Determinants of outcome after endovascular therapy for critical limb ischemia with tissue loss

Abstract

Background: In this study we examine outcomes of endovascular therapy for critical limb ischemia with tissue loss and identify risk factors for failure of endovascular therapy across a panel of outcome metrics.

Methods: A retrospective review (2006-2010) of patients undergoing endovascular therapy for critical limb ischemia with tissue loss provided data for multivariate models of overall survival, amputation-free survival, limb salvage (LS), and wound healing.

Results: One hundred six patients underwent endovascular therapy for Rutherford class 5 (88%) or class 6 (12%) ischemia with ulceration and/or gangrene of the heel (15%), forefoot (16%), toe(s) (43%), calf/ankle (11%), or multiple locations (15%). Sustained limb salvage at 1 year was 87%. One-year overall survival and amputation-free survival were 65% and 49%, respectively. Multivariate regression models identified independent risk factors for reduced primary patency: Rutherford 6 ischemia (P = 0.008; HR 4.7 [95% confidence interval 1.5-14.8]) and infrapopliteal intervention (P = 0.03; HR 2.58 [95% CI 1.08-6.14]). Rutherford class 6 ischemia was independently associated with reduced assisted patency (P = 0.004; HR 5.39 [95% CI 1.74-16.73]). Wound healing was adversely affected by diabetes (P = 0.02; HR 7.0 [95% CI 1.4-36.2]), continued smoking (P = 0.04; HR 5.3 [95% CI 1.1-26.3]), and patency loss (P = 0.04; HR 4.8 [95% CI 1.1-22.30]). Rutherford class 6 ischemia was independently associated with reduced limb salvage (P < 0.0001; HR 35.1 [95% CI 5.4-231.2]) and amputation-free survival (P = 0.007; HR 3.61 [95% CI 1.4-9.18]), in addition to COPD (P = 0.01; 3.58 [95% 1.28-9.55]). Independent predictors of poor overall survival included end-stage renal disease (P = 0.03; HR 2.99 [95% CI 1.1-8.05]), history of angina (P = 0.02; HR 5.08 [95% CI 1.28-20.29]), and COPD (P = 0.001; HR 3.77 [95% CI 1.76-8.34]).

Conclusions: Both increasing severity of tissue loss as well as the presence of severe medical comorbidities are associated with poorer outcomes of endovascular therapy in these patients. Although sustained limb salvage in patients with tissue loss may be achieved with endovascular therapy, this is due to poor overall survival and a competing mortality hazard.