Difference In Subacute Blood Pressure Between Office And Ambulatory Values Predicts Functional Outcome After Ischemic Stroke

Objective: Acute hypertensive response after ischemic stroke is a self-limiting phenomenon and is associated with functional outcome. Excessive BP fluctuations may reflect increased sympathetic nervous system activity, which can impair the brain repair after stroke. Whether individual BP variation, based on difference between single office and full ambulatory 24-hour BP measurements, have a distinct long-term significance for stroke outcome remains unknown. We tested the hypothesis that subacute BP difference (BPD) [(office BP – mean daytime BP)/mean daytime BP] is independently associated with stroke outcome. Design and method: In a prospective study, we included 132 patients (age 62.9 + /- 12.9, NIH Stroke Scale score (NIHSS) 7.0 + /- 6.2) with acute ischemic stroke. Office (Omron) and Ambulatory BP monitoring (SpaceLabs) was performed on day 7 after stroke onset. The daytime period was defined as the interval from 6 AM to 10 PM. The relationship between these measures (adjusted for age, sex, admission neurological deficit as assessed by NIHSS score, baseline glucose level, and HR) and the 90-day poor outcome (death or dependency, modified Rankin Scale > 2) was studied using a multivariate logistic regression. Results: At 3 months, 28 (21.2%) patients had moderate to severe functional impairment after stroke. BPD given as a percentage was significantly higher in patients with poor outcome (14.2 + /−20.5 vs 2.0 + /−13.5; p < 0.001). In univariate analysis, high BPD (OR = 1.56; 95% CI, 1.19–2.05; p = 0.001) was significantly associated with poor stroke outcome. Age, sex, baseline neurological deficit and glucose level, thrombolytic treatment and subacute systolic BP and heart rate measured at day 7 also predicted stroke functional outcome. In multivariate analysis, the predictive value of BPD remained significant (OR = 2.01; 95% CI, 1.15–3.53; p = 0.01) after adjustment for covariates. Office BP also slightly predicted stroke outcome (OR = 1.02; 95% CI, 1.00–1.04; p = 0.04). By contrast, ambulatory BP levels had no significant predictive value after adjustment.Conclusions: Difference in BP between subacute office and ambulatory values is an independent predictor of functional outcome in patients after ischemic stroke. Both office and ambulatory BP reading are needed to evaluate stroke prognosis accurately.