Communication from the ISTH SSC Subcommittee on Hemostasis and Malignancy: a meta-analysis to assess the risk of bleeding and thrombosis following chimeric antigen receptor T-cell therapy

BACKGROUND

Chimeric antigen receptor T-cell (CAR T-cell) therapy is increasingly utilized for treatment of hematologic malignancies. Hematologic toxicities including thrombosis and bleeding complications have been reported. Accurate estimates for thrombotic and bleeding outcomes are lacking.

OBJECTIVES

We performed a systematic review and meta-analysis in patients who received CAR T-cell therapy for an underlying hematologic malignancy with the objective to: a) assess the thrombosis and bleeding risk associated with CAR T-cell therapy, b) assess the impact of CRS and ICANS on the risks of thrombosis and bleeding, and c) assess the safety of anticoagulant or antiplatelet use in the period following treatment with CAR T-cell therapy.

METHODS

We searched MEDLINE, EMBASE, and Cochrane CENTRAL up to February 2022 for studies reporting thrombotic or bleeding outcomes in patients receiving CAR T-cell therapy. Pooled event rates were calculated using a random-effects model. We performed subgroup analyses stratified by follow-up duration, CAR T-cell target antigen, and underlying hematologic malignancy.

RESULTS

We included 47 studies with a total of 7040 patients. High heterogeneity between studies precluded reporting of overall pooled rates of thrombotic and bleeding events. In studies with follow-up duration of ≤6 months, the pooled incidence of venous thrombotic events was 2.4% (95% CI, 1.4%-3.4%; I2 = 0%) per patient-month, whereas the rate was 0.1% (95% CI, 0%-0.1%; I2 = 0%) per patient-month for studies with longer follow-up periods (>6 months). The pooled incidences of any bleeding events per patient-month in studies with follow-up duration of ≤6 months and >6 months were 1.9% (95% CI, 0.6%-3.1%; I2 = 78%) and 0.3% (95% CI: 0%-0.8%, I2 = 40%), respectively. Secondary analyses by CAR T-cell target antigen, underlying malignancy, and primary outcome of the studies did not reveal significant differences in the rates of thromboembolism, any bleeding events, or major bleeding events.

CONCLUSION

The risk of both thrombosis and bleeding following CAR T-cell therapy appears to be highest in the initial months following infusion.

Extensive splanchnic vein thrombosis after SARS-CoV-2 vaccination: A Vascular Liver Disease Group (VALDIG) initiative

BACKGROUND AND AIMS

Since the introduction of SARS-CoV-2 vaccines, several cases of vaccine-induced immune thrombocytopenia and thrombosis (VITT) have been described, especially cerebral vein thrombosis. We aimed to retrospectively collect all new cases of acute onset first or recurrent splanchnic vein thrombosis (SVT) following a recent SARS-CoV-2 vaccination within the Vascular Liver Disease Group network.

APPROACH AND RESULTS

New cases of SVT were identified from April 2021 to April 2022; follow-up was completed on December 31, 2022. Criteria to define VITT were derived from previous studies. Data from a pre-COVID cohort of patients with SVT (N=436) were used for comparison of clinical presentation, etiology, and outcome. Twenty-nine patients were identified with SVT occurring with a median of 11 days (range 2-76) after the first (48%), second (41%), or third (10%) vaccination (ChAdOx1 nCov-19 (n=12) or BNT162b2 (n=14), other (n=3) Only 2 patients(7%) fulfilled criteria for definite VITT. Twenty (69%) had SVT at multiple sites, including 4 (14%) with concomitant extra-abdominal thrombosis. Only 28% had an underlying prothrombotic condition, compared to 52% in the pre-COVID SVT cohort ( p =0.01). Five patients (17%) underwent bowel resection for mesenteric ischemia, compared with 3% in pre-COVID SVT ( p <0.001). Two patients died shortly after diagnosis (7%).

CONCLUSIONS

Although definite VITT was rare, in 72% of cases, no other cause for SVT could be identified following SARS-CoV-2 vaccination. These cases were different from patients with nonvaccine-related SVT, with lower incidence of prothrombotic conditions, higher rates of bowel ischemia, and poorer outcome. Although SVT after SARS-CoV-2 vaccination is rare in absolute terms, these data remain relevant considering ongoing revaccination programs.

A Case of Complete Resolution of Cauda Equina Syndrome Caused by Extensive Iliocaval Thrombosis: The Role of Thrombolysis and Venous Stents

PURPOSE

The cauda equina syndrome (CES) is a rare condition affecting less than 1 in 100,000 patients annually. Diagnosing CES is challenging because of its rare incidence, potentially subtle presentation, and various underlying etiologies. Vascular causes, such as inferior vena cava (IVC) thrombosis, are uncommon but should be considered, since timely recognition and treatment of deep vein thrombosis (DVT) as a cause of CES can avoid irreversible neurological damage.

CASE REPORT

A 30-year-old male presented with partial CES caused by nerve root compression due to venous congestion from an extensive iliocaval DVT. He completely recovered after thrombolysis and stenting of the IVC. His iliocaval tract remained patent until the last date of follow-up at 1 year without signs of post-thrombotic syndrome. Broad molecular, infectious, and hematological laboratory tests did not reveal any underlying disease for the thrombotic event, particularly no hereditary or acquired thrombophilia.

CONCLUSION

Timely recognition of venous thrombosis as a cause of CES is essential. This is the first case report of CES caused by an extensive iliocaval DVT successfully treated with thrombolysis and venous stenting with good resolution of DVT and CES.

CLINICAL IMPACT

This case-report describes a patient with cauda equina syndrome resulting from an extensive iliocaval deep vein thrombosis due to an underlying stenosis of the inferior vena cava. Thrombolysis and venous stenting succesfully restored venous patency and thereby relieved symptoms and signs of cauda equina syndrome, in addition to (long-term) therapeutic dose anticoagulation. It is important to timely recognize deep vein thrombosis as a cause of cauda equina syndrome and to consider endovenous treatment in a specialized center.

Stroke and Thromboembolism in Patients with Heart Failure and Sinus Rhythm: A Matter of Risk Stratification?

Patients with heart failure (HF) in sinus rhythm (SR) experience an increased incidence of thromboembolic events including stroke. Among patients with HF, high-quality evidence supports the use of oral anticoagulation when atrial fibrillation (AF) is present, but the benefit of anticoagulation in SR in absence of other known indications for anticoagulation is unclear. In four randomized controlled trials (RCTs), warfarin did not improve a composite of clinical outcomes compared with aspirin or placebo in patients with HF with reduced ejection fraction (HFrEF) and SR. A recent RCT assessed the efficacy of the direct oral anticoagulant rivaroxaban versus placebo in patients with HFrEF (including mildly reduced ejection fraction), SR and coronary artery disease. While rivaroxaban had a neutral effect on the primary composite outcome of MI, stroke, or all-cause mortality, exploratory analyses revealed a significant reduction in strokes. It is thus possible that a subgroup of patients with HFrEF who are at high risk of stroke may benefit from anticoagulation. The challenge is to adequately identify this subgroup and to balance the potential benefit of anticoagulation with the risk of major bleeding. There is also an unmet need for evidence around anticoagulation in HF with preserved ejection fraction (HFpEF) and SR. This review explores the current evidence around anticoagulation in patients with HF and SR, identifies challenges regarding outcome definitions and patient selection, and offers suggestions for future research.

Pregnancy outcomes in women with Budd-Chiari syndrome or portal vein thrombosis - a multicentre retrospective cohort study

Objective

To evaluate current practice and outcomes of pregnancy in women previously diagnosed with Budd–Chiari syndrome and/or portal vein thrombosis, with and without concomitant portal hypertension.

Design and setting

Multicentre retrospective cohort study between 2008 and 2021.

Population

Women who conceived in the predefined period after the diagnosis of Budd–Chiari syndrome and/or portal vein thrombosis.

Methods and main outcome measures

We collected data on diagnosis and clinical features. The primary outcomes were maternal mortality and live birth rate. Secondary outcomes included maternal, neonatal and obstetric complications.

Results

Forty‐five women (12 Budd–Chiari syndrome, 33 portal vein thrombosis; 76 pregnancies) were included. Underlying prothrombotic disorders were present in 23 of the 45 women (51%). Thirty‐eight women (84%) received low‐molecular‐weight heparin during pregnancy. Of 45 first pregnancies, 11 (24%) ended in pregnancy loss and 34 (76%) resulted in live birth of which 27 were at term (79% of live births and 60% of pregnancies). No maternal deaths were observed; one woman developed pulmonary embolism during pregnancy and two women (4%) had variceal bleeding requiring intervention.

Conclusions

The high number of term live births (79%) and lower than expected risk of pregnancy‐related maternal and neonatal morbidity in our cohort suggest that Budd–Chiari syndrome and/or portal vein thrombosis should not be considered as an absolute contraindication for pregnancy. Individualised, nuanced counselling and a multidisciplinary pregnancy surveillance approach are essential in this patient population.

Tweetable abstract

Budd–Chiari syndrome and/or portal vein thrombosis should not be considered as an absolute contraindication for pregnancy.

Budd–Chiari syndrome and/or portal vein thrombosis should not be considered as an absolute contraindication for pregnancy.

Linked article This article is commented on by YY Chung & MA Heneghan pp. 618 in this issue. To view this minicommentary visit https://doi.org/10.1111/1471-0528.17002.

Magnetic Resonance Thrombus Imaging to Differentiate Acute from Chronic Portal Vein Thrombosis

Introduction  Timely diagnosis and treatment of portal vein thrombosis (PVT) is crucial to prevent morbidity and mortality. However, current imaging tests cannot always accurately differentiate acute from chronic (nonocclusive) PVT. Magnetic resonance noncontrast thrombus imaging (MR-NCTI) has been shown to accurately differentiate acute from chronic venous thrombosis at other locations and may also be of value in the diagnostic management of PVT. This study describes the first phase of the Rhea study (NTR 7061). Our aim was to select and optimize MR-NCTI sequences that would be accurate for differentiation of acute from chronic PVT.

Study Design  The literature was searched for different MRI sequences for portal vein and acute thrombosis imaging. The most promising sequences were tested in a healthy volunteer followed by one patient with acute PVT and two patients with chronic PVT, all diagnosed on (repetitive) contrast-enhanced computed tomography (CT) venography to optimize the MR-NCTI sequences. All images were evaluated by an expert panel.

Results  Several MR-NCTI sequences were identified and tested. Differentiation of acute from chronic PVT was achieved with 3D T1 TFE (three-dimensional T1 turbo field echo) and 3D T1 Dixon FFE (three-dimensional T1 fast field echo) sequences with best image quality. The expert panel was able to confirm the diagnosis of acute PVT on the combined two MR-NCTI sequences and to exclude acute PVT in the two patients with chronic PVT.

Conclusion  Using 3D T1 TFE and 3D T1 Dixon FFE sequences, we were able to distinguish acute from chronic PVT. This clinical relevant finding will be elucidated in clinical studies to establish their test performance.

The prevention and management of asparaginase-related venous thromboembolism in adults: Guidance from the SSC on Hemostasis and Malignancy of the ISTH

Venous thromboembolism is a common complication of asparaginase-based chemotherapy regimens for the treatment of acute lymphoblastic leukemia. Thrombosis associated with asparaginase administration poses a number of specific and often clinically challenging management decisions. This review provides guidance on the prevention and treatment of thrombosis associated with asparaginase in adults including discussions on antithrombin repletion, pharmacologic thromboprophylaxis, cerebral venous thrombosis, and therapeutic anticoagulation.

Venous thromboembolism in a large cohort of children with acute lymphoblastic leukemia: Risk factors and effect on prognosis

BACKGROUND

Venous thromboembolism (VTE) is relatively common in children with acute lymphoblastic leukemia (ALL). Thrombotic risk factors in ALL are asparaginase and steroids. However, within the ALL populations treated on the same regimen, it is less clear which other risk factors play a role. Furthermore, few data are available on the effect of VTE on ALL outcomes.

METHODS

In 778 children (1-18 years) with newly diagnosed precursor-B-lineage or T-lineage ALL, treated in the Dutch Childhood Oncology Group (DCOG) ALL-10 protocol in the Netherlands (October 2004 to April 2013), we conducted a nested case control study with 59 VTE cases and 118 controls to identify risk factors for VTE.

RESULTS

Fifty-nine of 778 ALL patients developed VTE (7.6%), with cerebral venous sinus thrombosis (CVST) in 26 of 59 patients (44.1%). VTE occurred during induction treatment in 59.3% (n = 35) and in 40.7% (n = 24) during medium risk intensification. Conditional multivariable logistic regression analysis showed that age and ALL subtype were significantly associated with VTE (age ≥7 years: OR 2.72, 95% CI 1.33-5.57; ALL subtype T-ALL: OR 2.95, 95% CI 1.02-8.57). A multivariable Cox model showed no association between the occurrence of VTE and event free survival. In CVST patients, permanent disability was present in 34.6%.

CONCLUSION

Within this large pediatric ALL cohort, we demonstrated a high morbidity in CVST patients. Age ≥7 years at diagnosis and T-ALL subtype were the main risk factors for VTE, and should be considered in preventive strategies.

New oral anticoagulants for stroke prevention in atrial fibrillation: impact of study design, double counting and unexpected findings on interpretation of study results and conclusions

Four recently introduced new oral anticoagulants (dabigatran, rivaroxaban, apixaban and edoxaban) have been shown to be at least as efficacious and safe as warfarin for stroke prevention in patients with atrial fibrillation in their respective trials. The first three have been approved, while edoxaban is awaiting regulatory approval. Several guidelines have endorsed the approved new oral anticoagulants over warfarin because of their favourable risk-benefit ratio, low propensity for food and drug interactions, and lack of requirement for routine coagulation monitoring. In this invited review, we summarise the results of the four studies and discuss widely held conclusions. We take a step further and discuss how differences in study design, analysis plan, and unexpected events affect the interpretation of the study results. Finally, we take our re-interpretation of study results and discuss how they might impact clinical practice and anticoagulant choice for patients.

Venous thromboembolism in adults treated for acute lymphoblastic leukaemia: Effect of fresh frozen plasma supplementation

Treatment of acute lymphoblastic leukaemia (ALL) is frequently complicated by venous thromboembolism (VTE). The efficacy and optimal approach of VTE prevention are unclear, particularly in adult patients. We assessed the effect of thromboprophylaxis on symptomatic VTE incidence in cycle 1 of ALL treatment in adult patients. Secondly, we explored potential etiologic factors for VTE and the clinical impact of VTE on ALL outcome. We retrospectively assessed symptomatic VTE incidence and use of thromboprophylaxis in 240 adults treated for newly diagnosed ALL in the Dutch-Belgian HOVON-37 multicentre study (1999–2005). Potential etiologic factors were explored by analysis of patient and disease characteristics, impact of VTE on ALL outcome by analysis of complete remission and overall survival rates. Symptomatic VTE was observed in 24 of 240 patients (10%). Thromboprophylaxis differed by centre (prophylactic fresh frozen plasma (FFP) supplementation or no thromboprophylaxis) and was applied only during L-asparaginase in cycle 1. VTE incidence was significantly lower with FFP supplementation than without FFP (6% vs. 19%; adjusted odds ratio [OR] 0.28; 95% confidence interval [CI] 0.10–0.73). FFP did not influence antithrombin or fibrinogen plasma levels. Patients with VTE in cycle 1 had a significantly poorer complete remission rate (adjusted OR 0.18; 95% CI 0.07–0.50), particularly patients with cerebral venous thrombosis (adjusted OR 0.17; 95% CI 0.04–0.65). Our study suggests that prophylactic FFP supplementation effectively reduces symptomatic VTE incidence during ALL treatment in adults. This should be confirmed in a randomised controlled trial.

TropicALL study: Thromboprophylaxis in Children treated for Acute Lymphoblastic Leukemia with Low-molecular-weight heparin: a multicenter randomized controlled trial

Background

Venous thromboembolism (VTE) is a common and severe complication during treatment of acute lymphoblastic leukemia (ALL). An important cause is the intensive use of asparaginase. Prospective cohort studies in which prophylactic low-molecular-weight heparin (LMWH) was used to prevent VTE showed lower VTE risk than in historic control cohorts, with a negligible bleeding risk. However, the efficacy of thromboprophylaxis with LMWH during ALL treatment has never been investigated in a randomized design. Here, we present the protocol of a randomized controlled trial in which the efficacy and safety of thromboprophylaxis with high prophylactic dose LMWH versus no thromboprophylaxis will be assessed in children treated for primary ALL with asparaginase.

Methods/Design

Thromboprophylaxis in Children treated for Acute Lymphoblastic Leukemia with Low-molecular-weight heparin (TropicALL) is a multicenter, randomized controlled open-label trial conducted in the Netherlands. Patients between 1 and 19 years of age with primary ALL, who are treated within the Dutch Childhood Oncology Group (DCOG) ALL-11 or 12 study will be randomized to thromboprophylaxis with LMWH once daily, (dose of 85 IU/kg (intervention arm A)), or to no thromboprophylaxis (arm B, standard of care) during asparaginase courses of ALL treatment. Primary efficacy endpoint is symptomatic objectified VTE during ALL treatment; secondary efficacy endpoints are overall survival and the composite of symptomatic and asymptomatic objectified VTE. Primary safety endpoints are major bleeding, clinically relevant non-major bleeding and minor bleeding. A total of 324 patients will be included to obtain a relative risk reduction of 75% with a power of 80%, using a two-sided test with significance level α = 0.05.

Discussion

This trial will be the first to assess efficacy and safety of thromboprophylaxis with LMWH during asparaginase treatment for ALL in children in a randomized design.

Trail registration

Nederlands Trial Register NTR4707. Registered 30 July 2014.

Effects of dabigatran according to age in atrial fibrillation

OBJECTIVE

The prevalence of atrial fibrillation (AF) and the risk of stroke and bleeding vary according to age. To estimate effects of dabigatran, compared with warfarin, on stroke, bleeding and mortality in patients with AF in the Randomized Evaluation of Long-Term Anticoagulant Therapy (RE-LY) trial according to age, we analysed treatment effects using age as a continuous variable and using age categories.

METHODS

RE-LY included 10 855 (59.9%) patients aged <75 years, 4231 patients (23.4%) aged 75-79 years, 2305 (12.7%) aged 80-84 years and 722 (4.0%) aged ≥85 years at baseline.

RESULTS

Benefits of dabigatran versus warfarin regarding stroke (HR range 0.63 (95% CI 0.46 to 0.86) to 0.70 (0.31 to 1.57) for dabigatran 150 mg twice daily), HR range 0.52 (0.21 to 1.29) to 1.08 (0.73 to 1.60) for dabigatran 110 mg twice daily) and intracranial bleeding were maintained across all age groups (interaction p values all not significant). There was a highly significant interaction (p value interaction <0.001) between age and treatment for extracranial major bleeding, with lower rates with both doses of dabigatran compared with warfarin in younger patients (HR 0.78 (0.62 to 0.97) for 150 mg twice daily, HR 0.72 (0.57 to 0.90) for 110 mg twice daily) but similar (HR 1.50 (1.03 to 2.18) for 110 mg twice daily) or higher rates (HR 1.68 (1.18 to 2.41) for 150 mg twice daily) in older patients (≥80 years).

CONCLUSION

Effects of dabigatran compared with warfarin on stroke prevention and intracranial bleeding are consistent across all age groups. Effects of dabigatran on extracranial major bleeding are age dependent, supporting selection of dabigatran 110 mg twice daily for elderly patients (age ≥80 years).

TRIAL REGISTRATION NUMBER

Clinical trial registration number: https://clinicaltrials.gov NCT00262600.

Benefits and challenges of going abroad for research or clinical training

Research or clinical experience abroad is often encouraged for early career professionals to enhance their future career prospects. If resources are available to facilitate this, we believe that a fellowship abroad should definitely be considered. It can be a great asset, but also an exciting and scary experience at the same time. We, Nicoletta and Mandy, medical doctors in Italy and the Netherlands, respectively, have been fortunate enough to gain abroad experience: Nicoletta in Birmingham, United Kingdom, for 12 months, doing a clinical research fellowship in the field of anticoagulation and atrial fibrillation, working with Prof. Gregory Lip, and Mandy in Hamilton, ON, Canada, for 13 months, undertaking a clinical research fellowship in the field of anticoagulation, stroke and atrial fibrillation, with Dr John Eikelboom, Prof. Jack Hirsh, Prof. Jeff Weitz and, Prof. Stuart Connolly. As we have both experienced the benefits but also the challenges resulting from these encounters, we hope that this forum piece will provide other early career professionals with helpful suggestions and, above all, fill them with excitement about an international training opportunity.

Early career professionals: the mission of a task force

Early career researchers and clinicians face unique challenges in comparison with more senior colleagues, for instance connecting with expert leaders outside of their own institution to enhance their expertise. As the largest international thrombosis and hemostasis professional society, the ISTH can play a central role in supporting the development of early career professionals. The ISTH Early Career Task Force was formed to improve support for, and encourage collaboration between early career thrombosis and hemostasis researchers and clinicians. These activities include (1) maintaining an online forum for early career ISTH members to connect, promote clinical, research, funding and educational activities, and to generate a sense of community; (2) broaden ISTH's reach with early career professionals in the developing world through promotion of the Reach-the-World fellowships and translating ISTH websites into six languages; (3) encourage early career engagement with ISTH activities, such as guidelines and guidance document processing and online webinar series; and (4) establishing this early career forum series in this journal. The JTH Forum series will highlight the early career perspective on a wide range of issues relevant to this group, and all ISTH early career members are encouraged to contribute.

Clinical Course of Cerebral Venous Thrombosis in Adult Acute Lymphoblastic Leukemia

BACKGROUND

Venous thromboembolism (VTE) is a frequent complication in patients with acute lymphoblastic leukemia (ALL). A significant proportion of patients develop cerebral venous thrombosis (CVT).

METHODS

To investigate risk factors for and the clinical course of CVT in ALL patients, we describe all cases of CVT which occurred in a well-defined cohort of 240 adults, treated for newly diagnosed ALL in the HOVON (Dutch-Belgian Hemato-Oncology Cooperative Group)-37 study. We conducted a nested case-control study to explore the relevance of early symptoms and risk factors for CVT in ALL patients.

RESULTS

Nine of 240 patients developed CVT (4%). CVT occurred during or shortly after L-asparaginase therapy (in 8 cases) and shortly after intrathecal methotrexate injections (in all cases) during cycle I of remission induction treatment. CVT was associated with prior headache and seizures. In 5 of 9 patients with CVT, headache before the diagnosis of CVT occurred within 3 days after lumbar puncture and initially had a postural character.

CONCLUSIONS

CVT is relatively common in adult ALL patients. Our data suggest that CVT in adult ALL patients results from the additive effects of multiple risk factors, with a particular role for asparaginase and the effects of lumbar punctures for intrathecal therapy.

Risk of ischaemic stroke according to pattern of atrial fibrillation: analysis of 6563 aspirin-treated patients in ACTIVE-A and AVERROES

AIMS

The pattern of atrial fibrillation (AF) occurrence-paroxysmal, persistent, or permanent-is associated with progressive stages of atrial dysfunction and structural changes and may therefore be associated with progressively higher stroke risk. However, previous studies have not consistently shown AF pattern to predict stroke but have been hampered by methodological shortcomings of low power, variable event ascertainment, and variable anticoagulant use.

METHODS AND RESULTS

We analysed the rates of stroke and systemic embolism in 6563 aspirin-treated patients with AF from the ACTIVE-A/AVERROES databases. There was thorough searching for events and adjudication. Multivariable analyses were performed with the adjustment for known risk factors for stroke. Mean age of patients with paroxysmal, persistent, and permanent AF was 69.0 ± 9.9, 68.6 ± 10.2, and 71.9 ± 9.8 years (P < 0.001). The CHA2DS2-VASc score was similar in patients with paroxysmal and persistent AF (3.1 ± 1.4), but was higher in patients with permanent AF (3.6 ± 1.5, P < 0.001). Yearly ischaemic stroke rates were 2.1, 3.0, and 4.2% for paroxysmal, persistent, and permanent AF, respectively, with adjusted hazard ratio of 1.83 (P < 0.001) for permanent vs. paroxysmal and 1.44 (P = 0.02) for persistent vs. paroxysmal. Multivariable analysis identified age ≥ 75 year, sex, history of stroke or TIA, and AF pattern as independent predictors of stroke, with AF pattern being the second strongest predictor after prior stroke or TIA.

CONCLUSION

In a large population of non-anticoagulated AF patients, pattern of AF was a strong independent predictor of stroke risk and may be helpful to assess the risk/benefit for anticoagulant therapy, especially in lower risk patients.

Cerebral venous thrombosis and thrombophilia: a systematic review and meta-analysis

Cerebral venous thrombosis (CVT) is a rare manifestation of venous thromboembolism (VTE) and stroke. The aim of our systematic review was to provide an updated summary of the strength of association between CVT and thrombophilia and to explore the relevance of thrombophilia for recurrence of CVT or other VTE, or other outcome variables. MEDLINE (via PubMed), EMBASE (via Ovid), and CENTRAL were systematically searched, including references of retrieved articles. Cohort studies of ≥ 40 patients and case-control studies comparing the prevalence of thrombophilia in patients with CVT and unrelated controls were eligible. Two reviewers independently selected studies, assessed quality, and extracted data. A meta-analysis was performed for high quality case-control studies with unselected cases and healthy controls. Odds ratios with 95% confidence intervals were calculated and pooled. We included 23 cohort studies and 33 case-control studies. A significant association was demonstrated between CVT and all inherited thrombophilic factors, as well as increased levels of homocysteine. Inconclusive results were found on the relevance of thrombophilia for recurrent CVT or other VTE. Although there is a strong association between CVT and thrombophilia, the clinical relevance of thrombophilia testing in patients with CVT seems limited, similarly to other forms of VTE.

Cancer and venous thrombosis: current comprehensions and future perspectives

Venous thromboembolism (VTE) is a common complication in all types of cancer and adversely impacts cancer prognosis. Randomized controlled trials with primary thromboprophylaxis in cancer patients generally show effective VTE relative risk reductions of up to 60%. However, absolute risks of VTE were fairly low. Thromboprophylaxis should therefore only be recommended to cancer patients at highest risk of VTE, who may benefit most from prophylaxis. Predictive risk models to identify patients at a high risk of VTE are promising, however additional validation is required. An increasing proportion of cancer-associated VTE is formed by incidental VTE, with similar risk factors and clinical consequences. Randomized trials are not yet available, but it seems reasonable to treat incidental VTE similarly to symptomatic VTE. In a substantial proportion of patients with unprovoked VTE without known cancer at the time of VTE diagnosis, concomitant or occult cancer is identified. Studies have investigated the value of extensive screening over routine examinations alone for occult cancer. Although extensive screening may be able to identify more occult cancers, its clinical benefit over routine screening has not been demonstrated.

Circulating Nucleosomes and Neutrophil Activation as Risk Factors for Deep Vein Thrombosis

Objective—

The formation of neutrophil extracellular traps and the exposure of nucleosomes on these neutrophil extracellular traps contribute to coagulation activation and the propagation of deep vein thrombosis (DVT) in animal models. However, no data are available on the role of neutrophil extracellular traps or nucleosomes in patients with thrombosis.

Methods and Results—

We conducted a case–control study, in which levels of circulating nucleosomes and neutrophil elastase–α1-antitrypsin complexes were assessed in plasma from 150 patients with objectified symptomatic DVT (cases) and compared with 195 patients with a clinical suspicion of DVT but in whom DVT was excluded (controls). We explored the association between both nucleosomes and elastase–α1-antitrypsin complexes, and the presence of DVT by calculating the odds ratio with corresponding 95% CIs. Elevated levels of both circulating nucleosomes and elastase–α1-antitrypsin complexes were associated with a 3-fold risk of DVT, and the associations remained similar after adjustment for potential confounders (malignancy, smoking, recent immobilization, recent hospitalization). The risk increased with higher nucleosome and elastase–α1-antitrypsin complex levels, suggesting a dose-dependent relationship among circulating nucleosomes, activated neutrophils, and DVT.

Conclusion—

Our study suggests an association among circulating nucleosomes, activated neutrophils, and presence of DVT in humans, which might have implications for treatment and prevention.

Relevance of the JAK2V617F mutation in patients with deep vein thrombosis of the leg

Venous thromboembolism (VTE) can be the first presenting symptom in myeloproliferative neoplasms (MPN). Studies have demonstrated a high prevalence of the JAK2V617F mutation in patients with splanchnic vein thrombosis. Fewer studies have been done in patients with thrombosis outside the splanchnic area, showing a lower prevalence although the clinical relevance of the mutation in these patients, e.g., progression to overt MPN, remains unknown. The objective of this study was to determine the effect size of JAK2V617F in prospectively collected DNA samples of patients objectively diagnosed with deep vein thrombosis (DVT) of the leg and controls without DVT, with follow-up on JAK2V617F-positive patients to assess clinical relevance. Presence of JAK2V617F was determined in DNA samples from 187 patients with DVT and 201 controls, using quantitative RT-PCR. Hematological parameters were also analyzed. All initially JAK2V617F-positive patients were reassessed. Of 187 patients with DVT, 178 were analyzed for JAK2V617F, and in four (2.3%; 95% CI 0.1–4.4), JAK2V617F was present. Of 201 controls, 198 were analyzed; one was JAK2V617F positive (0.5%; 95% CI −0.5–1.5, OR 4.5; 95% CI 0.5–40.9). None had MPN features, nor upon reassessment after a median follow-up of 68.5 months. Four JAK2V617F-positive patients with DVT and one control without DVT did not develop overt MPN after a median follow-up of nearly 6 years. Thus, in patients with non-splanchnic venous thrombosis, JAK2V617F appears not to be clinically relevant.

The success of a weekly medical quiz. Test-based medical education

BACKGROUND

Clinical images and tests are considered useful tools to enhance the memorisation of facts and information in medical education. Therefore, we initiated a weekly medical quiz for our department of Internal Medicine.

METHODS

Every week, a new case on a single slide with relevant information and a representative image, is sent by e-mail to staff, residents and others. All are requested ona voluntary basis to e-mail the presumed diagnosis within one week.

RESULTS

After two years, 100 cases were presented to 452 registered participants. On average, only 33 of 452 (range 14 to 59) participants (7.3%; 95% CI 4.9 to 9.7) responded per case. Most presumed diagnoses were submitted on the same day the case was sent (OR 0.81; 95% CI 0.69 to 0.94; p<0.01). Cases with a high response rate were associated with relatively more correct answers than cases with a low response rate. In addition, it was striking that participants in some subspecialities, particularly specialists in infectious diseases, were much more likely to respond to cases in their own subspecialty.

CONCLUSION

Our experience with a weekly medical quiz demonstrates rather low response rates. This could be due to time restraints, but could also be due to the fact that doctors do not like to be wrong, and are afraid to fail among their peers. Hence, although images and tests may be helpful learning tools, the success and contribution of such clinical-based quizzes to medical education are difficult to determine.