Center volume and the outcomes of percutaneous transluminal angioplasty and stenting in patients with symptomatic intracranial vertebrobasilar stenoses: A meta-analysis

Background: Evidence for the preventative effects of percutaneous transluminal angioplasty and stenting (PTAS) on the recurrence of stroke in patients with severe intracranial vertebrobasilar stenoses (IVBS) varies, and the influence of study characteristics on the study outcomes have not been determined. Methods: A study level based meta-analysis was performed to investigate the influence of baseline characteristics on the 30-day and follow-up stroke recurrence or death in symptomatic IVBS patients receiving PTAS. Relevant single center studies were retrieved by searching PubMed and Embase. A random effect model was applied to synthesize the outcomes. Meta-regression and subgroup analyses were performed to evaluate the potential influence of study characteristics on outcomes. Results: Fifteen cohort studies comprising 554 symptomatic IVBS patients were included. PTAS was associated with an 8% incidence of stroke recurrence or death (95% CI: 5% to 12%) in IVBS patients within 30 days, and 8 per 100 person-years (95% CI: 5 to 11 per 100 person-years) of cumulative stroke recurrence or death during follow-up. Meta-regression indicated that the center volume, as defined by the numbers of cases per year, was negatively correlated with 30-day (regression coefficient = -0.09, p = 0.02) and follow-up (regression coefficient = -0.60, p = 0.01) stroke recurrence or death. Age, gender, or comorbidities have no significant effect on the outcomes. Conclusions: Centers of higher procedural volume may be associated with better clinical outcomes for symptomatic IVBS patients receiving PTAS.