Initial emergency department blood pressure as predictor of survival after acute ischemic stroke

Objective: To evaluate the association of diastolic blood pressure (dBP), systolic blood pressure (sBP), and mean arterial pressure (MAP) in the emergency department (ED) with mortality within 90 days in patients with acute ischemic stroke (AIS). Methods: This observational study was conducted at an ED with an annual census of 70,000 visits, with approximately 500 for AIS. The cohort consisted of 357 patients who presented to the ED within 24 hours of stroke symptom onset. sBP and dBP were measured at triage by a nurse blinded to the study. The duration of follow-up was limited to the first 90 days following ED presentation. BP levels were categorized as low, normotensive, and high after examining scatter plots of a patient's risk of death adjusted for duration of follow-up vs dBP, sBP, and MAP. These BP categories were evaluated using indicator variables in Cox proportional hazards models, after adjusting for age, sex, and the National Institute of Health Stroke Scale (NIHSS) score. Results: Patients with low BP (dBP < 70, sBP < 155, or MAP < 100 mm Hg) were significantly more likely to die within 90 days than those with BP in the normotensive range (dBP 70 to 105, sBP 155 to 220, MAP 100 to 140 mm Hg). These associations were significant even after adjusting for age, gender, and NIHSS score. Conclusions: There appears to be an optimal acute BP range below which early mortality is greater following AIS, suggesting avoidance of hypotension in the first 24 hours.