Retrospective review COVID-19 vaccine induced thrombotic thrombocytopenia and cerebral venous thrombosis-what can we learn from the immune response.

Introduction: Cerebral Venous Thrombosis (CVT), prior to the COVID pandemic, was rare representing 0.5 of all strokes, with the diagnosis made by MRI or CT venography. COVID-19 patients compared to general populations have a 30-60 times greater risk of CVT compared to non-affected populations, and up to a third of severe COVID patients may have thrombotic complications. Currently, vaccines are the best way to prevent severe COVID-19. In February 2021, reports of CVT and Vaccine-induced immune thrombotic thrombocytopenia (VITT) related to adenovirus viral vector vaccines including the Oxford-AstraZeneca vaccine (AZD1222 (ChAdOx1)) and Johnson & Johnson COVID-19 vaccine (JNJ-78436735 (Ad26.COV2·S)), were noted, with a 1/583,000 incidence from Johnson and Johnson vaccine in the United States. This study retrospectively analyzed CVT and cross-sectional venography at an Eastern Medical Center from 2018 to 2021, and presents radiographic examples of CVT and what is learned from the immune response.

Methods: After IRB approval, a retrospective review of cross-sectional CTV and MRVs from January 1st 2018 to April 30th 2021, at a single health system was performed. Indications, vaccine status, patient age, sex, and positive finding incidence were specifically assessed during March and April for each year. A multivariable-adjusted trends analysis using Poisson regression estimated venogram frequencies and multivariable logistic regression compared sex, age, indications and vaccination status.

Results And Discussion: From January 1, 2018 to April 30, 2021, (Fig. 1), a total of n = 2206 in patient and emergency room cross-sectional venograms were obtained, with 322 CTVs and 1884 MRVs. In 2018, 2019, 2020, respective totals of cross-sectional venograms were 568, 657, 660, compared to 321 cross-sectional venograms in the first four months of 2021. CTV in 2018, 2019, 2020, respective totals were 51, 86, 97, MRV totals were 517, 571, 563, compared to the 2021 first four month totals of 88 CTVs and 233 MRVs. March, April 2018, 2019, 2020, CTVs respectively were 6, 17, 11, compared to the 2021 first four months of 59 CTVs, comprising 63% of the total 93 CTVs, respective MRVs were 79, 97, 52, compared to 143 MRVs in the first four months of 2021 for 39% of the total 371 MRVs. In March, April 2020 during the pandemic onset, cross-sectional imaging at the East Coast Medical Center decreased, as priorities were on maintaining patient ventilation, high level of care and limiting spread of disease. In March/April 2021, reports of VITT and CVT likely contributed to increased CTVs and MRVs, of 39.65% [1.20-1.63] increase (P < 0.001) from prior. In March, April 2021 of 202 venograms obtained, 158 (78.2.%) were unvaccinated patients, 16 positive for CVT (10.1%), 44 were on vaccinated patients (21.7%), 8 specifically ordered with vaccination as a clinical indication, 2 positive for CVT (4.5%), (odds ratio = 0.52 [0.12-2.38], p = 0.200).

Conclusion: CTV prior to the COVID pandemic, was rare, responsible for 0.5 of all strokes, at the onset of the pandemic in the East Coast, overall cross-sectional imaging volumes declined due to maintaining ventilation, high levels of care and limiting disease spread, although COVID-19 patients have a 30-60 times greater risk of CVT compared to the general population, and vaccination is currently the best option to mitigate severe disease. In early 2021, reports of adenoviral vector COVID vaccines causing CTV and VITT, led to at 39.65% increase in cross-sectional venography, however, in this study unvaccinated patients in 2021 had higher incidence of CVT (10.1%), compared to the vaccinated patients (4.5%). Clinicians should be aware that VITT CVT may present with a headache 5-30 days post-vaccination with thrombosis best diagnosed on CTV or MRV. If thrombosis is present with thrombocytopenia, platelets <150 × 10, elevated D-Dimer >4000 FEU, and positive anti-PF4 ELISA assay, the diagnosis is definitive. VITT CVT resembles spontaneous autoimmune heparin induced thrombocytopenia (HIT), and is postulated to occur from platelet factor 4 (PF4) binding to vaccine adenoviral vectors forming a novel antigen, anti-PF4 memory B-cells and anti-PF4 (VITT) antibodies..