Preoperative Functional Status Predicts Perioperative Outcomes After Infrainguinal Bypass Surgery

Objective: Infrainguinal surgical bypass (BPG) is a durable method for lower extremity revascularization, but is accompanied by significant 30-day morbidity and mortality (MM). The goal of this study is to relate preoperative functional status, a defined metric in the National Surgical Quality Improvement Program (NSQIP) database, to perioperative MM.

Methods: Between January 1, 2005 and December 31, 2007, all patients who underwent BPG from the NSQIP private sector database were reviewed. The primary end-point was 30-day MM. Patients were stratified by preoperative functional status: independent (IND) vs dependent (DEP). Associated patient demographic/clinical data were analyzed using univariate and multivariate methods. Composite odds ratios were constructed with clusters of high-risk comorbidities.

Results: There were 5639 BPG patients (4600 [81.6%] IND and 1039 [18.4%]) DEP. DEP patients were significantly older (71.6 +/- 11.8 vs 66.8 +/- 11.8 years; P < .0001), had more chronic obstructive pulmonary disease (COPD) (16.7% vs 11.4%; P < .0001), diabetes (54.2% vs 40.7%; P < .0001), dialysis dependence (16.4% vs 5.6%; P < .0001), and critical limb ischemia (64.6% vs 44.0%; P < .0001). DEP patients had a higher incidence of death (6.1% vs 1.5%; P < .0001) and major complications (30.3% vs 14.2%; P < .0001). DEP was an independent predictor of major complications (odds ratio [OR]: 2.0; 95% confidence interval [CI]: [1.7-2.4]; P < .0001) major systemic complications (2.5 [1.9-3.2]; P < .0001), major operative site complications (1.6 [1.4-1.9]; P < .0001) and death (2.3[1.6-3.4]; P < .0001). The combination of DEP with emergency surgery, Cr > 1.8, or rest pain increased the odds of major complications by five, seven, or 11-fold, respectively. The combination of DEP with hemodialysis, emergency surgery, or age > or = 80 years increased the odds of death by 13, 38, or 87-fold, respectively.

Conclusion: Preoperative DEP is significantly correlated with all adverse 30-day outcomes in BPG patients. Furthermore, when combined in high-risk composites with specific preoperative clinical variables, DEP is associated with prohibitive MM, thereby identifying patient cohorts that may be unsuitable for BPG.