Impact of Hospital Volume on Clinical Outcomes after Aortoiliac Stenting in Patients with Peripheral Artery Disease.

Aim: To investigate the impact of institutional volume on clinical outcomes after aortoiliac (AI) stenting in patients with symptomatic peripheral artery disease (PAD). Methods: We analyzed the clinical database from the Observational prospective Multicenter registry study on the Outcomes of peripheral arTErial disease patieNts treated by AngioplaSty tHerapy in the aortolliac artery (OMOTENASHI) registry. The volume of each institution was evaluated as the number of endovascular therapy (EVT) procedures performed in 2 years (2014-2015). High-volume centers were defined as being in the highest textile of the procedural volume (>= 611 EVT procedures in 2 years). Clinical outcomes, treatment strategies, and endovascular procedures were compared between high- and low-volume centers using a propensity score matching. Results: The propensity score matching extracted 236 pairs of patients (as many patients treated at high-volume centers and 519 patients treated at low-volume centers), with no remarkable intergroup differences in the base-line characteristics. Patients treated at high-volume hospitals had a significantly lower 12-month restenosis rate than that of patients treated at low-volume hospitals (6.5% vs. 15.8%, P=0.032), although comparable outcomes between the two groups included the technical success rate (99.6% vs. 99.8%, P=0.58) and the rate of 30-day major adverse events (0.4% vs. 0.8%, P=0.59). Conclusion: Institutional volume was associated with the 12-month restenosis rate after AI stenting for PAD, although comparable perioperative outcomes were also observed between high-volume and low-volume hospitals.