Symptomatic vertebrobasilar (VB) atherosclerosis is associated with a high risk of recurrent stroke despite optimal medical therapy. In this study, we aim to examine the associations between risk factors and recurrent major cardiovascular events (MACE) in patients with symptomatic VB stenosis randomized in the medical arm of the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) study.

Data from subjects in the medical arm of the SAMMPRIS trial with an infarct in the territory of vertebral or basilar arteries (n= 73) were analyzed. The primary outcome was MACE: defined as stroke, myocardial infarction, or other cardiovascular death during follow up.  Mean risk factor values were compared between subjects who met the primary outcome at 2 years versus those who did not, using T-tests and χ2 tests.

Among 73 patients with VB stenosis receiving medical treatment, 18 (24.6%) had recurrent MACE over a mean follow up of 2.8 years. Predictors of MACE at 2 years were increased triglyceride level (adjusted OR per 50 units increase in triglyceride 1.94, 95% CI 1.15-3.28), increased HbA1c level (adjusted OR per 1 unit increase in HbA1c 2.07, 95% CI 0.97-4.45), and lower physical activity status measured by PACE (out of target defined by PACE ≤ 4: moderate activity < 5 days per week or intense activity < 3 days per week) (2.5 ± 1.0 vs. 3.3 ± 1.8, p = 0.028).

In patients with symptomatic VB disease, improvement of medical treatment over time led to a reduction in cardiovascular event rates but this risk remains elevated as nearly 1 in 5 patients had MACE within 2 years. Further risk factor optimization and lifestyle changes are needed to reduce the rates of MACE in this patient population.