Association Between Obesity and Outcomes Following Endovascular Aneurysm Repair

Abstract

Obesity is prevalent in patients with abdominal aortic aneurysms (AAA). There is an association between increasing body mass index (BMI) and increased overall cardiovascular mortality and morbidity. This study aims to assess the difference in mortality and complication rates between normal weight (NW), overweight (OW), and obese patients undergoing endovascular aneurysm repair (EVAR) for infrarenal AAA. This is a retrospective analysis of consecutive patients undergoing EVAR for AAA between January 1998 and December 2019. Weight classes were defined as: BMI<18.5kg/m2, underweight; BMI 18.5-24.9kg/m2, NW; BMI 25.0-29.9kg/m2, OW; BMI 30.0-39.9kg/m2, obese; BMI>39.9kg/m2 morbidly obese. Primary outcomes were long-term all-cause mortality and freedom from reintervention. Secondary outcome was aneurysm sac regression (defined as a reduction in sac diameter of 5mm or more). Kaplan-Meier survival estimates and mixed model analysis of variance were used. The study included 515 patients (83% males, mean age 77±8years) with a mean follow-up of 3.8±2.8years. In terms of weight class, 2.1% (n=11) were underweight, 32.4% (167) were NW, 41.6% (n=214) were OW, 21.2% (n=109) were obese, and 2.7% (n=14) were morbidly obese. Obese patients were younger (mean difference -5.0years) but had a higher prevalence of diabetes mellitus (33.3% vs. 10.6% for NW) and dyslipidemia (82.4% vs. 60.9% for NW). Obese patients had similar freedom from all-cause mortality (88%) compared to OW (78%) and NW (81%) patients. The same findings were evident for freedom from reintervention where obese (79%) was similar to OW (76%) and NW (79%). At a mean follow-up of 5.1±0.4years, sac regression was observed similarly across weight classes at 49.6%, 50.6%, and 51.8% for NW, OW, and obese, respectively (P=0.501). There was a significant difference in mean AAA diameter pre- and post-EVAR [F(2,318)=24.37, P<0.001] across weight classes. NW [mean reduction 4.8mm (2.0-7.6mm, P<0.001)], OW [mean reduction 3.9mm (1.5-6.3mm, P<0.001)], and obese [mean reduction 5.7mm (2.3-9.1mm, P<0.001)] achieved similar reductions. Obesity was not associated with increased mortality or reintervention in patients undergoing EVAR. Obese patients achieved similar rates of sac regression on imaging follow-up.