Predicting ambulation status one year after lower extremity bypass.

INTRODUCTION

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.