A team in Brazil studied blood pressure in 115 stroke patients. The average blood pressure upon hospital admission was 160/94 mm Hg (mercury). Blood pressure dropped in all patients either spontaneously or with medication during the first 24 hours after stroke (the acute phase). At follow-up three months later, 44 patients had a poor outcome, meaning at least moderate disability. They needed assistance to complete daily activities like walking, eating or grooming. The risk of poor outcome increased almost twofold with every 10 percent decrease in systolic blood pressure (the top number) during the first 24 hours.
Systolic blood pressure varied an average of 31 percent in the poor outcome group during the first 24 hours, compared to an average of 26 percent in the other patients. When blood pressure drops a lot in the acute phase, the blood flow to brain tissue is reduced, which can cause more damage.
"The amount of blood pressure variation made the difference between a poor outcome and a good one," said neurologist and lead author Jamary Oliveira-Filho, MD, PhD, of the Hospital Sao Rafael and the Federal University of Bahia in Salvador, Brazil. "Blood pressure is only one variable in the outcome, but even small changes can make a difference in the big picture."
An editorial in the same issue of Neurology says that despite limitations, the study adds to the discussion of risk vs. benefit in lowering blood pressure immediately after stroke.
"While 'lower is better' for preventing first and subsequent strokes, there is a growing sentiment that 'high is good' in the acute phase," said neurologist and editorial author Karen C. Johnston, MD, MSc, of the University of Virginia Health System, Charlot
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Contact: Marilee Reu
mreu@aan.com
651-695-2789
American Academy of Neurology
27-Oct-2003