Surgeon experience versus volume differentially affects lower extremity bypass outcomes in contemporary practice.

Background: Calls for minimum case thresholds to guide surgeon credentialing paradigms are increasing in contemporary practice. To date, the volume-outcome relationship and the role of surgeon experience as a proxy for quality have remained primarily focused on nonvascular extirpative surgery and aneurysm repair. However, it is unclear whether these data can be rightly extrapolated to predict lower extremity bypass (LEB) outcomes. Thus, the purpose of the present study was to examine whether the annualized case volume vs surgeon experience is more consequential in predicting for successful LEB reconstruction.
Methods: A total of 25,852 procedures with sufficient 1-year follow-up data from the Society for Vascular Surgery Vascular Quality Initiative infrainguinal bypass registry (2003-2019) were reviewed for chronic limb threatening ischemia among patients undergoing infrageniculate reconstruction. The procedures were categorized according to surgeon years of practice experience at surgery (ie, 0-5, 6-10, 11-15, >15 years) and the number of LEB procedures performed by the surgeon during the year of surgery (volume quartiles: 1-8, 9-14, 15-21, and >21). Mixed effects logistic and Cox regression models were used to assess the effects of experience, volume, and their interaction on outcomes.
Results: Increasing practice experience was more significantly associated with a reduction of in-hospital complications (odds ratio, 0.97; 95% confidence interval [CI], 0.96-0.99; P = .002) and the risk of major adverse limb events (odds ratio, 0.94; 95% CI, 0.92-0.97; P < .0001) compared with the volume. Increasing experience and volume were both associated with increased freedom from thrombosis (hazard ratio, 0.95; 95% CI, 0.93-0.98; P = .001). In contrast, neither experience nor volume had any significant association with early mortality. However, a higher volume was associated with diminished long-term survival (hazard ratio, 1.04; 95% CI, 1.0-1.1; P = .01). The most experienced surgeons (>15 years' experience) were significantly more likely to perform LEB for rest pain (P < .0001). No significant differences were found in the bypass rates among patients with tissue loss. The most experienced and highest volume surgeons were more likely to use an autogenous and/or composite conduit, in situ reconstruction, and/or pedal targets (P < .05). Similarly, more experienced and higher volume surgeons had less blood loss and shorter procedure times (P < .0001). Overall, the most experienced surgeons (>15 years' experience) were significantly more likely to have a higher volume with a diminished risk for all LEB outcomes.
Conclusions: Surgeon experience appears to have the most important role in predicting for overall LEB performance with improved in-hospital outcomes and major adverse limb events. The more experienced surgeons performed more complex reconstructions with fewer complications. These findings have significant clinical and educational implications as our most experienced surgeons approach retirement. Mentorship strategies to facilitate ongoing technical development among less experienced surgeons are imperative to sustain optimal limb salvage outcomes and have significant ramifications regarding expectations for regulatory and credentialing paradigms.
(Copyright © 2021 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)