Thrombus Distribution in Vaccine-induced Immune Thrombotic Thrombocytopenia after ChAdOx1 nCov-19 Vaccination.

Vaccination strategies have been at the forefront of controlling the COVID-19 pandemic. An association between vaccine-induced immune thrombotic thrombocytopenia (VITT) and one of these vaccines, the ChAdOx1 nCov-19 vaccine, is now recognized. The purpose of this study was to investigate the frequency and location of thrombosis in each vascular system using CT, MRI, and US to identify additional sites of thrombus in a United Kingdom-wide sample of patients with confirmed VITT. Thirty-two radiology centers identified through the national collaborative Radiology Academic Network for Trainees were invited from the United Kingdom; seven of these contributed to this study. All patients with confirmed VITT ¬between February 3 and May 12, 2021, who met the inclusion criteria were included. The location and extent of thrombi were evaluated using CT, MRI, and US. A total of 40 patients (median age, 41 years [IQR, 32-52]; 22 [55%] men) with confirmed vaccine-induced immune thrombotic thrombocytopenia after administration of their first ChAdOx1 nCov-19 vaccine were included. Thirty-two patients (80%) developed symptoms within the first 14 days, and eight (20%) developed symptoms within 14-28 days. Twenty-nine patients (72%) experienced neurologic symptoms and were confirmed to have cerebral venous sinus thrombosis, 12 (30%) had clinical deterioration and repeat imaging demonstrated extension of their primary thrombus, and eight (20%) died. Twenty-five of 30 patients (83%) who underwent additional imaging had occult thrombosis. In conclusion, patients with VITT are likely to have multiple sites of thrombosis, with the most frequent being cerebral venous sinus thrombosis in combination with pulmonary embolism and portomesenteric venous thrombosis. Whole-body imaging with contrast-enhanced CT can be used to identify occult thrombosis.

Cerebral venous sinus thrombosis after adenovirus-vectored COVID-19 vaccination: review of the neurological-neuroradiological procedure.

Cerebral venous and sinus thrombosis (CVST) after adenovirus-vectored COVID-19 ChAdOx1 nCov-19 (Oxford-AstraZeneca) and Ad26.COV2.S (Janssen/Johnson & Johnson) is a rare complication, occurring mainly in individuals under 60 years of age and more frequently in women. It manifests 4-24 days after vaccination. In most cases, antibodies against platelet factor-4/polyanion complexes play a pathogenic role, leading to thrombosis with thrombocytopenia syndrome (TTS) and sometimes a severe clinical or even fatal course. The leading symptom is headache, which usually increases in intensity over a few days. Seizures, visual disturbances, focal neurological symptoms, and signs of increased intracranial pressure are also possible. These symptoms may be combined with clinical signs of disseminated intravascular coagulation such as petechiae or gastrointestinal bleeding. If TTS-CVST is suspected, checking D-dimers, platelet count, and screening for heparin-induced thrombocytopenia (HIT-2) are diagnostically and therapeutically guiding. The imaging method of choice for diagnosis or exclusion of CVST is magnetic resonance imaging (MRI) combined with contrast-enhanced venous MR angiography (MRA). On T2*-weighted or susceptibility weighted MR sequences, the thrombus causes susceptibility artefacts (blooming), that allow for the detection even of isolated cortical vein thromboses. The diagnosis of TTS-CVST can usually be made reliably in synopsis with the clinical and laboratory findings. A close collaboration between neurologists and neuroradiologists is mandatory. TTS-CVST requires specific regimens of anticoagulation and immunomodulation therapy if thrombocytopenia and/or pathogenic antibodies to PF4/polyanion complexes are present. In this review article, the diagnostic and therapeutic steps in cases of suspected TTS associated CSVT are presented.

Imaging and Hematologic Findings in Thrombosis and Thrombocytopenia after ChAdOx1 nCoV-19 (AstraZeneca) Vaccination.

This case series reports six patients (four men and two women; median age, 38 years; interquartile range, 26-48 years) who presented with vaccine-induced thrombocytopenia and thrombosis beginning 3-26 days after receiving the first dose of the ChAdOx1 nCoV-19 (AstraZeneca) vaccine for COVID-19. The patients were admitted to a general hospital between 9 and 31 days after the first dose. All patients had strongly detected antiplatelet factor 4 antibodies and severe thrombosis. Laboratory features included thrombocytopenia and elevated d-dimer levels. Thrombotic events were predominantly venous; two patients had arterial or mixed arterial and venous thrombosis. All patients recovered after receiving intravenous immunoglobulin and nonheparin-based anticoagulation. © RSNA, 2021 An earlier incorrect version appeared online. This article was corrected on August 18, 2021.

Cerebral venous sinus thrombosis associated with vaccine-induced thrombotic thrombocytopenia.

Thrombosis-thrombocytopenia syndrome and cerebral venous sinus thrombosis have been rarely reported in patients who have received severe acute respiratory syndrome coronavirus 2 adenoviral vector vaccines. Awareness of this potential adverse effect, recognizing early clinical symptoms and subtle signs of cerebral venous sinus thrombosis on head computed tomography and brain magnetic resonance imaging, appropriate vascular imaging, and unique treatment for this condition is critical. This is a report of a case of vaccine-induced thrombotic thrombocytopenia and associated cerebral venous sinus thrombosis with emphasis on imaging and clinical course.