The Changing Effect of Blood Pressure on Stroke Outcomes Through Acute to Subacute Stage of Ischemic Stroke

Abstract

BackgroundThis study explored the associations of blood pressure (BP) with various stroke outcomes and investigated their changes by the elapsed time after stroke onset. MethodsPatients who arrived within 48 hours of stroke onset between April 2008 and September 2014 were consecutively enrolled. For 10 days of hospitalization, all measured systolic BP (SBP) was summarized into mean at acute (first 3 days) and subacute stage (afterward to 7 days) for each patient. Coprimary outcomes were unfavorable outcome (modified Rankin Scale >2) at discharge and time to composite cardiovascular event of stroke, myocardial infarction, and vascular death for 1-year follow-up. Adjusted odds ratios (AOR) through SBPmean in both acute and subacute stages were interpolated using restricted cubic spline technique and adopted logistic regression models with predetermined covariates. The adjusted hazard ratios for cardiovascular event by SBPmean in both stages were interpolated. ResultsThe study enrolled 3723 subjects (mean age, 66.7 ± 13.2 years old and median baseline National Institute of Health Stroke Scale score, 3). SBPmean in both stages showed linear trends for risks of unfavorable outcome, while the increase of AOR was observed explicitly in acute stage rather than subacute stage, especially in higher values. In contrast, SBPmean demonstrated the U-shaped associations with cardiovascular event in subacute stage rather than acute stage. ConclusionsIn ischemic stroke, association patterns of BP would be different depending on stroke outcomes. The risky interval of BP would be changed by the elapsed time after stroke onset.