Yasmin Aziz, MD
The search for the association between coronavirus and stroke began months ago in China. Since that time, various studies from around the world have sought to identify the incidence of vascular complications from the virus.
In this study from The University of Pennsylvania, the authors performed a retrospective observational study across three hospitals between March 15 and May 3 to evaluate the incidence and mechanism of stroke in patients with COVID-19. The authors first looked for hospital-admitted patients who tested positive for SARS-CoV2 and then filtered by patients who received head imaging (either CT or MRI). Mechanism was then determined by a stroke neurologist using TOAST classification criteria.
Of the 844 patients with coronavirus, 20 (2.5%) had ischemic stroke and 8 (0.9%) had hemorrhagic stroke. The majority of the patient population studied was older than 50 and had traditional vascular risk factors such as hypertension (95% ischemic, 75% hemorrhagic) and hyperlipidemia (80% ischemic, 65% hemorrhagic). Of note, 35% of patients with ischemic stroke had a history of prior stroke. In both groups, the majority of patients required mechanical ventilation (55% ischemic, 75% hemorrhagic), with half of the hemorrhagic strokes associated with use of ECMO. Cardioembolic etiology accounted for the majority of stroke (40%) followed by cryptogenic (35%) and other (20%). Interestingly, antiphospholipid antibodies were present in over 75% of patients tested. The average time from COVD-19 symptoms to stroke was 21 days.
The general incidence of stroke in patients with COVID-19 was 2.4% in this study, which is comparable to rates published in Wuhan and Northern Italy, but noticeably discrepant from a large observational study from New York City citing a 0.9% incidence. Factors affecting our understanding of regional incidence is dictated by resources in that particular area. Testing availability in the United States at the beginning stages of the pandemic was extremely limited, making it difficult to ascertain the rates of stroke in symptomatic, let alone asymptomatic, patients. Geographic trends in infection rates were also discrepant even within countries, with New York City hospitals bearing an enormous amount of cases early in the year. This likely contributed to higher death rates, as alluded to by the authors.
Future studies in this area should focus on hospital admission with asymptomatic vs symptomatic coronavirus infection in areas of robust testing. Upcoming studies should also stratify by race and antiphospholipid antibody positivity, in addition to traditional vascular risk factors, to better characterize trends seen in this study. Given the rates of intracranial hemorrhage noted in this study, risks regarding anticoagulation in these patients also deserve more study.