Introduction
The coronavirus disease 2019 (COVID-19) pandemic caused by the new type of coronavirus 2 (SARS-CoV-2) was shown to affect both the respiratory tract and neurologic systems. The neurologic impairments that may occur as a result of the spread of the virus to the central nervous system through various mechanisms are headache, dizziness, impaired consciousness, seizures, encephalitis, cerebrovascular diseases, neuromuscular disorders, and peripheral nervous system involvement. Neurologic symptoms can occur in more than 50% of hospitalized patients (1).
Acute ischemic stroke (AIS) is a life-threatening complication of COVID-19. Information on the incidence of stroke, which is an important cause of morbidity and mortality, its association with COVID-19, and its course in infected patients in this pandemic period is increasing. Uncontrolled cytokine storm seen in severe disease can lead to multi-organ failure, and the activation of the microthrombotic pathway with destructive pathologic mechanisms mediated by the endothelial system can cause stroke (2).
When assessing the link between COVID-19 and ischemic stroke, AIS has been increasingly documented in younger patients with COVID-19 (3) or patients without cardiovascular risk factors and significant comorbidities (4). To date, the true incidence of AIS in patients with COVID-19 remains unclear, but in a study of 214 patients in Wuhan, the first epicenter of the pandemic, the incidence was 2.34% (5), it was 0.9% in a study in New York (6), and 1.2% in a more recent pooled analysis that evaluated 4466 patients (7).
It is known that in the pathogenesis of SARS-CoV2, the virus enters the cell by binding to the ACE-2 receptor. ACE-2 receptors, found in many tissues, are also present in endothelial cells. In the course of the disease, an increase in inflammatory markers, a deterioration in coagulation parameters such as elevation of D-dimer and thrombocytopenia, and an increase in blood pressure predispose to ischemic and hemorrhagic cerebrovascular events (8). It has been suggested that COVID-19 may induce a prothrombotic state accompanied by high fibrinogen and D-dimer levels (9). It has also been reported in various case series and reports that large vessel occlusion (LVO) is more common in patients with AIS and COVID-19 (3).
Given the rapidly increasing COVID-19 prevalence and its AIS complications globally, it is important to understand their relationship more deeply. The literature published to date has been limited to case reports, case series, and observational cohort studies. The number of studies including the effect of COVID-19 on mortality and prognosis in patients with AIS, and diagnostic and prognostic laboratory investigations are limited. In this study, it was aimed to compare the demographic, clinical, and stroke characteristics, neuroimaging findings, prognosis, and mortality of patients with AIS with and without COVID-19 admitted during the same period.