Institutional Volume and Initial Results for Endovascular Treatment for Chronic Occlusive Lower-Extremity Artery Disease: A Report From the Japanese Nationwide Registry.

PURPOSE: Chronic total occlusion (CTO) remains as a major target for endovascular treatment (EVT) in improving symptomatic lower-extremity artery disease (LEAD). However, despite the technical demand and learning curve for the procedure, volume-outcome relationship of EVT targeted for CTO in symptomatic LEAD remains unclear.

MATERIALS AND METHODS: Data were obtained from a nationwide registry for EVT procedures limited to the Japanese Association of Cardiovascular Intervention and Therapeutics between January 2018 and December 2020 from 660 cardiovascular centers in Japan. In total, 96 099 patients underwent EVT for symptomatic LEAD, and 41 900 (43.6%) underwent CTO-targeted EVTs during the study period. Institutional volume was classified into quartiles. The association of institutional volumes with short-term outcomes was explored using the generalized linear mixed model using a logit link function, in which, interinstitution variability was used as a random effect.

RESULTS: The median institutional volume for all EVT cases per quartile was 29, 68, 125, and 299 cases/year for the first, second, third, and fourth quartiles, respectively. With each model analysis, the adjusted odds ratios (ORs) for technical success were significantly lower in patients who underwent EVT in institutions within the first quartile (<52 cases/year) than in the other quartiles ( P < .01, respectively). On the contrary, the adjusted ORs for procedural complications were significantly higher in the first and second quartiles than in the third and fourth quartiles ( P < .01, respectively).

CONCLUSION: In contemporary Japanese EVT practice, a higher institutional volume but not operator volume was associated with a higher technical success rate and a lower procedural complication rate in patients with symptomatic LEAD involving CTO lesions.

CLINICAL IMPACT: EVT for CTO lesions is still challenging for clinicians because of difficulties of wire/devise crossing or high procedural complications rate. Our study demonstrated that a higher institutional volume but not operator volume was associated with a higher technical success rate and a lower procedural complication rate in patients with symptomatic LEAD involving CTO lesions. In contemporary Japanese practice, a higher institutional experience has better impacts on short-term clinical outcomes. Future research should determine the relationship between institutional volume and long-term clinical outcomes.