Study Group
Data were collected in the setting of a prospective, hospital-based, multicentre study conducted in Lombardy, Northern Italy. Because of the spread of the epidemic, on March 8, 2020, the Lombardy regional government passed a deliberation to reduce to 10 the hospitals with catheterization facilities for the treatment of acute ischemic stroke acting as hubs, with the remaining hospitals acting as spokes, on the basis of geographic proximity. Since these 10 centers were designated hospitals for transfer of patients from the contiguous catchment area at the early stage of the outbreak, they included all patients who were hospitalized in Lombardy for acute ischemic stroke during the epidemic. The STROKOVID network is a joint initiative of these 10 hub centers, which is expected to provide comprehensive information on patients hospitalized for acute ischemic stroke in Lombardy during SARS-CoV-2 outbreak and to address clinical research questions. In the present retrospective analysis, we investigated the impact of infection on reperfusion therapies for acute brain ischemia and in-hospital patients outcome in a cohort of patients admitted between March 8 and April 30, 2020. Individual data from all patients who received reperfusion therapies during the study period were collected with a standardized form with predefined variables. Local study investigators completed the forms systematically using prospectively ascertained in-hospital ischemic stroke registries. Completed forms from all centers were compiled in the coordinating center Brescia, where the analysis of the pooled data was performed. The Institutional Ethical Standards Committee on human experimentation at each study center provided approval for the study.
Risk factor definition
Hypertension was defined as systolic blood pressure 140 mm Hg or higher and diastolic pressure 90 mm Hg or higher in 2 separate measurements after the acute phase or use of antihypertensive drugs before recruitment; diabetes, with a history of diabetes, use of a hypoglycemic agent or insulin, or fasting glucose level 126 mg/dL or higher; current smoking, including former smokers who had quit smoking for 2 years before the index event; hypercholesterolemia, with cholesterol serum levels 220 mg/dL or higher or use of cholesterol lowering drugs. Body mass index (BMI) was calculated as weight in kilograms divided by the square of the height in meters (kg/m2). All patients underwent continuous cardiac monitoring using standard bedside monitors immediately after SU admission. In those patients who had not received a diagnosis before the index stroke, atrial fibrillation (AF) was eventually diagnosed by a cardiologist based on the ECGs performed in the emergency room with patients in a supine position using standard, 10-second, 12-lead ECG devices, as well as on the ECG recordings performed during hospital stay. We also collected information on history of coronary ischemic heart disease (myocardial infarction, history of angina, or existence of multiple lesions on thallium heart isotope scan or evidence of coronary disease on coronary angiography), previous ischemic stroke (based on clinical history or medical records), and pre-stroke medications (in particular, warfarin, aspirin or other antiplatelet agents, antihypertensive agents, oral hypoglycemic agents or insulin, and statins).
Neurovascular assessment and procedures
Patients received an initial diagnostic evaluation and treatment based on established guidelines [3]. All patients were classified into etiologic subgroups according to the Trial of ORG 10172 in Acute Stroke Treatment criteria [4] by local investigators at each study center. Initial stroke severity was assessed by the National Institutes of Health Stroke Scale score [5]. Early ischemic changes were quantified using the Alberta Stroke Program Early CT Score (ASPECTS) [6,7] on baseline CT. We systematically assessed the following variables: modified Rankin Scale score [8] before stroke (pre-stroke mRS), blood pressure values on admission before any stroke therapy, time from stroke symptoms onset to hospital admission, time from stroke symptoms onset to baseline brain imaging, and, in patients who received endovascular recanalization therapy, time from stroke symptoms onset to treatment and time from femoral puncture to recanalization. When indicated, cerebral large-artery occlusion was confirmed by head and neck CT angiography. Patients who were deemed eligible, received intravenous thrombolysis or endovascular mechanical thrombectomy or a combined treatment with full-dose intravenous rtPA and ‘‘contemporary/as soon as possible’’ endovascular mechanical thrombectomy [3]. Any decision on the technique and the specific device for endovascular thrombectomy was left to the discretion of the neurointerventionalist in charge of the patient in each centre. For middle cerebral artery (MCA) occlusion, the collateral circulation was scored on a 0 – 3 points scale. A score of zero indicated absent collateral supply to the occluded MCA territory. A score of 1 indicated collateral supply filling ≤ 50% but > 0% of the occluded MCA territory. A score of 2 was given for collateral supply filling > 50% but < 100% of the occluded MCA territory. A score of 3 was given for 100% collateral supply of the occluded MCA territory [9]. After treatment, recanalization grade was assessed on digital subtraction angiography based on the Thrombolysis in Cerebral Infarction (TICI) scale, considering grades 2b and 3, as good recanalization [10]. Intracerebral haemorrhage was any intracerebral bleeding detected at follow up non-contrast CT performed during hospital stay. Symptomatic intracerebral hemorrhage (sICH) was defined according to the European Cooperative Acute Stroke Study III (ECASS III) criteria [11].
Laboratory procedures
Laboratory confirmation of SARS-CoV-2 infection was made by RT PCR procedure on throat-swab and nasopharyngeal specimens [12] in all patients admitted to the participating hospitals. In case of high clinical suspicion of SARS-CoV-2 infection and negative test results on two nasopharyngeal and oropharyngeal swabs performed at least 24 hours apart, testing of lower respiratory samples (bronchoalveolar lavage fluid obtained by bronchoscopy) was performed.
Statistical Analysis
We compared the characteristics of patients with positive SARSCoV-2 nucleic acid test (COVID-19) with those of patients with negative test result (non-COVID-19). For subgroup comparisons, we used the χ2 test or the Fisher exact test, and the Mann–Whitney U test, when appropriate. Results are given as odds ratio with 95% CI. p ≤ 0.05 on 2-sided test was considered significant. Data were analyzed using the SPSS (version 21.0) package (www.spss.com).