The three cases (one of which was fatal) occurred in two women and one man in their 30s or 40s and involved blockages of the carotid and middle cerebral artery. Two of the three patients also had venous thrombosis involving the portal and cerebral venous system. All three also had extremely low platelet counts, confirmed antibodies to platelet factor 4, and raised D-dimer levels, all characteristic of the vaccine-induced immune thrombotic thrombocytopenia (VITT) reaction associated with the AstraZeneca vaccine.
They are described in detail in a letter published online on May 25 in the Journal of Neurology, Neurosurgery & Psychiatry
“These are [the] first detailed reports of arterial stroke believed to be caused by VITT after the AstraZeneca COVID vaccine, although stroke has been mentioned previously in the VITT data,” said senior author David Werring, PhD, FRCP.
“VITT has more commonly presented as CVST [Cerebral venous sinus thrombosis] which is stroke caused by a venous thrombosis; these cases are showing that it can also cause stroke caused by an arterial thrombosis,” explained Dr. Werring, professor of clinical neurology at the Stroke Research Centre, University College London.
“In patients who present with ischemic stroke, especially younger patients, and who have had the AstraZeneca vaccine within the past month, clinicians need to consider VITT as a possible cause, as there is a specific treatment needed for this syndrome,” he said.
Young patients presenting with ischemic stroke after receiving the AstraZeneca vaccine should urgently be evaluated for VITT with laboratory tests, including platelet count, D-dimers, fibrinogen, and anti-PF4 antibodies, the authors wrote, and then managed by a multidisciplinary team, including hematology, neurology, stroke, neurosurgery, and neuroradiology, for rapid access to treatments including intravenous immune globulin, methylprednisolone, plasmapheresis, and nonheparin anticoagulants such as fondaparinux, argatroban, or direct oral anticoagulants.
Dr. Werring noted that these reports do not add anything to the overall risk/benefit of the vaccine, as they are only describing three cases. “While VITT is very serious, the benefit of the vaccine still outweighs its risks,” he said. “Around 40% of patients hospitalized with COVID-19 experience some sort of thrombosis and about 1.5% have an ischemic stroke. Whereas latest figures from the U.K. estimate the incidence of VITT with the AstraZeneca vaccine of 1 in 50,000 to 1 in 100,000.
“Our report doesn’t suggest that VITT is more common than these latest figures estimate, but we are just drawing attention to an alternative presentation,” he added.
Three cases
The first patient in the current case series, a woman in her 30s, experienced an intermittent headache on the right side and around her eyes 6 days after the vaccine. Five days later, she awoke feeling drowsy and with weakness to her left face, arm, and leg.
Imaging revealed a blocked right middle cerebral artery with brain infarction and clots in the right portal vein. She underwent brain surgery to reduce the pressure in her skull, plasma removal and replacement, and received the anticoagulant fondaparinux, but she still unfortunately died.
The second patient, a woman in her late 30s, presented with headache, confusion, weakness in her left arm, and loss of vision on the left side 12 days after having received the vaccine. Imaging showed occlusion of both carotid arteries, as well as pulmonary embolism and a left cerebral venous sinus thrombosis.
Her platelet count increased following plasma removal and replacement and intravenous corticosteroids, and her condition improved after fondaparinux treatment.
The third patient, a man in his early 40s, presented 3 weeks after receiving his vaccination with problems speaking. Imaging showed a clot in the left middle cerebral artery, but there was no evidence of clots in the cerebral venous sinuses. He received a platelet and plasma transfusion, and fondaparinux, and remains stable.