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Controlling BP reduces chance of second stroke
Contact: Heather Woolwine
March 28, 2014
CHARLESTON – Stroke survivors who consistently control their blood pressure may reduce the likelihood of a second stroke by more than half, according to new research in the American Heart Association journal Stroke.
Study authors, including Bruce Ovbiagele, M.D., MUSC Department of Neurology and Neurosurgery chairman and professor, found that among individuals with elevated blood pressure at baseline (systolic blood pressure over 153 mm Hg), second stroke risk was reduced by 54 percent among participants who kept their blood pressure under control more than 75 percent of the time, compared with those who kept it under control less than 25 percent of the time. Unfortunately, fewer than 30 percent of participants maintained consistent blood pressure control more than 75 percent of the time.
“Over time, a patient may average a blood pressure that falls within normal, but this study suggests that providers and patients should also factor in the proportion of time (or visits) in which that patient’s blood pressure stays within control versus not,” Ovbiagele said. “Since South Carolina has one of the highest stroke rates in the nation, and many strokes are readily preventable through good blood pressure management, targeting the maintenance of blood pressure control consistently over time following a stroke could be a helpful way to lessen the personal and public burden of stroke in our state.”
Researchers analyzed the results from the Vitamin Intervention for Stroke Prevention (VISP) trial, which enrolled 3,680 ischemic stroke patients ages 35 and older in 1996-2003. Ischemic strokes are caused by a clot in a blood vessel supplying the brain. Participants had been tested for several factors, including blood pressure levels at baseline, a month after the start of the study, at six months and every six months thereafter up to 24 months. The American Heart Association National Scientist Development Award funded this research.
Researchers determined results after controlling for age, sex and prior history of stroke, heart disease and other factors. Blood pressure was considered “controlled” at 140 mmHg over 90 mmHg or lower.
“Generally, when we have looked at the effect of blood pressure on stroke outcomes, we have looked at averages over time,” said Amytis Towfighi, M.D., study lead author and assistant professor of neurology at the Keck School of Medicine at the University of Southern California in Los Angeles. “But 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. Those fluctuations in blood pressure may be associated with greater cardiovascular risk. Changes in care management may be needed to ensure patients maintain consistent control of blood pressure.” Rather than check blood pressure during clinic visits only, it should done regularly, perhaps at home by machines that can remotely transmit the data, she said.
Reducing salt intake, eating a healthy diet (rich in whole grains, fruits and vegetables) and exercising regularly can also reduce stroke risk.
Founded in 1824 in Charleston, The Medical University of South Carolina is the oldest medical school in the South. Today, MUSC continues the tradition of excellence in education, research, and patient care. MUSC educates and trains more than 3,000 students and residents, and has nearly 13,000 employees, including approximately 1,500 faculty members. As the largest non-federal employer in Charleston, the university and its affiliates have collective annual budgets in excess of $1.7 billion. MUSC operates a 750-bed medical center, which includes a nationally recognized Children's Hospital, the Ashley River Tower (cardiovascular, digestive disease, and surgical oncology), Hollings Cancer Center (one of 66 National Cancer Institute designated centers) Level I Trauma Center and Institute of Psychiatry. For more information on academic information or clinical services, visit www.musc.edu. For more information on hospital patient services, visit www.muschealth.com.