Predicting ambulation status one year after lower extremity bypass

Abstract

Surgeons must weigh the morbidity of lower extremity bypass (LEB) with the likelihood of a functional outcome postoperatively. We developed a model to predict ambulation status 1 year after LEB. We analyzed a prospective registry of 1561 LEB procedures performed for occlusive disease (2003-2005) in 1400 patients (50 surgeons, 11 hospitals). Ambulation status was assessed preoperatively, at discharge, and at 1-year by life-table analysis. Cox proportional hazards models were used to determine predictors of ambulation status 1 year postoperatively. The indication for surgery was claudication in 25% and critical limb ischemia (CLI) in 75%. Claudicant patients had higher primary (79% vs 73%, P < .001) and secondary (87% vs 81%, P < .001) graft patency rates and were more likely to be alive and ambulatory 1 year postoperatively (96% vs 81%, P < .001) than CLI patients. Amputation rates were 12% for CLI patients and 1% for claudicant patients (P < .001). All claudicant patients walked before surgery, and the 95% who survived 1 year postoperatively remained ambulatory. Preoperatively, 93% of CLI patients were ambulatory, and 88% of the survivors at 1 year remained ambulatory. The risk of dying or being nonambulatory 1 year postoperatively was increased in patients who were nonambulatory preoperatively (hazard ratio [HR], 1.5; 95% confidence interval [CI], 1.3-1.6; P < .0001), by increasing age of 70-79 (HR, 1.8; 95% CI, 1.2-2.6; P < .007) and 80-89 years (HR, 2.3; 95% CI, 1.5-3.7; P < .0001), by CLI (HR, 2.0; 95% CI, 1.2-3.4; P < .007), by postoperative myocardial infarction (HR, 2.5; 95% CI, 1.6-4.1; P < .001), and by major amputation (HR, 2.9; 95% CI, 2.1-4.1; P < .001). Graft thrombosis during follow-up (HR, 1.6; 95% CI, 1.1-1.8; P < .003) and living in a nursing home preoperatively (HR, 3.5; 95% CI, 1.5-7.8; P < .003) were independently associated with a higher risk of being nonambulatory at 1 year. Ambulatory and independent living status are well preserved after LEB. Risk factors of age, preoperative ambulatory ability, independent living status, CLI, graft patency, and amputation help to predict ambulatory status 1 year postoperatively. The likelihood of death or nonambulatory status at 1 year was <5% in patients with none of these risk factors to nearly 50% in patients with three or more risk factors. These variables can be used to inform decision making about whether patients should undergo LEB.