Average Real Variability of Diastolic Blood Pressure During Acute Phase Could Independently Predict 3-month Functional Outcome for Ischemic Stroke

Abstract

Background and purpose-Blood pressure variability has a significant effect on stroke. There were controversial reports about its relationship with short term functional outcome remains controversial for ischemic stroke or transient ischemic attack (TIA). There were limited studies about its long-term effect. Our aim was to elucidate the effect of BPV on a 3-month functional outcome in patients with acute ischemic stroke or TIA. Methods—In this prospective observational study, a consecutive series of 400 patients were enrolled with acute ischemic stroke or TIA within 7 days. All patients were referred and monitored for BP at 2-hour intervals in the first 24 hours. Afterward, the BP was recorded every four hours up to the 7th day, with 1-hour deviation the daytime and 2 hours at night. All BP results were recorded into an electronic medical record (EMR) system. Average real variability (ARV) was used to analyze the blood pressure variability (BPV). All patients were followed up as planned for 90 days. The primary outcome was evaluated by the modified Rankin Scale (mRS); an unfavorable outcome was mRS≥2. For comparison, patients were respectively divided into two groups based on systolic blood pressure ARV (SBP ARV) or diastolic blood pressure ARV (DBP ARV). A multivariate logistic regression model was used to estimate the effect of between ARV BPV on functional outcomes. Results-Among the 400 patients, 46 (11.4%) had an unfavorable outcome (mRS>2) at 90 days. Their mean 24h DBP ARV was significantly higher than others (10.42±3.63 vs. 9.83±4.27 mm Hg; p=0.03). The high 24hDBPARV was defined above the median of 7.75 mmHg, which was statistically associated with an unfavorable outcome (64.7% vs. 35.3%; P=0.004). Further stepwise logistic regression analysis indicated that 24h high DBPARV was the independent predictor of an unfavorable outcome (adjusted OR 2.44%, 95% confidence interval: 1.24-4.74, P<0.01). Conclusions—High DBPARV during the acute phase is an independent and significant predictor of 90-day functional outcome for ischemic stroke or TIA.