by Martha Kerr
Last Updated: 2007-10-29 15:12:26 -0400 (Reuters Health)
NEW YORK (Reuters) – Preoperative brachial pulse pressure, an index of vascular stiffness, is a strong predictor of stroke following cardiac surgery, and it is independent of chronological age, a Johns Hopkins team reports in the October issue of Hypertension.
In a retrospective review, Dr. Daniel Nyhan at Johns Hopkins Hospital in Baltimore, Maryland, and colleagues assessed stroke risk factors in 703 patients who underwent cardiac surgery and were followed for a mean of 348 days. During that time, 42 patients experienced a stroke.
Stroke patients had a significantly higher average pulse pressure (81.2 mm Hg) compared with patients who did not have strokes (64.5 mm Hg).
The unadjusted hazard ratio for stroke was 1.32 for every 10 mm Hg increase in pulse pressure. "This relationship remained highly significant (HR: 2.62 for each 10 mm Hg increase in pulse pressure) in the adjusted model, which included age," the team reports.
Stroke-free survival was significantly higher if pulse pressure was less than 72 mm Hg compared with a pulse pressure greater than 72 mm Hg.
Co-investigator Dr. Dan E. Berkowitz told Reuters Health that "vascular stiffness is increasingly recognized as a risk factor for cardiovascular disease…Vascular age, rather than chronological age, is the primary factor affecting stiffness."
Diet, lifestyle modification and blood pressure medications mitigate stroke risk in the long-term. "In the short term, for the cardiac surgery patient, it’s important to maintain blood flow to the brain," Dr. Berkowitz said.
Dr. Nyhan commented that "hypoperfusion appears to increase risk of stroke in cardiac surgery," and that it may be beneficial if the blood pressure is kept somewhat high while the patient is on the heart-lung bypass machine.