Mei Yan Ngun, MBBS
The battle against the COVID-19 pandemic continues worldwide. As our understanding of COVID-19 evolves, so does our understanding of its neurological complications. Available evidence shows COVID-19 induces a hypercoagulable state and increases risk of thrombosis, especially in severe disease.
Early data has suggested a higher rate of ischemic stroke in severe COVID-19 infection. Majidi et al. have reported on the clinical and paraclinical findings in emergent large vessel occlusion (ELVO) stroke during New York’s COVID-19 outbreak. This retrospective observational study included data from all patients presenting with an ELVO during the peak 3-week period of hospitalizations and deaths from COVID-19. Data was collected from eight New York hospitals from March 21 to April 12, 2020. Data regarding demographics, comorbidities, risk factors, clinical presentation, treatment received, clinical outcome, and COVID-19 disease status were collected.
Baseline characteristics, imaging findings, and laboratory values were compared between COVID-19 positive and COVID-19 negative ELVO patients during the study period. The total number of ELVO patients during the 3-week COVID-19 period were collected. Next, the total number of ELVO patients during consecutive 3-week periods from March 20, 2020 backwards to the entirety of 2019 were collected. The number of ELVOs during the COVID-19 period were compared to the 21 consecutive 3-week pre-COVID-19 periods in an exploratory analysis.
During this period, a little more than half (53%) of the 45 ELVO patients tested positive for COVID-19. COVID-19 infected patients were younger than patients without COVID-19 (mean age 59±13 versus 74±17, OR= 0.94; 95% CI 0.81–0.98, P=0.004). They were also more likely to be male (75% versus 43%, OR=3.99; 95% CI 1.12–14.17, P=0.032) and non-white (38% versus 8%, OR=0.15; 95% CI 0.04–0.81, P=0.027). Atrial fibrillation was less common in COVID-19 infected patients, but there was no significant difference in the number of patients without any vascular risk factors between the COVID-19-positive and COVID-19-negative groups. Interestingly, although the prevalence of known congestive heart failure was lower in the COVID-19 positive group, 3 out of 4 patients who had new onset reduced ejection fraction were COVID-19 positive. None of the COVID-19 positive patients had signs of vasculopathy on cerebral digital subtraction angiography or computed tomography angiography of head and neck.
Many (42%) of the COVID-19 patients with ELVO did not have typical COVID-19 symptoms on presentation, though most of the patients developed these symptoms while in hospital. Four COVID-19 patients remained asymptomatic aside from stroke.
The number of patients presenting with ELVO during the COVID-19 outbreak doubled when compared to the mean number of patients from 21 consecutive 3-week periods prior to the outbreak (45 patients versus average 21 patients; estimate: 0.78; 95% CI 0.47–1.08, P≤0.0001). Importantly, the rate of intravenous tissue plasminogen activator (IV-tPA) administration and endovascular thrombectomy during the COVID-19 outbreak was similar to the pre-COVID-19 period.
The pathophysiology of ischemic stroke in COVID-19 infection is still under investigation, but several theories have been suggested. COVID-19 infection can cause a hypercoagulable state in severe disease, cardiac injury resulting in cardioembolic events, and endothelial injury via direct viral invasion through angiotensin-converting enzyme 2. Direct viral invasion of the central nervous system by hematogenous or trans-synaptic neuronal route has also been proposed.
This study provides evidence of a possible association between COVID-19 and large vessel occlusion stroke. Even patients who present without typical symptoms of COVID-19 may develop ELVO.
Therefore, it may be prudent to maintain a high index of suspicion for COVID-19 infection in ELVO when the prevalence of this disease is high in the community. This may be especially important with younger, male patients who present with ELVO during an outbreak of COVID-19. Given the relatively small sample size of this study, further studies are needed to establish the incidence of ELVO in the COVID-19 population, as well as characteristics of COVID-19 disease that are correlated with ELVO stroke.
