High BP worsens impact of stroke on brain function

In women who suffer a Stroke, high blood pressure before the event predicts greater declines in cognitive function afterward, results of a study suggest.

The reason may be that pre-existing damage from high blood pressure hinders Stroke recovery. Reducing blood pressure may help curb the burden of cognitive impairment among stroke survivors, study investigators conclude.

High blood pressure has been associated with silent or "subclinical" injury in the brain, but whether it increases the impact of Stroke has been unknown.

To investigate, Dr. Jacob S. Elkins, from the University of California, San Francisco, and others identified 260 women who suffered stroke out of nearly 10,000 women enrolled in their study of bone fractures between 1986 and 1988. Cognitive testing had been performed within 2 years of Stroke and then repeated at a median of 1.9 years following stroke.

Compared with women with Stroke and normal blood pressure, those with stroke and high blood pressure showed significantly greater declines in the speed at which they could complete a cognitive function test.

The average increase in time to complete the test after Stroke was 43.5 seconds in the women with high blood pressure compared with just 12.5 seconds in those with normal blood pressure.

The odds for cognitive decline after Stroke was roughly fourfold higher in women with pre-existing high BP compared with those with normal BP.

It's possible, the researchers say, that high blood pressure impedes a person's ability to tolerate or recover from brain injury caused by stroke.

SOURCE: Annals of Neurology, July 2005.