Prehypertension linked to MI and CAD risk, not stroke risk

No stroke risk was found in patients with blood pressures in the range of 120/80 mm Hg to 139/89 mm Hg.

Research from a Framingham Heart Study cohort suggests that prehypertension should be considered part of the global risk for heart disease. In the study, the condition was associated with risk of myocardial infarction and coronary artery disease but not with stroke.

“This finding seems puzzling because it has been well-documented that hypertension is a much more powerful risk factor for stroke than it is for coronary artery disease,” said Franz Messerli, MD, director of the hypertension program at St. Luke’s-Roosevelt Hospital and editor of Cardiology Today’s Hypertension and Vascular Disease section.

“Perhaps it should not surprise us that the risk of stroke is distinctly different with prehypertension. Conceivably, at this early stage, prehypertension is merely a marker of other abnormalities such as hyperlipidemia or insulin resistance. We should perhaps consider prehypertension as a guidepost signaling an increased global risk for cardiovascular disease,” Messerli said.

Carl Pepine

Carl Pepine, MD, chief of the division of cardiovascular medicine at the University of Florida and chief medical editor of Cardiology Today, said that cardiologists are becoming more concerned about prehypertension as evidence continues to mount about its risk.

“We are now very concerned about blood pressures within the so-called ‘normal’ range as epidemiology data and more recent trial data from NORMALIZE and INVEST show an important influence of blood pressure rise between 120 mm Hg and 140 mm Hg on coronary artery disease and related cardiovascular outcomes,” Pepine said.

The current study evaluated the risk associated with prehypertension in a cohort of 5,181 patients. JNC 7 had defined prehypertension as BP levels between 120 mm Hg to 139 mm Hg/80 mm Hg to 89 mm Hg.

Patients who had prehypertension were compared to those with hypertension, defined as a BP >140 mm Hg/90 mm Hg, and those who were classified as normotensive. The mean age of the patients was 44 years, and 45% were men.

Risk

After 11,116 person observations and a mean follow-up of 9.9 years, researchers found that prehypertension was not associated with an increased risk for an atherothrombotic brain infarction (RR=2.2; 95% CI, 0.5 to 9.3).

However, after 11,802 person observations with a mean follow-up of 9.7 years, prehypertension was associated with an increased risk for MI (RR=3.5; 95% CI, 1.6 to 7.5), and an increased risk for CAD after 11,570 person observations (RR=1.7; 95% CI, 1.2 to 2.4).

Adnan I. Qureshi

Adnan I. Qureshi, MD, professor and director of the cerebrovascular program, Zeenat Qureshi Stroke Research Center, at the University of Medicine and Dentistry of New Jersey, led the study. He said the rate of prehypertension is higher in the United States than the rate of hypertension.

“Today the guidelines suggest that someone who has prehypertension essentially just needs to have diet modification and exercise. There is no recommendation to actually start medication,” Qureshi told Cardiology Today. “However, I would suggest that we begin evaluating the potential benefit of therapy in this group of patients.”

Messerli said that patients with prehypertension may benefit from statin therapy. “Given the findings in this study, it might be more appropriate to address the global risk in these patients and regular exercise or weight loss.

“Lipid-lowering therapy with a statin may be considerably more efficacious than merely lowering millimeters of mercury by antihypertensive therapy,” Messerli said. – by Jeremy Moore

For more information:

• Qureshi AI, Suri MFK, Kirmani JF, et al. Is prehypertension a risk factor for cardiovascular diseases? Stroke. 2005;36:1863.