Clinical Implications of Low Body Mass Index on Endovascular Lower Extremity Revascularization

The epidemic of obesity and associated cardiovascular morbidity continues to grow, attracting public attention and healthcare resources. However, the impact of malnutrition and being underweight continues to be overshadowed by obesity, especially in patients with peripheral arterial disease (PAD). This study assesses the characteristics and outcomes of patients with low body mass index (BMI ≤ 18.5) compared to patients with nonobese BMI undergoing peripheral vascular interventions (PVI).

A retrospective analysis of patients undergoing PVI due to PAD registered in the Vascular Quality Initiative database. Patients were categorized into underweight (BMI ≤ 18.5) and nonobese BMI (BMI = 18.5-30). Patients in both groups were matched 3:1 for baseline demographic characteristics, comorbidities, medications, and indications. Kaplan-Meier analysis was done for long-term outcomes.

A total of 337,926 patients underwent PVI, of whom 12,935 (4%) were underweight, 215,728 (64%) were nonobese, and 109,263 (32%) were obese. Underweight patients were more likely to be older, female, smokers, with chronic obstructive pulmonary disorder, and more likely to present with chronic limb-threatening ischemia than nonobese patients. After propensity matching, there were 18,047 nonobese patients and 6,031 underweight patients. There were no significant differences in matched characteristics. Perioperatively, underweight patients were more likely to require a longer hospital length of stay. Underweight patients had statistically significantly higher 30-day mortality compared to patients with nonobese BMI (3% vs. 1.6%, P < 0.001) and a higher rate of thrombotic complications. As for long-term outcomes, underweight patients had a higher rate of reintervention (20% vs. 18%, P < 0.001) and major adverse limb events (27% vs. 22%, P < 0.001). The 4-year rate of amputation-free survival was significantly lower in underweight patients (70% vs. 82%, P < 0.001), and the 2-year freedom from major amputation (90% vs. 94%, P < 0.001) showed similar trends with worse outcomes in patients who were underweight.

Underweight patients with PAD are disproportionally more likely to be African American, females, and smokers and suffer worse outcomes after PVI than PAD patients with nonobese BMI. When possible, increased scrutiny and optimization of nutrition and other factors contributing to low BMI should be addressed prior to PVI.