What Is the Ideal Blood Pressure Target for Secondary Stroke Prevention?

When the results of a randomized clinical trial assessing intensive blood pressure (BP) control for stroke prevention were pooled with the results of 3 prior trials, meta-analysis showed that intensive BP treatment targeting <130/80 mm Hg reduces secondary stroke recurrence by 22%, according to study results published in JAMA Neurology.

The Recurrent Stroke Prevention Clinical Outcome (RESPECT) Study tested whether intensive BP lowering treatment to a systolic (SBP) and diastolic blood pressure (SBP) <120/80 mm Hg would more effectively reduce stroke recurrence rates than standard BP-lowering regimens. Between October 20, 2010 and December 7, 2016, a total of 1280 participants with a history of stroke from 140 Japanese hospitals were enrolled and randomly assigned 1:1 to standard treatment (BP control to <140/90 mm Hg; n=640) or to intensive treatment (<120/80 mm Hg; n=640), given stepwise orally every 4 weeks for 24 weeks.

The study was registered as NCT01198496 with ClinicalTrials.gov, and the statistical significance threshold was set at 2-sided P <.05. Because 17 patients did not receive intervention, the final analysis included 1263 patients (standard treatment [n=630]; intensive treatment [n=633]). The primary endpoint was recurrent stroke, including ischemic stroke and intracerebral hemorrhage. The researchers also searched PubMed and Cochrane Central Library databases for studies comparing the effects of BP treatment using 2 different targets in patients with prior cerebrovascular disease.

Among the 1263 patients analyzed (69.4% men, mean age 67.2±8.8 years), 99.5% (1257/1263) completed a mean follow-up of 3.9±1.5 years. Mean baseline BP was 145.4±12.7/83.7±10.6 mm Hg, and throughout the follow-up period, the mean BP was 133.2/77.7 (95% CI, 132.5-133.8/77.1-78.4) mm Hg in the standard group and 126.7/74.4  (95% CI, 125.9-127.2/73.8-75) mm Hg in the intensive group, for a mean difference of 6.5/3.3 (95% CI, 5.7-7.5/2.5-4.2) mm Hg.

During the follow-up period, 91 participants experienced first recurrent strokes. The annualized rate of stroke recurrence was 2.26% in the standard treatment group compared with 1.65% in the intensive treatment group, for a nonsignificant rate of reduction (hazard ratio 0.73; 95% CI, 0.49-1.11; P =.15).

When these results were pooled with 3 prior relevant randomized controlled trials assessing BP control for secondary stroke prevention, the updated meta-analysis showed a risk ratio that favored intensive BP control (relative risk 0.78; 95% CI, 0.64-0.96; P =.02), with no evidence of heterogeneity (I²=0%).

Pooling the absolute risk difference found an estimated risk difference of −1.5% (95% CI, −2.6% to −0.4%), and the estimated number needed to treat to avoid stroke recurrence was 67 (95% CI, 39-250).

Study limitations included the unmasked assignment of treatment groups, no patients >85 years old, and no individual studies with statistically significant reductions in secondary stroke prevention.

Study investigators concluded that although the trial was limited by not having sufficient power to draw statistical significance for all strokes, combining the results with the 3 other trials “supports that the use of a BP target less than 130/80 mm Hg is likely to be beneficial in patients with a history of stroke.”

Disclosure: This clinical trial was supported by Bristol-Myers Squibb Company; Merck & Co., Inc.; OMRON Corporation; and Towa Pharmaceutical Co, Ltd.. Please see the original reference for a full list of authors’ disclosures.

Reference

Kitagawa K, Yamamoto Y, Arima H, et al; Recurrent Stroke Prevention Clinical Outcome (RESPECT) Study Group.. Effect of standard vs intensive blood pressure control on the risk of recurrent stroke: a randomized clinical trial and meta-analysis [published online July 29, 2019]. JAMA Neurol. doi:10.1001/jamaneurol.2019.2167