People with systolic blood pressure above 140 mm Hg have a significantly increased risk of building up stroke-causing deposits in their aorta, according to a new Mayo Clinic study.
The study results, published this week in Circulation, show that an increase of 10 mm Hg in systolic blood pressure corresponds to a 31 percent greater chance of complex aortic atherosclerosis. Complex atherosclerosis means the deposits on the artery walls have formed irregular clumps. When these clumps break off, they may lodge in the smaller blood vessels of the brain, causing a stroke.
The findings come from the Stroke Prevention: Assessment of Risk in a Community (SPARC) study, which evaluated a random selection of Olmsted County, Minn., residents by transesophageal echocardiography (TEE) and other tests, including blood pressure measurements. A typical echocardiogram uses ultrasound waves from outside the body to generate images of the heart. The SPARC study used TEE, which involves inserting an ultrasound probe down the throat, to provide clearer images of the blood vessels and the presence or absence of atherosclerosis.
"Previous studies have pointed to the importance of keeping the diastolic blood pressure under control, especially with regard to preventing heart attacks," says Bijoy Khandheria, M.D., a Mayo Clinic cardiologist and one of the study’s authors. "As a result, the focus of treatment has been on the bottom number, and not as much attention has been paid to the top number. This study indicates that high systolic pressure also is a very important factor in raising the risk of stroke."
Dr. Khandheria says the study points to the need for physicians to pay more attention to systolic pressure, even if the bottom number is in the normal range, and for patients to take their blood pressure-lowering medications. "Atherosclerosis tends to increase with age, so people over age 60 should have their blood pressure checked in a doctor's office at least once a year," says Dr. Khandheria. "The goal is 140/90 or lower, and both numbers are important. Patients and physicians need to work together to reduce the risk of stroke, and this study shows one very important way they can do it."