Mean arterial blood pressure may be a barometer for poor neurologic outcomes in patients with acute ischemic stroke who undergo endovascular therapy.
Mads Rasmussen, MD
Results from an analysis of individual patient data from 3 randomized clinical trials revealed that mean arterial blood pressure (MABP) <70 mm Hg for more than 10 minutes and >90 mm Hg for more than 45 minutes is associated with higher rates of poor neurologic outcomes following endovascular therapy (EVT) in patients with acute ischemic stroke (AIS).
The study evaluated 365 patients with AIS (mean age, 71.4 years; 44.6% women; median National Institutes of Health Stroke Scale score, 17) who were enrolled in the SIESTA, ANSTROKE, and GOLIATH trials between April 2014 and February 2017. Each trial randomized patients to either general anesthesia (GA) or procedural sedation (PS) for the EVT procedure. During the ANSTROKE and SIESTA trials, investigators assessed functional outcome as a primary outcome, whereas GOLIATH assessed infarct growth.
Noninvasive blood pressure measurements during the SIESTA and ANSTROKE trials were performed every 5 minutes during the EVT procedure compared to the GOLIATH trial, which recorded invasive blood pressure variables every minute during the first 5 minutes, followed by every 5 minutes throughout the procedure.
Using the modified Rankin Score (mRS), patients were evaluated on neurologic outcomes 90 days post-EVT procedure. Previous study data was used to define hemodynamic exposure variables that were associated with poor outcomes. These variables included baseline MABP, systolic blood pressure (SBP), procedure MABP and SBP, 20% drop in MABP and SBP during EVT procedure, lowest and highest MABP and SBP during EVT procedure, and any recording of SBP less than 140 mm Hg during the procedure. Other variables included vasopressor treatment during procedure and blood pressure variability (change in MABP) calculated as the magnitude of the difference between baseline MABP and the mean of all MABP values measured during the procedure.
Of the 365 patients assessed, 182 (49.9%) were randomized to GA and 183 (50.1%) to PS. Investigators observed 8065 blood pressure measurements at 5-minute intervals, with 70 of them imputed.
Higher mRS scores were associated with a cumulative period of at least 10 minutes with <70 mm Hg MABP (adjusted OR, 1.51; 95% CI, 1.02-2.22) and a continuous episode of >20 minutes with <70 mm Hg MABP (adjusted OR, 2.30; 95% CI, 1.11-4.75). Additionally, patients who experienced a period of >45 minutes with >90 mm Hg MABP (adjusted OR, 1.49; 95% CI, 1.11-2.02) and a continuous episode of >115 minutes with >90 mm Hg MABP (adjusted OR, 1.89; 95% CI, 1.01-3.54) were more likely to experience an increase in 90-day mRS scores.
Investigators reported a 30% increase in odds of worse outcomes on the mRS at 90 days for every 10 minutes of cumulated time with MABP <70 mm Hg (adjusted OR, 1.30; 95% CI, 1.03-1.65; P=.03). As for the upper thresholds, an 8% increase in odds of worse outcomes on the mRS at 90 days was recorded for every 10 minutes of cumulated time with MABP >90 mm Hg.
“General anesthesia is often associated with hypotension whereas procedural sedation is typically associated with more stable hemodynamics. Recent data from our group indicate that general anesthesia is associated with improved functional outcome compared to conscious sedation. The use of strict blood pressure protocols may partly explain these findings,” study author Mads Rasmussen, MD, PhD, department of anesthesia, Aarhus University Hospital, in Denmark, told NeurologyLive. “Thus, it still needs to be established whether the influence of anesthesia method on outcome is specifically related to anesthetic strategy (general anesthesia vs procedural sedation/local anesthesia only) or strict attention to hemodynamic management.”
Rasmussen, M, Schonenberger S, Henden PL, et al. Blood pressure thresholds and neurologic outcomes after endovascular therapy for acute ischemic stroke: an analysis of individual patient data from 3 randomized clinical trials. JAMA Neurol. Published online January 27, 2020. doi:10.1001/jamaneurol.2019.4838.