Blood pressure control linked to reduced myocardial infarction, and vascular death.
Preventing stroke is a major concern. Among the 750,000 Americans who have a stroke each year, five to 14 percent will have a second stroke within a year and within five years stroke will recur in 24% of women and 42% men, according to the National Stroke Association.
Blood pressure (BP) reduction lowers vascular risk after stroke; however, little is known about the relationship between consistency of BP control and risk of subsequent vascular events.
In this new study Dr. Amytis Towfighi, MD, Assistant Professor of Neurology at USC Keck School of Medicine at the University of Southern California in Los Angeles, California and colleges in a post hoc analysis (looking at data after an experiment has been done in search of data,) of the Vitamin Intervention for Stroke Prevention trial of 3,680 participants with recent ischemic stroke (under 120 days) participants ages 35 and older in 1996-2003. Ischemic strokes occur as a result of an obstruction within a blood vessel supplying blood to the brain.
Participants had been tested for several risk 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 results showed only 30% of participants had BP controlled more than 75% of the time.
Among participants with elevated blood pressure at baseline (153 mm Hg)the risk of a second stroke was reduced by 54% among participants who kept their blood pressure under control more than 75% of the time compared to participants who had kept their blood pressure under control only 25% of the time.
In their conclusion the researchers write “In this rigorous clinical trial, fewer than one third of patients with stroke had BP controlled ≥75% of the time for 2 years. Furthermore, consistency of BP control among those with elevated baseline systolic BP was linked to reduction in risk of recurrent stroke and stroke, myocardial infarction, and vascular death.”
According to Dr. Towfighi who is also Chair of the Neurology Department and Director of the Acute Neurology/Acute Stroke Unit at Rancho Los Amigos National Rehabilitation Center commented “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.” “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, Dr. Towfighi said.
“One of the things we really emphasize is getting patients involved in their own care, and learning how to control their risk factors,” she comments.
Reducing salt intake, eating a healthy diet (rich in whole grains, fruits and vegetables) and exercising regularly can also reduce stroke risk.
With the low percentage of trial participants controlling their blood pressure from one check to the next, “you can only imagine how poor blood pressure control is outside of the clinical trial setting,” Towfighi said.
In the study, participants with a history of heart attacks were most likely to keep their blood pressure under control most of the time, possibly suggesting patients and healthcare practitioners are more aware of controlling blood pressure after heart attack but less diligent after stroke.
In January of last year, Dr. Towfighi and colleagues presented a study at the American Academy of Neurology’s 65th Annual Meeting in San Diego.
In that study the team found that people who are depressed after a stroke may have three times the risk of dying early and four times the risk of death from stroke than people who have not experienced a stroke or depression, according to the Keck School of Medicine of USC news release.