Effect of blood pressure on 3-month functional outcome in the subacute stage of ischemic stroke

Abstract

Objective: We aimed to study various measures of blood pressure (BP) in the subacute phase of ischemic stroke to determine whether any of them predicted clinical outcome.

Methods: In this retrospective observational study, a consecutive series of patients hospitalized for ischemic stroke within 48 hours of onset were enrolled. The subacute stage of stroke was defined as the time period from 72 hours of symptom onset to discharge or transfer. During this period, mean, maximum, maximum - minimum, SD, and coefficient of variation of systolic BP (SBP) and diastolic BP (DBP) were determined. A baseline severity-adjusted analysis was performed using each patient's 3-month modified Rankin Scale score as the primary outcome.

Results: Among a total of 2,271 patients, the median number of BP measurements was 34 per person and the median interval from onset to discharge was 8.7 days. Measures of variability of BP were associated with poor outcome. One SD increase of maximum - minimum (odds ratio [OR], 1.26; 95% confidence interval [CI], 1.12-1.42), SD (OR, 1.20; 95% CI, 1.07-1.34), or coefficient of variation (OR, 1.21; 95% CI, 1.09-1.35) for SBP, but not mean level of SBP (OR, 0.92; 95% CI, 0.79-1.07), was independently associated with poor outcome. Results were similar for DBP.

Conclusion: This study shows that variability of BP, but not average BP in the subacute stage of ischemic stroke, is associated with functional outcome at 3 months after stroke onset.

Figure. Proportion of 3-month poor outcome (dark bar) according to the quintiles of blood pressure parameters

(A) Systolic blood pressure (SBP)_mean, (B) SBP_maximum, (C) SBP_{maximum−minimum}, (D) SBP_SD, (E) SBP_CV, (F) diastolic blood pressure (DBP)_mean, (G) DBP_maximum, (H) DBP_minimum, (I) DBP_{maximum−minimum}, (J) DBP_SD, and (K) DBP_CV. p Values are for χ² *linear trend test or for †likelihood ratio test for trend adjusted by age, sex, history of stroke, history of hypertension, baseline National Institutes of Health Stroke Scale score, stroke subtype, diabetes mellitus, atrial fibrillation, SBP_mean at acute stage, and time from onset to discharge. CV = coefficient of variation.