Hemostatic factors, BP surge add to morning stroke risk
MedWire News: The presence of hemostatic risk factors adds to the stroke risk associated with the morning blood pressure (BP) surge in patients with hypertension, research shows.
Like BP, hemostatic activity is elevated in the morning, say Kazuomi Kario (Jichi Medical University School of Medicine, Shimotsuke, Japan) and colleagues, so may help to explain the morning peak in cardiovascular events.
In the team's study, 43 of 514 hypertensive patients, aged at least 50 years, suffered a stroke during an average follow-up of 41 months.
Stroke was 2.5 times more likely to occur if patients were in the highest versus the lower three quartiles of plasminogen activator inhibitor (PAI)-1 levels, and 2.6 times more likely if they were in the highest versus lower three quartiles of prothrombin fragment 1 and 2 (F1+2) levels (measured in the morning).
These associations were independent of confounders including age, gender, body mass index, smoking status, and 24-hour systolic blood pressure. Patients in the highest quartiles of PAI-1 and F1+2 had levels of at least 58 ng/ml and 1.78 nmol/l, respectively.
Patients' fibrinogen levels did not affect their risk for stroke, the team reports in the European Heart Journal.
The morning BP surge is an established stroke risk factor; in the current study, each 10 mmHg rise in the morning surge, defined as the difference between morning systolic BP and the lowest nighttime levels, raised patients' stroke risk 1.2-fold.
For patients in the highest quartile of morning surge (>44 mmHg), hemostatic risk factors added further to their stroke risk, with patients in the highest quartile of PAI-1 and F1+2 having respective 3.4- and 3.3-fold risk increases relative to those in the lower quartiles.
"This additive effect may indicate that the morning BP surge and hemostatic risk factors participate in different pathophysiological processes in the development of cerebrovascular disease," comment Kario et al.
They say that their findings "might be useful in the diagnostic work-up of older hypertensive patients to identify those who have likely developed or will develop cerebrovascular diseases."
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By Eleanor McDermid