Mortality and amputation outcomes of infrainguinal bypass versus endovascular therapy based on body mass index

Obese patients have higher rates of cardiovascular disease and associated risk factors, but lower rates of peripheral artery disease and better outcomes after revascularization. This results in an obesity paradox, where obese patients have the lowest risk of adverse outcomes following treatment, while underweight and morbidly obese patients are at the highest risk. No previous studies have compared outcomes of endovascular vs open bypass within each body mass index (BMI) group. Our study aims to compare outcomes of peripheral vascular intervention (PVI) with infrainguinal bypass (IIB) stratified by patient BMI group.

The Vascular Quality Initiative database was queried for patients presenting with claudication or chronic limb-threatening ischemia (CLTI) undergoing PVI or IIB (using the great saphenous vein) from 2012 to 2023. Patients were categorized into five BMI groups: underweight (BMI ≤ 18.5 kg/m²), normal weight (BMI 18.5-24.9 kg/m²), overweight (BMI 25.0-29.9 kg/m²), obese (BMI 30.0-39.9 kg/m²), and morbidly obese (BMI 40.0-49.9 kg/m²). Multivariable logistic compared 30-day mortality for IIB vs PVI within each BMI group. Cox regression, Kaplan-Meier survival analysis, and log-rank tests assessed 1-year mortality, 1-year amputation, and 1-year amputation/death rates. Subgroup analysis was performed by indication (CLTI or claudication).

There were 118,622 patients meeting the study criteria, including 3542 underweight (3%), 33,009 normal weight (28%), 40,582 overweight (34%), 36,494 obese (31%), and 4995 morbidly obese (4%) patients. There was no significant difference in 30-day mortality between PVI and IIB in underweight patients. IIB was associated with lower 30-day mortality in normal weight (adjusted odds ratio [aOR], 0.45; 95% confidence interval [CI], 0.33-0.62) and obese (aOR, 0.78; 95% CI, 0.24-0.75) patients. Bypass was associated with lower 1-year mortality in all BMI groups, except for morbidly obese patients. It was also associated with a lower risk of 1-year amputation for normal weight (aOR, 0.82; 95% CI, 0.70-0.96) and a lower risk of 1-year amputation/death for normal weight, overweight, and obese patients. Among CLTI patients, bypass was associated with decreased 30-day and 1-year mortality risks in all but underweight patients.

This study shows significant differences in 30-day and 1-year mortality, amputation, and amputation/death rates between PVI and IIB based on BMI depending on patient BMI. Bypass was associated with better outcomes for normal weight and obese patients, and for CLTI patients across most BMI groups. This finding suggests a long-term survival benefit after IIB compared with PVI, an effect potentiated by symptom severity, except for patients otherwise at a higher operative risk regardless of procedure choice.