Abstract T MP75: Effect of Subacute BP Variability on Subsequent Vascular Events in Patients with Acute Ischemic Stroke

Objectives: We recently reported that blood pressure variability (BPV) during a subacute stage of ischemic stroke may affect functional outcome. This study aimed to test a hypothesis whether subacute BPV increases a risk of subsequent vascular events following acute ischemic stroke. Methods: From a prospective stroke registry database, consecutive ischemic stroke patients hospitalized within 48 h of onset were identified. Subacute BPV parameters were defined as maximum2-minimum, standard deviation (SD) and coefficient of variation (CV) of systolic BP (SBP) from 72 hours after onset to discharge. Primary outcome was a time to a subsequent vascular event (SVE), which was a composite of stroke, myocardial infarction and other vascular death. The BPV parameters were categorized into tertiles and dose-response relationships between BPV parameters and SVE were examined. The hazard ratios (HRs) of BPV parameters were estimated using Cox proportional hazard models with adjustments for predetermined confounders. Result: Of 3047 patients (mean age, 66.4 years and median NIHSS score, 3); BP was measured by median 46 times per person during the subacute stage (median 7 days). Median follow-up duration was 352 days (interquartile range, 112 to 389 days) and cumulative SVE rates were 7.0%. SVE rates differed by the tertiles of BPV parameters; SVE rates of lower, middle and upper thirds of maximum-minimum were 5.2%, 6.4% and 9.6%, those of SD were 5.4%, 8.5% and 7.9% and those of CV were 4.9%, 8.4% and 7.6%, respectively (P’s < 0.05 on log rank test). There were significant dose-response relationships of SVE with maximum-minimum and SD (P < 0.01 and 0.01), not with CV (P = 0.14) independent of mean SBP, age, sex, history of stroke, hypertension, diabetes mellitus, hyperlipidemia, atrial fibrillation and stroke subtypes. Adjusted HRs of one-SD of maximum-minimum, SD and CV of SBP were 1.24 (95% confidence interval, 1.09-1.40), 1.16 (1.01-1.32) and 1.15 (1.01-1.30), respectively. Conclusion: This study suggests that the increase of blood pressure variability at subacute stage of ischemic stroke may increase the risk of subsequent vascular events.