Is Clinical Success After Lower Extremity Revascularization for Ischemic Tissue Loss Affected by Method of Revascularization?

BACKGROUND: While it has been shown that the probability of clinical failure after surgical bypass for lower extremity ischemic tissue loss can be predicted by the presence of various intrinsic patient factors, it is unclear whether clinical failure can be reduced by using less invasive endovascular means. The purpose of this study is to determine clinical success rates after lower extremity revascularization regardless of interventional method, to identify factors influencing probability of failure, and to specifically examine whether success after endovascular revascularization is superior to open bypass.
METHODS: Between 1998 and 2005, 677 patients (316 endovascular and 361 open surgery) underwent revascularization for ischemic tissue loss. Revascularization was considered to be clinically successful if each of the following occurred: Reconstruction patency until wound healing, limb salvage for one year, maintenance of ambulation for one year, and survival for six months. The influence of 20 intrinsic patient factors, including type of revascularization (open versus endo) was examined using the chi-square test. Significant factors in bivariate analysis were included in a logistic regression model to determine independent predictors and probability of failure.
RESULTS: Overall clinical success was achieved in 277 (40.9%) patients. Success was statistically similar for open surgical and endovascular cohorts (44.3% and 37.0%, respectively; p=0.06). Type of intervention was not a significant factor in either bivariate or logistic regression analysis. Independent predictors of failure (Odds Ratio [95% confidence interval]) regardless of treatment type included impaired ambulatory status at the time of presentation (OR 3.24 [2.14, 4.90]), diabetes (OR 1.62 [1.14, 2.32]), ESRD (OR 1.55 [1.07, 2.23]), hyperlipidemia (OR 0.70 [0.50, 0.98]), presence of gangrene (OR 2.0 [1.42, 2.82]), and prior vascular intervention (OR 1.46 [1.02, 2.10]). Probability of failure was 35.4% (OR 1.0) if no independent predictors were present and increased with the addition of each adverse predictor. For instance, diabetic patients with impaired ambulatory status and gangrene had an 85.2% (OR 10.5) probability of failure. If the worst case scenario, a diabetic patient with ESRD, impaired ambulatory status, gangrene and a prior vascular intervention, was considered, probability of failure was a dismal 92.8% (OR 23.7).
CONCLUSIONS: Clinical success after lower extremity revascularization for ischemic tissue loss is determined by intrinsic patient factors and not by method of revascularization. These data reiterate that future investigational efforts should be focused less on method of revascularization and more on identification of patient cohorts at risk for failure regardless of treatment.