Obesity poses a significant public health issue and is implicated as an independent risk factor for cardiovascular disease.[1] Despite the medical comorbidities and surgical complications that may present with obesity, there has been a documented obesity paradox in cardiovascular surgery such that obese patients may experience improved outcomes compared to their normal weight counterparts.[2] The objective of this review was to evaluate the association between obesity and clinical outcomes in patients with peripheral arterial disease undergoing either endovascular or open lower extremity revascularization.

A systematic review and meta-analysis were performed using the following databases: MEDLINE, EMBASE, CINAHL, Web of Science, and Cochrane Library from inception until November 2021. Studies were included if they described a peripheral arterial disease (PAD) cohort undergoing open or endovascular lower extremity revascularization, compared cohorts by body mass index (BMI), and described the following outcomes: mortality, major adverse cardiovascular events (MACE), major adverse limb events (MALE), endovascular access site complications, surgical site infections, and pooled cardiac, pulmonary, renal, and infectious perioperative complications. Count data were extracted and meta-analyzed with a random-effects model. The New-Castle Ottawa Scale (NOS) was employed to assess article quality.[3] Meta-analyzed outcomes were appraised with Grading of Recommendations, Assessment, Development, and Evaluations (GRADE).[4]

8 studies [5-12] were included which ultimately detailed 171 648 patients (44 100 obese and 127 548 non-obese). Overall NOS quality scores were (M±SD) 5.9±0.8 stars, indicating a moderate risk of bias. Obese patients (BMI≥30) were more likely to be women, diabetic, and have more cardiovascular comorbidities despite being younger. There was no association between obesity and PAD severity. Obesity was associated with an overall 22% decreased mortality risk after lower extremity revascularization (RR 0.78, 95% CI [0.71, 0.85], p<.001, I^2=0%, GRADE: very low quality). Subgroup analysis by intervention type showed similar findings (Endovascular RR 0.79, 95% CI [0.71, 0.87], p<.001, I^2=0%; Open RR 0.70, 95% CI [0.51, 0.95], p=.024, I^2=43%). Obesity was associated with a 14% decreased risk in MACE for open surgery only (RR 0.86, 95% CI [0.76, 0.98], p=.021, I^2=0%, GRADE: very low quality). Obesity was associated with an increased risk for surgical site infections pooled across intervention types (RR 1.52, 95% CI [1.22, 1.89], p<.001, I^2=29%, GRADE: very low quality). There was no association between obesity and MALE (RR 1.02, 95% CI [0.93, 1.13], p=.65, I^2=31%, GRADE: very low quality) or endovascular access site complications (RR 1.73, 95% CI [0.68, 4.38], p=.25, I^2=97%, GRADE: very low quality). Pooled perioperative complications did not differ between obese and non-obese cohorts (RR 1.04, 95% CI [0.84, 1.28], p=.73, I^2=92%, GRADE: very low quality). Subgroup analysis by intervention type still demonstrated no difference in pooled perioperative complications (Endovascular RR 1.06, 95% CI [0.76, 1.47], p=.73, I^2=55%; Open RR 1.01, 95% CI [0.78, 1.31], p=.92, I^2=68%).

Obesity was associated with reduced mortality risk in both endovascular and open surgery while a reduction in MACE risk was only observed in open surgery. However, there was an increased risk for surgical site infections in obese individuals. Obesity did not influence risk of MALE, endovascular access site complications, or perioperative complications. The GRADE quality of evidence was rated as very low for each meta-analyzed outcome, largely due to the retrospective study designs. A nuanced evaluation of BMI classification as a preoperative surgical risk factor is warranted.

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