To the Editor:Morbidity and mortality associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are extremely visible 1 ; however, the effect of the COVID-19 pandemic on the management of other pathologies requiring complex interventions and critical care resources-the bystander effect 2 -is not well described. This is certainly true of stroke patients whose clinical outcomes are a function of early presentation, timely diagnosis, emergent intervention, and critical care management. [3][4][5] With the arrival of COVID-19 cases in the month of March in the hotspot of Michigan, we describe the bystander effect of the COVID-19 pandemic on ischemic and hemorrhagic stroke. METHODSThis is a retrospective analysis of deidentified data submitted from 11 Comprehensive Stroke Centers (CSCs) and 1 Primary Stroke Center (PSC) in Michigan and northwest Ohio. The study was approved by the University Institutional Review Board. Patient consent was not required given the retrospective nature of the study. Using Poisson regression analysis, we calculated the incidence-rate ratios (IRRs) comparing the study period of March 2020 to each of the control periods (February 2020 and March 2019). Additionally, the unpaired t-test for continuous variables and the Chi-square test for categorical variables were used as appropriate.

We were able to identify the vasa nervorum along the outer aspect of the studied nerves using contrast-enhanced ultrasound.

Background: There is controversy regarding the optimal size of stent retriever for achieving timely recanalization in acute ischemic stroke patients. Objective: To determine the relationship between stent retriever diameter and procedure time, and rates of recanalization, and functional independence among acute ischemic stroke patients undergoing mechanical thrombectomy. Methods: We analyzed data from consecutive acute ischemic stroke patients treated with mechanical thrombectomy derived from a prospective database. Baseline demographic and clinical characteristics, NIHSS score on admission and discharge, intracranial hemorrhage occurrence, and mRS at discharge were analyzed. Thrombolysis In Cerebral Infarction (TICI) scale was used to grade pre and post procedure angiographic recanalization. Procedural time was defined by the time interval between microcatheter placement and recanalization. We compared the rates of thrombectomy attempts, complete recanalization (TICI grade of 3), and functional independence (defined by mRS 0-2) between patients treated with 6 mm and 3-4 mm diameter stent retrievers. Results: A total of 230 acute ischemic stroke patients (mean age 71.8 ±12.5; 46.6% women) were treated with stent retrievers. Thrombectomy was performed with a 6mm diameter stent retriever in 107 patients and 3 or 4 mm diameter stent retriever in 123 patients. There were no statistically significant differences in demographics or baseline characteristics, or admission NIHSS score between the two groups. There was a trend towards a fewer number of thrombectomy attempts required with a 6mm diameter stent retriever (p=0.06). There was a higher rate of complete recanalization in patients treated with 6mm diameter stent retriever compared with 3 or 4 mm diameter stent retriever (72% vs 57.7% p=0.02). There was no statistically significant difference in rates of functional independence between the two groups (24.3% vs 25.2% p=0.84) at discharge. Conclusion: Among acute ischemic stroke patients undergoing mechanical thrombectomy, use of a 6 mm diameter stent retriever was associated with a higher rate of complete recanalization and a lower number of thrombectomy attempts compared with 3-4 mm diameter stent retrievers.