Reducing the global burden of cerebral venous thrombosis: An international research agenda

BACKGROUND

Due to the rarity of cerebral venous thrombosis (CVT), performing high-quality scientific research in this field is challenging. Providing answers to unresolved research questions will improve prevention, diagnosis, and treatment, and ultimately translate to a better outcome of patients with CVT. We present an international research agenda, in which the most important research questions in the field of CVT are prioritized.

AIMS

This research agenda has three distinct goals: (1) to provide inspiration and focus to research on CVT for the coming years, (2) to reinforce international collaboration, and (3) to facilitate the acquisition of research funding.

SUMMARY OF REVIEW

This international research agenda is the result of a research summit organized by the International Cerebral Venous Thrombosis Consortium in Amsterdam, the Netherlands, in June 2023. The summit brought together 45 participants from 15 countries including clinical researchers from various disciplines, patients who previously suffered from CVT, and delegates from industry and non-profit funding organizations. The research agenda is categorized into six pre-specified themes: (1) epidemiology and clinical features, (2) life after CVT, (3) neuroimaging and diagnosis, (4) pathophysiology, (5) medical treatment, and (6) endovascular treatment. For each theme, we present two to four research questions, followed by a brief substantiation per question. The research questions were prioritized by the participants of the summit through consensus discussion.

CONCLUSIONS

This international research agenda provides an overview of the most burning research questions on CVT. Answering these questions will advance our understanding and management of CVT, which will ultimately lead to improved outcomes for CVT patients worldwide.

Characteristics and outcomes of cerebral venous thrombosis associated with COVID-19

INTRODUCTION

Previous reports and meta-analyses derived from small case series reported a mortality rate of up to 40% in patients with coronavirus disease 2019 associated cerebral venous thrombosis (COVID-CVT). We assessed the clinical characteristics and outcomes in an international cohort of patients with COVID-CVT.

PATIENTS AND METHODS

This was a registry study of consecutive COVID-CVT patients diagnosed between March 2020 and March 2023. Data collected by the International Cerebral Venous Thrombosis Consortium from patients with CVT diagnosed between 2017 and 2018 served as a comparison. Outcome analyses were adjusted for age and sex.

RESULTS

We included 70 patients with COVID-CVT from 23 hospitals in 15 countries and 206 controls from 14 hospitals in 13 countries. The proportion of women was smaller in the COVID-CVT group (50% vs 68%, p < 0.01). A higher proportion of COVID-CVT patients presented with altered mental state (44% vs 25%, p < 0.01), the median thrombus load was higher in COVID-CVT patients (3 [IQR 2-4] vs 2 [1-3], p < 0.01) and the length of hospital stay was longer compared to controls (11 days [IQR 7-20] vs 8 [4-15], p = 0.02). In-hospital mortality did not differ (5/67 [7%, 95% CI 3-16] vs 7/206 [3%, 2-7], aOR 2.6 [95% CI 0.7-9]), nor did the frequency of functional independence after 6 months (modified Rankin Scale 0-2; 45/58 [78%, 95% CI 65-86] vs 161/185 [87%, 81-91], aOR 0.5 [95% CI 0.2-1.02]).

CONCLUSION

In contrast to previous studies, the in-hospital mortality rate and functional outcomes during follow-up did not differ between COVID-CVT patients and the pre-COVID-19 controls.

Endovascular treatment of cerebral sinus thrombosis due to vaccine-induced immune thrombotic thrombocytopenia

INTRODUCTION

There is little data on the role of endovascular treatment (EVT) of cerebral venous sinus thrombosis (CVST) due to vaccine-induced immune thrombotic thrombocytopenia (VITT). Here, we describe clinical characteristics and outcomes of CVST-VITT patients who were treated with EVT.

PATIENTS AND METHODS

We report data from an international registry of patients who developed CVST within 28 days of SARS-CoV-2 vaccination, reported between 29 March 2021 and 6 March 2023. VITT was defined according to the Pavord criteria.

RESULTS

EVT was performed in 18/136 (13%) patients with CVST-VITT (92% aspiration and/or stent retrieval, 8% local thrombolysis). Most common indications were extensive thrombosis and clinical or radiological deterioration. Compared to non-EVT patients, those receiving EVT had a higher median thrombus load (4.5 vs 3). Following EVT, local blood flow was improved in 83% (10/12, 95% confidence interval [CI] 54-96). One (6%) asymptomatic sinus perforation occurred. Eight (44%) patients treated with EVT also underwent decompressive surgery. Mortality was 50% (9/18, 95% CI 29-71) and 88% (8/9, 95% CI 25-66) of surviving EVT patients achieved functional independence with a modified Rankin Scale score of 0-2 at follow-up. In multivariable analysis, EVT was not associated with increased mortality (adjusted odds ratio, 0.66, 95% CI 0.16-2.58).

DISCUSSION AND CONCLUSION

We describe the largest cohort of CVST-VITT patients receiving EVT. Half of the patients receiving EVT died during hospital admission, but most survivors achieved functional independence.

Sex differences in cerebral venous sinus thrombosis after adenoviral vaccination against COVID-19

INTRODUCTION

Cerebral venous sinus thrombosis associated with vaccine-induced immune thrombotic thrombocytopenia (CVST-VITT) is a severe disease with high mortality. There are few data on sex differences in CVST-VITT. The aim of our study was to investigate the differences in presentation, treatment, clinical course, complications, and outcome of CVST-VITT between women and men.

PATIENTS AND METHODS

We used data from an ongoing international registry on CVST-VITT. VITT was diagnosed according to the Pavord criteria. We compared the characteristics of CVST-VITT in women and men.

RESULTS

Of 133 patients with possible, probable, or definite CVST-VITT, 102 (77%) were women. Women were slightly younger [median age 42 (IQR 28-54) vs 45 (28-56)], presented more often with coma (26% vs 10%) and had a lower platelet count at presentation [median (IQR) 50x109/L (28-79) vs 68 (30-125)] than men. The nadir platelet count was lower in women [median (IQR) 34 (19-62) vs 53 (20-92)]. More women received endovascular treatment than men (15% vs 6%). Rates of treatment with intravenous immunoglobulins were similar (63% vs 66%), as were new venous thromboembolic events (14% vs 14%) and major bleeding complications (30% vs 20%). Rates of good functional outcome (modified Rankin Scale 0-2, 42% vs 45%) and in-hospital death (39% vs 41%) did not differ.

DISCUSSION AND CONCLUSIONS

Three quarters of CVST-VITT patients in this study were women. Women were more severely affected at presentation, but clinical course and outcome did not differ between women and men. VITT-specific treatments were overall similar, but more women received endovascular treatment.

Cerebral venous sinus thrombosis due to vaccine-induced immune thrombotic thrombocytopenia in middle-income countries

BACKGROUND

Adenovirus-based COVID-19 vaccines are extensively used in low- and middle-income countries (LMICs). Remarkably, cases of cerebral venous sinus thrombosis due to vaccine-induced immune thrombotic thrombocytopenia (CVST-VITT) have rarely been reported from LMICs.

AIMS

We studied the frequency, manifestations, treatment, and outcomes of CVST-VITT in LMICs.

METHODS

We report data from an international registry on CVST after COVID-19 vaccination. VITT was classified according to the Pavord criteria. We compared CVST-VITT cases from LMICs to cases from high-income countries (HICs).

RESULTS

Until August 2022, 228 CVST cases were reported, of which 63 were from LMICs (all middle-income countries [MICs]: Brazil, China, India, Iran, Mexico, Pakistan, Turkey). Of these 63, 32 (51%) met the VITT criteria, compared to 103 of 165 (62%) from HICs. Only 5 of the 32 (16%) CVST-VITT cases from MICs had definite VITT, mostly because anti-platelet factor 4 antibodies were often not tested. The median age was 26 (interquartile range [IQR] 20-37) versus 47 (IQR 32-58) years, and the proportion of women was 25 of 32 (78%) versus 77 of 103 (75%) in MICs versus HICs, respectively. Patients from MICs were diagnosed later than patients from HICs (1/32 [3%] vs. 65/103 [63%] diagnosed before May 2021). Clinical manifestations, including intracranial hemorrhage, were largely similar as was intravenous immunoglobulin use. In-hospital mortality was lower in MICs (7/31 [23%, 95% confidence interval (CI) 11-40]) than in HICs (44/102 [43%, 95% CI 34-53], p = 0.039).

CONCLUSIONS

The number of CVST-VITT cases reported from LMICs was small despite the widespread use of adenoviral vaccines. Clinical manifestations and treatment of CVST-VITT cases were largely similar in MICs and HICs, while mortality was lower in patients from MICs.

Direct oral anticoagulants for the treatment of cerebral venous thrombosis - a protocol of an international phase IV study

Introduction

Current guidelines recommend that patients with cerebral venous thrombosis (CVT) should be treated with vitamin K antagonists (VKAs) for 3-12 months. Direct oral anticoagulants (DOACs), however, are increasingly used in clinical practice. An exploratory randomized controlled trial including 120 patients with CVT suggested that the efficacy and safety profile of dabigatran (a DOAC) is similar to VKAs for the treatment of CVT, but large-scale prospective studies from a real-world setting are lacking.

Methods

DOAC-CVT is an international, prospective, observational cohort study comparing DOACs to VKAs for the prevention of recurrent venous thrombotic events after acute CVT. Patients are eligible if they are 18 years or older, have a radiologically confirmed CVT, and have started oral anticoagulant treatment (DOAC or VKA) within 30 days of CVT diagnosis. Patients with an absolute contra-indication for DOACs, such as pregnancy or severe renal insufficiency, are excluded from the study. We aim to recruit at least 500 patients within a three-year recruitment period. The primary endpoint is a composite of recurrent venous thrombosis and major bleeding at 6 months of follow-up. We will calculate an adjusted odds ratio for the primary endpoint using propensity score inverse probability treatment weighting.

Discussion

DOAC-CVT will provide real-world data on the comparative efficacy and safety of DOACs versus VKAs for the treatment of CVT.

Clinical trial registration

ClinicalTrials.gov, NCT04660747.

Decompressive surgery in cerebral venous sinus thrombosis due to vaccine-induced immune thrombotic thrombocytopenia

BACKGROUND AND PURPOSE

Cerebral venous sinus thrombosis due to vaccine-induced immune thrombotic thrombocytopenia (CVST-VITT) is an adverse drug reaction occurring after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. CVST-VITT patients often present with large intracerebral haemorrhages and a high proportion undergoes decompressive surgery. Clinical characteristics, therapeutic management and outcomes of CVST-VITT patients who underwent decompressive surgery are described and predictors of in-hospital mortality in these patients are explored.

METHODS

Data from an ongoing international registry of patients who developed CVST within 28 days of SARS-CoV-2 vaccination, reported between 29 March 2021 and 10 May 2022, were used. Definite, probable and possible VITT cases, as defined by Pavord et al. (N Engl J Med 2021; 385: 1680-1689), were included.

RESULTS

Decompressive surgery was performed in 34/128 (27%) patients with CVST-VITT. In-hospital mortality was 22/34 (65%) in the surgical and 27/94 (29%) in the non-surgical group (p < 0.001). In all surgical cases, the cause of death was brain herniation. The highest mortality rates were found amongst patients with preoperative coma (17/18, 94% vs. 4/14, 29% in the non-comatose; p < 0.001) and bilaterally absent pupillary reflexes (7/7, 100% vs. 6/9, 67% with unilaterally reactive pupil, and 4/11, 36% with bilaterally reactive pupils; p = 0.023). Postoperative imaging revealed worsening of index haemorrhagic lesion in 19 (70%) patients and new haemorrhagic lesions in 16 (59%) patients. At a median follow-up of 6 months, 8/10 of surgical CVST-VITT who survived admission were functionally independent.

CONCLUSIONS

Almost two-thirds of surgical CVST-VITT patients died during hospital admission. Preoperative coma and bilateral absence of pupillary responses were associated with higher mortality rates. Survivors often achieved functional independence.

Abstract 112: Cerebral Venous Sinus Thrombosis Due To Vaccine-induced Immune Thrombotic Thrombocytopenia In Middle-Income Countries

Introduction: Adenovirus-based COVID-19 vaccines are extensively used in low- and middle-income countries (LMICs). In India alone, 1.67 billion ChAdOx1 nCoV-19 vaccines have been administered by August 23, 2022. Surprisingly however, there are only few reports of cerebral venous sinus thrombosis due to vaccine-induced immune thrombotic thrombocytopenia (CVST-VITT) from LMICs. We aimed to gain insight into the frequency, manifestations, treatment, and outcomes of CVST-VITT in LMICs.

Methods: We report data from an international registry on CVST after COVID-19 vaccination. VITT was classified according to the Pavord criteria. We compared characteristics of CVST-VITT cases from LMICs to cases from high-income countries (HICs).

Results: By August 15, 2022, 228 CVST cases after vaccination were reported, of which 63 cases from LMICs (all middle-income countries [MICs]: Brazil, China, India, Iran, Mexico, Pakistan, and Turkiye). Of these, 32/63 (51%) met the criteria for definite, probable or possible VITT. Only 5/32 (16%) CVST-VITT cases from MICs had definite VITT, mostly because anti-PF4 antibodies were not tested in 21/32 (66%) cases. Patients from MICs were diagnosed in a later time period than patients from HICs (1/32 [3%] vs 65/103 [63%] cases diagnosed before May 2021, respectively). Median age was 26 (IQR 20-37) vs 47 (IQR 32-58) years, and proportion of women was 25/32 (78%) vs 77/103 (75%) in MICs vs HICs, respectively. Clinical manifestations, such as focal neurologic deficits, coma, seizures, and intracranial hemorrhages, were similar. Concomitant venous thromboembolism was less frequent in MICs (3/31 [10%] vs 26/97 [27%]). Median platelet count nadir was higher in the MICs than the HICs group (65 x10 9 /L [IQR 36-115] vs 33 x10 9 /L [IQR 18-55], p =0.001). Intravenous immunoglobulin use was similar (19/30 [63%] vs 63/99 [64%]). In-hospital mortality was lower in the MICs than the HICs group (7/32 [22%, 95%CI 11-39] vs 44/102 [43%, 95%CI 34-53], p =0.031).

Conclusions: The absolute number of CVST-VITT cases reported from LMICs was small despite the widespread use of adenoviral vaccines in these countries. Clinical manifestations and treatment of CVST-VITT cases were largely similar in MICs and HICs, while mortality was lower in patients from MICs.

Outcomes of Cerebral Venous Thrombosis due to Vaccine-Induced Immune Thrombotic Thrombocytopenia After the Acute Phase

BACKGROUND

Cerebral venous thrombosis (CVT) due to vaccine-induced immune thrombotic thrombocytopenia (VITT) is a severe condition, with high in-hospital mortality rates. Here, we report clinical outcomes of patients with CVT-VITT after SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) vaccination who survived initial hospitalization.

METHODS

We used data from an international registry of patients who developed CVT within 28 days of SARS-CoV-2 vaccination, collected until February 10, 2022. VITT diagnosis was classified based on the Pavord criteria. Outcomes were mortality, functional independence (modified Rankin Scale score 0-2), VITT relapse, new thrombosis, and bleeding events (all after discharge from initial hospitalization).

RESULTS

Of 107 CVT-VITT cases, 43 (40%) died during initial hospitalization. Of the remaining 64 patients, follow-up data were available for 60 (94%) patients (37 definite VITT, 9 probable VITT, and 14 possible VITT). Median age was 40 years and 45/60 (75%) patients were women. Median follow-up time was 150 days (interquartile range, 94-194). Two patients died during follow-up (3% [95% CI, 1%-11%). Functional independence was achieved by 53/60 (88% [95% CI, 78%-94%]) patients. No new venous or arterial thrombotic events were reported. One patient developed a major bleeding during follow-up (fatal intracerebral bleed).

CONCLUSIONS

In contrast to the high mortality of CVT-VITT in the acute phase, mortality among patients who survived the initial hospitalization was low, new thrombotic events did not occur, and bleeding events were rare. Approximately 9 out of 10 CVT-VITT patients who survived the acute phase were functionally independent at follow-up.

Management of Cerebral Venous Thrombosis Due to Adenoviral COVID-19 Vaccination

Objective

Cerebral venous thrombosis (CVT) caused by vaccine‐induced immune thrombotic thrombocytopenia (VITT) is a rare adverse effect of adenovirus‐based severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2) vaccines. In March 2021, after autoimmune pathogenesis of VITT was discovered, treatment recommendations were developed. These comprised immunomodulation, non‐heparin anticoagulants, and avoidance of platelet transfusion. The aim of this study was to evaluate adherence to these recommendations and its association with mortality.

Methods

We used data from an international prospective registry of patients with CVT after the adenovirus‐based SARS‐CoV‐2 vaccination. We analyzed possible, probable, or definite VITT‐CVT cases included until January 18, 2022. Immunomodulation entailed administration of intravenous immunoglobulins and/or plasmapheresis.

Results

Ninety‐nine patients with VITT‐CVT from 71 hospitals in 17 countries were analyzed. Five of 38 (13%), 11 of 24 (46%), and 28 of 37 (76%) of the patients diagnosed in March, April, and from May onward, respectively, were treated in‐line with VITT recommendations (p < 0.001). Overall, treatment according to recommendations had no statistically significant influence on mortality (14/44 [32%] vs 29/55 [52%], adjusted odds ratio [OR] = 0.43, 95% confidence interval [CI] = 0.16–1.19). However, patients who received immunomodulation had lower mortality (19/65 [29%] vs 24/34 [70%], adjusted OR = 0.19, 95% CI = 0.06–0.58). Treatment with non‐heparin anticoagulants instead of heparins was not associated with lower mortality (17/51 [33%] vs 13/35 [37%], adjusted OR = 0.70, 95% CI = 0.24–2.04). Mortality was also not significantly influenced by platelet transfusion (17/27 [63%] vs 26/72 [36%], adjusted OR = 2.19, 95% CI = 0.74–6.54).

Conclusions

In patients with VITT‐CVT, adherence to VITT treatment recommendations improved over time. Immunomodulation seems crucial for reducing mortality of VITT‐CVT. ANN NEUROL 2022;92:562–573

Cerebral venous thrombosis due to vaccine-induced immune thrombotic thrombocytopenia after a second ChAdOx1 nCoV-19 dose

Vaccine-induced immune thrombotic thrombocytopenia (VITT), a rare but life-threatening complication of adenoviral vaccination against COVID-19, has been reported almost entirely following the first dose. Krzywicka and colleagues report on 124 patients with VITT in a multinational registry diagnosed after dose 2; no specific events were observed after dose 1. These patients had early presentation, and two of the patients died.

Abstract 51: Age Stratified Risk Of Cerebral Venous Sinus Thrombosis After Sars-Cov-2 Vaccination

Introduction: Cerebral Venous Sinus Thrombosis (CVST) as a part of the thrombosis and thrombocytopenia syndrome is a rare adverse drug reaction of SARS-CoV-2 vaccination. The estimated background rate of CVST in adults is around 1 case per million per month, and CVST with thrombocytopenia accounts for 8% of all CVST. We assessed the age-stratified risk of CVST with and without thrombocytopenia after SARS-CoV-2 vaccination.

Methods: We estimated the absolute risk of any CVST, CVST with thrombocytopenia, and CVST without thrombocytopenia, within 28 days of first dose SARS-CoV-2 vaccination, using data from the European Medicines Agency’s EudraVigilance database (until 13 June 2021). As a denominator, we used data on vaccine delivery from 31 European countries. For 22.8 million adults from 25 countries we estimated the absolute risk of CVST after the first dose of ChAdOx1 nCov-19 per age category.

Results: The absolute risk of CVST within 28 days of first dose vaccination was 7.5 (95%CI 6.9-8.3), 0.7 (95%CI 0.2-2.4), 0.6 (95%CI 0.5-0.7) and 0.6 (95%CI 0.3-1.1) per million of first doses of ChAdOx1 nCov-19, Ad26.COV2.S, BNT162b2 and mRNA-1273, respectively. The absolute risk of CVST with thrombocytopenia within 28 days of first dose vaccination was 4.4 (95%CI 3.9-4.9), 0.7 (95%CI 0.2-2.4), 0.0 (95%CI 0.0-0.1) and 0.0 (95%CI 0.0-0.2) per million of first doses of ChAdOx1 nCov-19, Ad26.COV2.S, BNT162b2 and mRNA-1273, respectively. In recipients of ChAdOx1 nCov-19, the risk of CVST, both with and without thrombocytopenia, was the highest in the 18-24 years age group (7.3 per million, 95%CI 2.8-18.8 and 3.7, 95%CI 1.0-13.3, respectively). The risk of CVST with thrombocytopenia was the lowest in ChAdOx1 nCov-19 recipients ≥70 years (0.2, 95%CI 0.0-1.3). Age <60 compared to ≥60 was a predictor for CVST with thrombocytopenia (incidence rate ratio 5.79; 95%CI 2.98-11.24, p<0.001).

Discussion: The risk of CVST with thrombocytopenia within 28 days of first dose vaccination with ChAdOx1 nCov-19 was higher in younger age groups. The risk of CVST with thrombocytopenia was slightly increased in patients receiving Ad26.COV2.S, comparing with the estimated background risk. The risk of CVST with thrombocytopenia was not increased in recipients of mRNA vaccines for SARS-CoV-2.

Age-Stratified Risk of Cerebral Venous Sinus Thrombosis After SARS-CoV-2 Vaccination

BACKGROUND AND OBJECTIVES

Cerebral Venous Sinus Thrombosis (CVST) as a part of the thrombosis and thrombocytopenia syndrome is a rare adverse drug reaction of SARS-CoV-2 vaccination. Estimated background rate of CVST with thrombocytopenia is 0.1 per million per month. We assessed the age-stratified risk of CVST with and without thrombocytopenia after SARS-CoV-2 vaccination.

METHODS

We estimated the absolute risk of CVST with and without thrombocytopenia within 28 days of first dose of four SARS-CoV-2 vaccinations, using data from the European Medicines Agency's EudraVigilance database (until 13 June 2021). As a denominator, we used data on vaccine delivery from 31 European countries. For 22.8 million adults from 25 countries, we estimated the absolute risk of CVST after the first dose of ChAdOx1 nCov-19 per age category.

RESULTS

The absolute risk of CVST within 28 days of first dose vaccination was 7.5 (95%CI 6.9-8.3), 0.7 (95%CI 0.2-2.4), 0.6 (95%CI 0.5-0.7) and 0.6 (95%CI 0.3-1.1) per million of first doses of ChAdOx1 nCov-19, Ad26.COV2.S, BNT162b2 and mRNA-1273, respectively. The absolute risk of CVST with thrombocytopenia within 28 days of first dose vaccination was 4.4 (95%CI 3.9-4.9), 0.7 (95%CI 0.2-2.4), 0.0 (95%CI 0.0-0.1) and 0.0 (95%CI 0.0-0.2) per million of first doses of ChAdOx1 nCov-19, Ad26.COV2.S, BNT162b2 and mRNA-1273, respectively. In recipients of ChAdOx1 nCov-19, the absolute risk of CVST, both with and without thrombocytopenia, was the highest in the 18-24 years age group (7.3 per million, 95%CI 2.8-18.8 and 3.7 per million, 95%CI 1.0-13.3, respectively). The risk of CVST with thrombocytopenia in ChAdOx1 nCov-19 recipients was the lowest in the age group≥70 years (0.2, 95%CI 0.0-1.3). Age <60 compared to ≥60 was a predictor for CVST with thrombocytopenia (incidence rate ratio 5.79; 95%CI 2.98-11.24, p<0.001).

DISCUSSION

The risk of CVST with thrombocytopenia within 28 days of first dose vaccination with ChAdOx1 nCov-19 was higher in younger age groups. The risk of CVST with thrombocytopenia was slightly increased in patients receiving Ad26.COV2.S, compared with the estimated background risk. The risk of CVST with thrombocytopenia was not increased in recipients of SARS-CoV-2 mRNA vaccines.

Characteristics and Outcomes of Patients With Cerebral Venous Sinus Thrombosis in SARS-CoV-2 Vaccine-Induced Immune Thrombotic Thrombocytopenia

Importance

Thrombosis with thrombocytopenia syndrome (TTS) has been reported after vaccination with the SARS-CoV-2 vaccines ChAdOx1 nCov-19 (Oxford-AstraZeneca) and Ad26.COV2.S (Janssen/Johnson & Johnson).

Objective

To describe the clinical characteristics and outcome of patients with cerebral venous sinus thrombosis (CVST) after SARS-CoV-2 vaccination with and without TTS.

Design, Setting, and Participants

This cohort study used data from an international registry of consecutive patients with CVST within 28 days of SARS-CoV-2 vaccination included between March 29 and June 18, 2021, from 81 hospitals in 19 countries. For reference, data from patients with CVST between 2015 and 2018 were derived from an existing international registry. Clinical characteristics and mortality rate were described for adults with (1) CVST in the setting of SARS-CoV-2 vaccine-induced immune thrombotic thrombocytopenia, (2) CVST after SARS-CoV-2 vaccination not fulling criteria for TTS, and (3) CVST unrelated to SARS-CoV-2 vaccination.

Exposures

Patients were classified as having TTS if they had new-onset thrombocytopenia without recent exposure to heparin, in accordance with the Brighton Collaboration interim criteria.

Main Outcomes and Measures

Clinical characteristics and mortality rate.

Results

Of 116 patients with postvaccination CVST, 78 (67.2%) had TTS, of whom 76 had been vaccinated with ChAdOx1 nCov-19; 38 (32.8%) had no indication of TTS. The control group included 207 patients with CVST before the COVID-19 pandemic. A total of 63 of 78 (81%), 30 of 38 (79%), and 145 of 207 (70.0%) patients, respectively, were female, and the mean (SD) age was 45 (14), 55 (20), and 42 (16) years, respectively. Concomitant thromboembolism occurred in 25 of 70 patients (36%) in the TTS group, 2 of 35 (6%) in the no TTS group, and 10 of 206 (4.9%) in the control group, and in-hospital mortality rates were 47% (36 of 76; 95% CI, 37-58), 5% (2 of 37; 95% CI, 1-18), and 3.9% (8 of 207; 95% CI, 2.0-7.4), respectively. The mortality rate was 61% (14 of 23) among patients in the TTS group diagnosed before the condition garnered attention in the scientific community and 42% (22 of 53) among patients diagnosed later.

Conclusions and Relevance

In this cohort study of patients with CVST, a distinct clinical profile and high mortality rate was observed in patients meeting criteria for TTS after SARS-CoV-2 vaccination.

Declining mortality of cerebral venous sinus thrombosis with thrombocytopenia after SARS-CoV-2 vaccination

Background and purpose

High mortality rates have been reported in patients with cerebral venous sinus thrombosis (CVST) due to vaccine‐induced immune thrombotic thrombocytopenia (VITT) after vaccination with adenoviral vector SARS‐CoV‐2 vaccines. The aim of this study was to evaluate whether the mortality of patients with CVST‐VITT has decreased over time.

Methods

The EudraVigilance database of the European Medicines Agency was used to identify cases of CVST with concomitant thrombocytopenia occurring within 28 days of SARS‐CoV‐2 vaccination. Vaccines were grouped based on vaccine type (adenoviral or mRNA). Cases with CVST onset until 28 March were compared to cases after 28 March 2021, which was the day when the first scientific paper on VITT was published.

Results

In total, 270 cases of CVST with thrombocytopenia were identified, of which 266 (99%) occurred after adenoviral vector SARS‐CoV‐2 vaccination (ChAdOx1 nCoV‐19, n = 243; Ad26.COV2.S, n = 23). The reported mortality amongst adenoviral cases with onset up to 28 March 2021 was 47/99 (47%, 95% confidence interval 37%–58%) compared to 36/167 (22%, 95% confidence interval 16%–29%) in cases with onset after 28 March (p < 0.001). None of the four cases of CVST with thrombocytopenia occurring after mRNA vaccination died.

Conclusion

The reported mortality of CVST with thrombocytopenia after vaccination with adenoviral vector‐based SARS‐CoV‐2 vaccines has significantly decreased over time, which may indicate a beneficial effect of earlier recognition and/or improved treatment on outcome after VITT.