Women at greater risk of subsequent stroke than men

Among patients who have suffered a single stroke, researchers at the University of Pennsylvania School of Medicine, along with colleagues at other institutions, have found that severe stenosis, or narrowing, of the arteries in the head represents a major risk factor for the development of a subsequent stroke.

Patients with recent symptoms were also at high risk. Further, women faced a greater risk of subsequent stroke than men. Their work, to be published in the January 31 issue of Circulation, lays the foundation for further studies into effective therapies to prevent secondary strokes.

The researchers' findings are part of a larger multi-site clinical investigation - specifically, the Warfarin versus Aspirin for Symptomatic Intracranial Disease (WASID) trial - which found aspirin to be the preferred medical therapy for preventing a secondary stroke. (Indeed, according to the WASID study, warfarin was associated with significantly higher rates of adverse events and provided no benefit over aspirin for preventing stroke and vascular death.)

The Penn study - which has now identified the patient-population that is most at-risk for a secondary stroke - sets the stage for additional studies to test more alternative treatments. "We need to be more aggressive in the treatment of these high-risk patients," said Scott Kasner, MD, lead author of the Circulation study and Director of Penn's Stroke Center. "Stenting and angioplasty in the brain are promising treatments for intracranial stenosis, and this study identified the target group for a new trial comparing these treatments with traditional medical therapy."

Using patient data from the WASID trial, Kasner's study analyzed five probable clinical factors that would contribute to a subsequent stroke in the territory of the initial event - including type of qualifying event (stroke or TIA), location of vessel, percent stenosis, treatment with antithrombotic medications at the time of the preliminary stroke, and time from the qualifying event to enrollment in the study. After adjusting for age, gender, and race, the researchers found that patients with severe stenosis (at or greater than 70% of the affected vessel's diameter), recent symptoms, and female gender were associated with significantly higher subsequent risk of stroke in the territory of a symptomatic intracrancial stenotic artery than other groups. "Our observations suggest that potential intervention should be considered very soon after clinical presentation, unless early intervention also increases the short-term risk," says Kasner.

"Intracranial stenting has not been evaluated in a controlled clinical trial and the effectiveness of this approach remains in question," adds Kasner.