Slightly High Blood Pressure Increased Stroke Risk

Stroke risk rose even when blood pressure was just above normal but not considered high

(RxWiki News) While high blood pressure certainly raises stroke risk, prehypertension may also substantially up the odds of having a cardiovascular event.

When a person has a high blood pressure (hypertension), he or she is more likely to have a clot form in a blood vessel leading to the brain (ischemic stroke) or to have a blood vessel burst (hemorrhagic).

A new study found that stroke risk still increased significantly in people who had blood pressure that was above normal but not considered high (prehypertension).

"Exercise regularly to help reduce high blood pressure."

Dingli Xu, MD, of Southern Medical University in Guangzhou, China, and his colleagues conducted a review of 19 prospective studies, representing more than 760,000 participants, regarding prehypertension and stroke.

For their analysis, these researchers separated patients into groups consisting of those with hypertension (defined here as above 140/90 mm Hg) and those with prehypertension (between 120/80 mm Hg and 140/90). They further investigated the prehypertension group, dividing them into those with high prehypertension above 130/85 and those with low prehypertension between 120/80 and 135/85.

Measured in millimeters of mercury, systolic pressure (the top number) is the maximum force of the blood in the arteries, and diastolic pressure (the lower number) is the pressure when the heart is relaxed. The American Heart Association defines normal blood pressure as less than 120 for systolic and less than 80 for diastolic.

After adjusting for factors that could increase the risk of stroke, such as high cholesterol, diabetes and smoking, the researchers found that those with prehypertension were 66 percent more likely to have a stroke than those who had normal blood pressure.

The authors of this study noted that nearly one in five strokes in the study population may have been related to prehypertension.

Individuals with high prehypertension were more likely to face stroke than those with low prehypertension. Compared to those with normal pressure, the high-range individuals had a 95 percent greater stroke risk, and the low-range patients had a 44 percent greater risk.

“Considering the high proportion of the population who have higher than normal blood pressure, successful treatment of this condition could prevent many strokes and make a major difference in public health,” said Dr. Xu in a press statement.

He recommended that prehypertension should be managed with changes in diet and exercise to help reduce the risk of stroke, adding that there is not enough research yet to recommend treating prehypertension with blood pressure medication.

"More research should be done on using blood pressure drugs for people with prehypertension,” Dr. Xu said.

This study was published March 12 in Neurology.

Review Date: 
March 12, 2014