Intensive Blood Pressure Control Reduces Risk of Recurrent Stroke

By Will Boggs MD

NEW YORK (Reuters Health) - Intensive blood pressure control to a target less than 120/80 mm Hg is associated with a small reduction in the risk of recurrent stroke, compared with standard blood pressure control to a target less than 140/90 mm Hg, researchers from Japan report.

"Intensive blood pressure (BP) control is shown to have clear benefit for secondary stroke prevention," Dr. Kazuo Kitagawa from Tokyo Women's Medical University, Tokyo, Japan told Reuters Health in an email. "Thus, please control BP to less than 130/80 mm Hg whenever patients tolerate BP reduction."

Intensive blood pressure control is associated with lower rates of major cardiovascular events, but it remains unclear whether intensive blood pressure control is more effective than standard blood pressure control for secondary stroke prevention.

Dr. Kitagawa and colleagues in the Recurrent Stroke Prevention Clinical Outcome (RESPECT) study group investigated whether intensive blood pressure control (<120/80 mm Hg) is more effective than standard blood pressure control (<140/90 mm Hg) for reducing the rate of stroke recurrence in their study of 1,263 patients with a history of stroke within the previous three years.

To achieve target blood pressures, patients received stepwise treatments orally every four weeks for 24 weeks' maximum during the titration.

The study was terminated before reaching the planned sample size of 2000 because of slow recruitment and cessation of funding, according to the July 29th JAMA Neurology online report.

The mean blood pressure at baseline was 145.4/83.6 mm Hg, which declined at one year of follow-up to 132.0/77.5 mm Hg in the standard target group and to 123.7/72.8 mm Hg in the intensive group.

Target blood pressure levels were achieved by 61.7% in the standard group but by only 32.0% in the intensive group.

The annualized rate of recurrent stroke was nominally lower in the intensive group (1.65%) than in the standard treatment group (2.26%), a difference that fell short of statistical significance (P=0.15).

In subgroup analyses, the rate of intracerebral hemorrhage was significantly lower in the intensive treatment group (0.04% per patient-year) than in the standard treatment group (0.46% per patient-year), but the rates of ischemic stroke did not differ between the groups.

When the researchers conducted an updated meta-analysis, adding their results to those from three prior trials, they found a 22% reduction in the risk of secondary stroke associated with intensive blood pressure lowering, which translated to an estimated risk difference of 1.5 percentage points and an estimated number needed to treat to avoid one recurrent stroke of 67, compared with standard blood pressure lowering.

In a meta-analysis performed for ischemic and hemorrhagic stroke separately, the risk reduction associated with intensive blood pressure control persisted only for hemorrhagic stroke and not for ischemic stroke.

"This finding will be incorporated in future practical guidelines about secondary stroke prevention," Dr. Kitagawa said. "More intensive BP lowering, such as less than 120/80 mm Hg, might be beneficial for patients with high risk of intracerebral hemorrhage."

Dr. Craig S. Anderson from The George Institute for Global Health, Sydney, New South Wales, Australia and Beijing, China, who wrote an editorial related to this report, told Reuters Health by email, "While the overall results of this study support meta-analyses of other clinical trials showing that lower levels of systolic blood pressure offer greater benefits in prevention of stroke, the most surprising aspect of the RESPECT study was the massive reduction in the prevention of stroke due to acute intracerebral hemorrhage, which provides strong support for aggressive blood pressure control in patients who have suffered an intracerebral hemorrhage in the first place."

He reiterated the "lower than expected blood pressure difference between randomized groups, and the higher than expected average level of systolic blood pressure in the intensive group. Thus, while the epidemiology and systematic reviews of clinical trials in patients adherent to therapy confirms benefits of low blood pressure, there are obvious practical challenges to ensure blood pressure can be effective lowered without causing side-effects and even harms to patients."

Dr. Anderson suggested that physicians "consider faster and more intensive blood pressure management in stroke patients, ideally with early combination forms of antihypertensive therapy."

Dr. Sun Kwon from University of Ulsan, Asan Medical Center, Seoul, Korea, whose recent study found that intensive blood pressure control may not be safe in subacute ischemic stroke, told Reuters Health by email, "BP control in the stroke population is not easy to generalize. Intensive BP control will be beneficial in some stroke populations, such as lacunar stroke or hemorrhagic stroke."

Dr. Anantha R. Vellipuram from Texas Tech University Health Sciences Center in El Paso, Texas, who recently reviewed lifestyle interventions to prevent cardiovascular events after stroke, told Reuters Health by email, "In spite of stepwise treatment protocols and follow-ups for subjects, only 32% in the intensive group were able to achieve the target BP levels at one year. This could be very challenging when translated to real world practice as it needs immense commitment from both the patient as well as health care provider in accomplishing such goals."

"Ideal management in such situations should be individualized," he said.

RESPECT was funded by Merck and Company Inc., Bristol-Myers Squibb, Towa Pharmaceutical Company Ltd., and Omron Corporation, which had no role in the design and conduct of the study. Five of the 24 authors of this report had various relationships with one or more of these companies.

SOURCE: https://bit.ly/2ODfexI and https://bit.ly/2OvrpfJ

JAMA Neurol 2019.

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