Determinants of functional outcome after revascularization for critical limb ischemia: an analysis of 1000 consecutive vascular interventions.

BACKGROUND: When reporting standards for successful lower extremity revascularization were established, it was assumed that arterial reconstruction, patency, and limb salvage would correlate with the ultimate goal of therapy: improved functional performance. In reality, factors determining improvement of ambulation and maintenance of independent living status after revascularization have been poorly studied. The purpose of this study was to assess the important determinants of functional outcome for patients after intervention for critical limb ischemia.
METHODS: The results of 1000 revascularized limbs from 841 patients were studied. Indications were rest pain, 41.1%; ischemic ulceration, 35.6%; gangrene, 23.3%; infrainguinal, 70.9%; aortoiliac, 24.2%; and both, 4.9%. Treatment was by endovascular intervention, 35.5%; open surgery, 61.7%; and both, 2.8%. Patient were mean age of 68 +/- 12 years, and 56.6% were men, 74.7% were white, 54.2% had diabetes mellitus, 67% were smokers, 13.4% had end-stage renal disease and were on dialysis, and 36% had prior vascular surgery. Patients were treated with conventional therapy by fellowship-trained vascular specialists at a single center and were analyzed according to the type of intervention, the arterial level treated, age, race, gender, presentation, the presence of diabetes, smoking history, end-stage renal disease, coronary disease, hypertension, hyperlipidemia, obesity, chronic obstructive pulmonary disease, previous stroke, dementia, prior vascular surgery, preoperative ambulatory status, limb loss <or=1 year of treatment, and independent living status. The technical outcomes of reconstruction patency and limb salvage as well as the functional outcomes of survival, maintenance of ambulation, and independent living status were measured for each variable using Kaplan-Meier life-table analysis, and differences were assessed using the log-rank test. A Cox proportional hazards model was used to assess independent predictors of outcome and obtain adjusted hazard ratios and 95% confidence intervals.
RESULTS: At 5 years, 72.4% of the entire cohort had a patent reconstruction and 72.1% had an intact limb. Overall 5-year functional outcomes were 41.9% for survival, 70.6% for maintenance of ambulation, and 81.3% for independent living status. Outcome was not significantly affected by the type of treatment (endovascular or open surgery) or by the level of disease treated (aortoiliac, infrainguinal, or both). The most important independent, statistically significant predictors of particularly poor functional outcome were impaired ambulatory ability at the time of presentation (70% 5-year mortality, hazard ratio, 3.34; 39.5% failure to eventually ambulate, hazard ratio, 2.83; 30% loss of independent living status, hazard ratio, 7.97), and the presence of dementia (73% late mortality, hazard ratio, 1.57; 41.2% failure to eventually ambulate, hazard ratio, 2.20; 46.4% loss of independent living status, hazard ratio, 5.44). These factors were even more predictive than limb amputation alone.
CONCLUSION: Functional outcome for patients undergoing intervention for critical limb ischemia is not solely determined by the traditional measures of reconstruction patency and limb salvage, but also by certain intrinsic patient comorbidities at the time of presentation. These findings question the benefit of our current approach to critical limb ischemia in functionally impaired, chronically ill patients--patients who undoubtedly will be more prevalent as our population ages.