Prehypertension Triples Heart Attack Risk

"If we were to eliminate prehypertension, we could potentially preventabout 47 percent of all heart attacks," said the study's lead authorAdnan I. Qureshi, M.D., professor and director of the CerebrovascularProgram in the Zeenat Qureshi Stroke Research Center at the Universityof Medicine and Dentistry of New Jersey in Newark.

Normal blood pressure is lower than 120/80 millimeters of mercury (mmHg). Prehypertension is systolic blood pressure between 120 and 139and/or diastolic pressure between 80 and 89 mm Hg. (Systolic pressureis the force in the arteries when the heart beats and diastolicpressure is the force when the heart is at rest.) Hypertension is bloodpressure 140/90 mm Hg or higher.

"There is a gray zone, where you are not hypertensive but your blood pressure is not normal either," he said.

More than a year ago, a national committee coined the term"prehypertension" for this gray area. But until this study, Qureshisaid, physicians and the public knew little about what this term meant.About 59 million people in the United States are prehypertensive.

Researchers examined existing data from the Framingham Study and foundthat a prehypertensive person is more than three times more likely tohave a heart attack and 1.7 times more likely to have heart diseasethan a person with normal blood pressure.

They did not find a significantly increased risk of stroke among thosewith prehypertension. "This is somewhat surprising, but it may berelated to the small number of stroke events in the study," Qureshisaid. "The differential effect in this gray zone may be mediatedthrough factors other than blood pressure, such as insulin resistance."

Researchers also investigated the population's attributable risk, whichdetermines how a disease will be impacted if that risk factor wereeliminated.

"While we classically recommend lifestyle modifications such as weightcontrol, regular physical activity and changes in diet for people withprehypertension, these findings raise the question of whether we shouldtreat prehypertensive patients more aggressively."

Co-authors are M. Fareed K. Suri, M.D.; Jawad F. Kirmani, M.D.; Afshin A. Divani, Ph.D.; and Yousef Mohammad, M.D.Editor's note: For more information on stroke, visit the American Stroke Association Web site: strokeassociation.org.