The implications of surgeon case volume and hospital volume on outcomes of aortobifemoral bypasses in obese patients

Abstract

Background: Aortobifemoral (ABF) bypass is the gold standard for treating symptomatic aortoiliac occlusive disease. In the era of heightened interest in the length of stay (LOS) for surgical patients, this study aims to investigate the association of obesity with postoperative outcomes at the patient, hospital, and at surgeon levels.

Methods: This study used the Society of Vascular Surgery Vascular Quality Initiative suprainguinal bypass database from 2003 to 2021. The selected study cohort was divided into obese patients (body mass index ≥30) (group I) and nonobese patients (body mass index <30) (group II). Primary outcomes of the study included mortality, operative time, and postoperative LOS. Univariate and multivariate logistic regression analyses were performed to study the outcomes of ABF bypass in group I. Operative time and postoperative LOS were transformed into binary values by median split for regression analysis. A P value of .05 or less was deemed statistically significant in all the analyses of this study.

Results: The study cohort consisted of 5392 patients. In this population, 1093 were obese (group I) and 4299 were nonobese (group II). Group I was found to have more females with higher rates of comorbid conditions, including hypertension, diabetes mellitus, and congestive heart failure. Patients in group I had increased odds of prolonged operative time (≥250 minutes) and an increased LOS (≥6 days). Patients in this group also had a higher chance of intraoperative blood loss, prolonged intubation, and required vasopressors postoperatively. There was also an increased odds of postoperative decline in renal function in the obese population. Patients with prior history of coronary artery disease, hypertension, diabetes mellitus, and urgent or emergent procedures were found to be risk factors for a LOS of more than 6 days in obese patients. An increase in the surgeons' case volume was associated with lesser odds of an operative time of 250 minutes or more; however, no significant impact was found on postoperative LOS. Hospitals where 25% or more of ABF bypasses were performed on obese patients were also more likely to have LOS of less than 6 days after ABF operations, compared with hospitals where less than 25% of ABF bypasses were performed on obese patients. Patients undergoing ABF for chronic limb-threatening ischemia or acute limb ischemia had a longer LOS and increased operative times.

Conclusions: ABF bypass in obese patients is associated with prolonged operative times and a longer LOS than in nonobese patients. Obese patients operated by surgeons with more cases of ABF bypasses have shorter operative times. A hospital's increasing proportion of obese patients was related to a decreased LOS. These findings support the known volume-outcome relationship that, with a higher surgeon case volume and increased proportion of obese patients in a hospital, there is an improvement in outcomes of obese patients undergoing ABF bypass.

Keywords: Aortobifemoral bypass; Hospital volume; Obesity; Surgeon case volume.