Effect of obesity on patient outcomes after aortobifemoral bypass in the treatment of aortoiliac occlusive disease

Abstract

Objective

The purpose of this study was to evaluate the impacts of obesity on patients undergoing aortobifemoral bypass for aortoiliac occlusive disease (AIOD). AIOD is an atherosclerotic disease of the suprainguinal arteries, and treatment approaches are often guided by the TASC II classification. The obesity paradox, a phenomenon where higher-than-normal BMI individuals exhibit better outcomes in various medical conditions, has yet to be fully understood in the context of AIOD.

Methods

The American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database was queried for AIOD cases between January 1, 2011 and December 31, 2016. All patients included in the AIOD targeted files were eligible for inclusion unless their BMI was missing. Patient demographics and surgical characteristics were analyzed across BMI, categorized as underweight (<18.5), normal (18.5–24.9), overweight (25.0–29.9), obese (30–34.9), and very obese (≥35). Multivariable logistic and linear regression models, adjusting for demographics, comorbidities, and AIOD symptoms, were used to estimate the association between BMI and patient outcomes.

Results

Overall, 4885 patients met inclusion criteria, of which 274 (6%) patients were underweight, 1720 (35%) were normal weight, 1649 (32%) were overweight, 843 (16%) were obese, and 399 (8%) were very obese. Among all groups, neither age nor symptoms were significantly different. The functional status of the patients across all groups was also similar. Compared to normal-weight patients, obese and very obese patients were significantly more likely to be diabetic (34% and 50% vs 16%) and have hypertension (82% and 84% vs 5%), p < .0001. Both obese (OR 2.11, 95% CI 1.47, 3.04) and very obese patients (OR 2.94, 95% CI 1.95, 4.45) had significantly higher incidences of infection. Very obese patients also had a higher incidence of pneumonia (OR 2.03, 95% CI 1.11, 3.74) and prolonged ventilator requirement (OR 3.09, 95% CI 1.86, 5.14) compared to normal-weight patients. No differences were seen in mortality (p = .92) or length of stay (p = .20).

Conclusion

An elevated body mass index (BMI) is associated with a higher vulnerability to infection, pneumonia, and an extended need for ventilation after open aortobifemoral bypass surgery. However, there was no association between BMI and 30-day mortality or duration of hospitalization in patients who had AOBF bypass.