Stroke-free survival and its determinants in patients with symptomatic vertebrobasilar stenosis: a multicenter study.

Objective: We sought to determine the long-term stroke-free survival of patients who present with ischemic events related to intracranial vertebrobasilar stenosis.
Methods: A retrospective cohort of patients diagnosed with symptomatic vertebrobasilar stenosis on the basis of magnetic resonance angiography and/or conventional angiography was identified at four academic medical centers. Patients' clinical and follow-up information was obtained through hospitalization records, clinic visits, and telephone interviews. Kaplan-Meier analysis was performed to determine the rate of stroke-free survival for a 5-year period. Cox proportional hazards analysis was performed to determine the effect of demographic and clinical factors on stroke-free survival.
Results: A total of 102 patients were included, whose mean age was 64 +/- 12 years. Fifty-five (54%) of the patients were men. The mean follow-up period was 15 +/- 15.9 months (range, 1-60 mo). During the follow-up period, 14 (14%) of the patients experienced recurrent stroke. The overall mortality rate was 21% (n = 21). Stroke-free survival, calculated by using the Kaplan-Meier curve, was 76% at 12 months (95% confidence interval [CI], 66-83%) and 48% at 5 years (95% CI, 27-65%). The risk of recurrent stroke was 10.9 per 100 patient-years, and the rate of recurrent stroke and/or death was 24.2 per 100 patient-years. Cox proportional hazards analysis revealed that increasing age (hazards ratio, 1.05; 95% CI, 1.00-1.09) decreased stroke-free survival. Treatment with either antiplatelet agents or warfarin (hazards ratio, 0.018; 95% CI, 0.003-0.11) had a protective effect on stroke-free survival after adjusting for age, sex, race, hypertension, diabetes mellitus, smoking, hyperlipidemia, and lesion location.
Conclusion: A low rate of stroke-free survival is observed in patients with symptomatic vertebrobasilar stenosis. Further studies are required to evaluate new medical and endovascular treatment options for this group of patients to improve long-term stroke-free survival.