Blood pressure threshold violations in the first 24 hours after admission for acute stroke: frequency, timing, predictors, and impact on clinical outcome.

BACKGROUND AND PURPOSE Admission blood pressure (BP) and significant decreases in BP after acute stroke have been correlated with outcome. Few data are available on the impact of extreme values at any time point within the first 24 hours. METHODS BP was measured hourly for 24 hours in 325 consecutive patients with acute ischemic stroke. Predefined endpoints were systolic BP >or=200, diastolic BP >or=110, or systolic BP <100 mm Hg during the first 24 hours, and significant systolic BP decreases by >26 mm Hg within 4 hours after admission. Multiple logistic regression analysis identified independent predictors of each end point and determined the impact on dependency at 3 months defined as modified Rankin scale score >or=3. RESULTS Upper threshold violations occurred in 70% of cases during the admission process, and more frequently in patients arriving early after stroke; 30% of cases exhibited such values at a later time point. History of hypertension (P<0.01) and higher NIHSS on admission (P<0.05) were independent predictors. Systolic BP <100 mm Hg occurred at random and was associated with younger age (P<0.05). Night time admission was the strongest independent predictor of systolic BP decreases >26 mm Hg (P<0.0001). Diabetes, NIHSS on admission, and age were associated with adverse outcome at 3 months, whereas threshold violations and decreases were not. There was a trend for administration of antihypertensives being associated with poor outcome (P<0.1). CONCLUSIONS External stimuli, premorbid risk factors, diurnal BP variations, and disease-immanent mechanisms all influence the course of BP after acute stroke. Monitoring should precede any medical BP treatment.