Blood pressure control halves second ischemic stroke risk

by Bruce Sylvester – Following a first ischemic stroke, patients who keep their blood pressure well controlled appear to halve their risk of a second stroke, researchers reported on March 27, 2014 in the American Heart Association journal Stroke.

“It’s not enough to control blood pressure some of the time. Averages do not take into account variability in blood pressure readings from one check to the next,” said Amytis Towfighi, M.D., lead author and assistant professor of neurology at the Keck School of Medicine at the University of Southern California in Los Angeles, Calif. “Fluctuations in blood pressure may be associated with greater cardiovascular risk.”

The investigators analyzed retrospectively data from the Vitamin Intervention for Stroke Prevention (VISP) trial, which enrolled 3,680 ischemic stroke patients ages 35 and older from 1996-2003. VISP trial subjects came from the United States, Canada and Scotland.

All subjects had been evaluated for blood pressure levels at baseline, at one month, at six months and at six month intervals thereafter, up to 24 months.

The investigators adjusted the VISP data for age, sex and history of stroke, heart disease and other factors. They deemed blood pressure as under controlled when measured at 140 mmHg over 90 mmHg, or lower.

They found that less than 30 percent of the subjects achieved consistent blood pressure control for over 75 percent the 12-month study.

Subjects with elevated systolic blood pressure at baseline (over 153 mm Hg) who kept their blood pressure under control for more than 75 percent of the study period achieved  a 54 percent rate reduction in incidence of second stroke,  compared with those who achieved control less than 25 percent of the time.

With the low percentage of subjects in the trial controlling their blood pressure between clinic visits, “you can only imagine how poor blood pressure control is outside of the clinical trial setting,” Dr. Towfighi said. She noted that, after a first ischemic stroke, instead of just measuring blood pressure at clinical visits, it should done more often, possibly using technology at home and transmitting the data for evaluation.