TUESDAY, March 16, 2004 (HealthDayNews) -- Small increases in blood pressure raise the risk of having additional heart attacks, strokes and other cardiovascular problems for women who already have heart disease.
Previous research had unearthed a relationship between rising blood pressure and a risk of cardiovascular disease, but this is one of the first studies to show a similar relationship among women who already have cardiovascular disease (CVD).
The findings, which appear in the March 16 issue of Circulation, accentuate the need to aggressively monitor and control blood pressure.
"We found that, even in women with heart disease, regardless of whether they had diabetes or kidney disease, there's a risk associated with borderline blood pressure," says study author Dr. Peter J. Mason, a cardiology fellow at Boston Medical Center. "It's not proven, but perhaps these people would benefit from a lower targeted blood pressure, whether that comes from exercising and diet reduction and behavioral modification or from medications."
Mason completed this research while a National Heart, Lung, and Blood Institute-sponsored cardiovascular epidemiology fellow at the Brigham and Women's Hospital Division of Preventive Medicine in Boston.
"This study gives evidence to the fact that certain elevations in blood pressure lead to recurrent heart events and future heart events, so that we really have continued evidence to support that we have to work harder to lower blood pressure," says Dr. Nieca Goldberg, chief of women's cardiac care at Lenox Hill Hospital in New York City.
Goldberg adds that only 26 percent of women being treated for blood pressure are adequately treated.
Mason and his colleagues looked at 5,218 female health professionals who were part of the Women's Antioxidant Cardiovascular Study, which is a randomized, double-blind study looking at the prevention properties of antioxidant vitamins, folic acid and vitamins B6 and B12 among women with CVD or three or more coronary risk factors. The women chosen for this study all had confirmed heart attack, stroke, coronary artery bypass graft or angioplasty. They were followed for an average of 6.5 years. Their average age was just over 62 years.
After controlling for age, antihypertensive medication use and coronary risk factors, the researchers found that for each 10 millimeters of mercury (mm Hg) increase in systolic blood pressure (the top number), a woman's risk for future CVD events increased 9 percent. Systolic blood pressure (SBP) is the pressure when the heart beats. The lower number in the reading (diastolic blood pressure) is the pressure between beats.
Diastolic blood pressure also predicted CVD risk, but not nearly as well as systolic blood pressure.
The problem with having high blood pressure is that it causes the heart to work harder. This effort eventually enlarges and weakens the heart.
Recommendations from the Seventh Report of the Joint National Committee on Prevention, Detection and Treatment of High Blood Pressure (JNC 7) call for starting hypertensive therapy in patients with diabetes or chronic kidney disease when they have an SBP of 130 mm Hg or greater.
This new data suggests women with cardiovascular disease and slight elevations in SBP should also target their blood pressure to a lower number.