%) and weak positive likelihood ratio (2.6), a positive ID-H/PF4 PaGIA result did not considerably increase the probability of HIT. CONCLUSION: Our study confirms the combination of the 4T's score with the ID-H/PF4 PaGIA as a reliable strategy to rule out HIT. Yet, confirming positive ID-H/PF4 PaGIA results by flow cytometry within 1-2 h after blood sampling remains necessary. This novel clinical-laboratory approach can contribute in a rapid and reliable way to the definite diagnosis of HIT.

A 2-year retrospective analysis of laboratory testing for activated protein C resistance with a factor V-corrected activated partial thromboplastin time-based method.

The factor V-corrected activated protein C resistance assay is the test of choice to screen for the factor V Leiden mutation. During the past 2 years, local test results with the frequently used Coatest APCR kit were evaluated and compared with the results of DNA analysis, the 'gold standard'. Samples of 278 patients were analysed by both techniques. We were unable to confirm that factor V Leiden carriers can clearly be delineated from normal individuals with the Coatest APCR test. A ratio of 2.0 as the cut-off provides 99.0% sensitivity and 95.4% specificity.To evaluate the lupus anticoagulant interference, we retrospectively analysed 16 lupus anticoagulant-positive patients. In this study, two (12.5%) showed a false-positive activated protein C resistance result. Six out of 16 (37.5%) lupus anticoagulant-positive patients were also carriers of the factor V Leiden mutation. Four out of eight (50%) false-positive activated protein C resistance results presented with an abnormal baseline clotting time. In order to prevent reporting false-positive results, a maximum baseline clotting time (65.8 s) was calculated. A new scheme for interpreting activated protein C resistance ratios was proposed.