Lower stroke risk with lower blood pressure in hemodynamic cerebral ischemia

Abstract

Objective: To determine whether strict blood pressure (BP) control is the best medical management for patients with symptomatic carotid artery occlusion and hemodynamic cerebral ischemia.

Methods: In this prospective observational cohort study, we analyzed data from 91 participants in the nonsurgical group of the Carotid Occlusion Surgery Study (COSS) who had recent symptomatic internal carotid artery occlusion and hemodynamic cerebral ischemia manifested by ipsilateral increased oxygen extraction fraction. The target BP goal in COSS was ≤130/85 mm Hg. We compared the occurrence of ipsilateral ischemic stroke during follow-up in the 41 participants with mean BP ≤130/85 mm Hg to the remaining 50 with higher BP.

Results: Of 16 total ipsilateral ischemic strokes that occurred during follow-up, 3 occurred in the 41 participants with mean follow-up BP of ≤130/85 mm Hg, compared to 13 in the remaining 50 participants with mean follow-up BP >130/85 mm Hg (hazard ratio 3.742, 95% confidence interval 1.065-13.152, log-rank p = 0.027).

Conclusion: BPs ≤130/85 mm Hg were associated with lower subsequent stroke risk in these patients.

Classification of evidence: This study provides Class III evidence that control of hypertension ≤130/85 mm Hg is associated with a reduced risk of subsequent ipsilateral ischemic stroke in patients with recently symptomatic carotid occlusion and hemodynamic cerebral ischemia (increased oxygen extraction fraction).

Figure 1. Individual mean systolic and diastolic blood pressures for the 91 participants in the 2 Carotid Occlusion Surgery Study groups

Vertical bars depict the mean systolic (top of bar) and diastolic (bottom of bar) blood pressure of each participant in the study. Those who experienced an ipsilateral ischemic stroke within 2 years of randomization are shown in black. Three participants had mean systolic pressures below 130 mm Hg but diastolic pressures greater than 85 mm Hg. They are just to the right of the dotted vertical line.

Figure 2. Kaplan-Meier cumulative curves for occurrence of ipsilateral ischemic stroke

The number of participants who remained event-free and available for follow-up evaluation at each 90-day interval is shown for each group at the bottom of the graph. BP = blood pressure.

Figure 3. Rate of recurrent stroke within 2 years in the 5 blood pressure groups as defined in the PROFESS study

Kaplan-Meier estimates with vertical bars denoting standard error of the estimates.