Impact of renal insufficiency on clinical outcomes in patients with critical limb ischemia undergoing endovascular revascularization

Abstract

Background: Patients with renal insufficiency (RI) are frequently excluded from trials assessing various endovascular revascularization concepts in critical limb ischemia (CLI) although information on clinical outcomes is scarce.

Methods: Consecutive patients with CLI undergoing endovascular lower limb revascularization during a 4.5-year time interval at a tertiary referral center were prospectively followed over a 12-month period. Patients were grouped according to renal function defined as normal (estimated glomerular filtration rate [eGFR] ≥ 60 mL/min/1.73 m(2); n = 108, 49.5%), moderate RI (eGFR ≥ 30-59 mL/min/1.73 m(2); n = 86, 39.5%) and severe RI, including dialysis (eGFR < 30 mL/min/1.73 m(2); n = 24, 11%). Clinical endpoints assessed were sustained clinical success, peri- and postprocedural mortality and major, above-the-ankle amputation. Sustained clinical improvement was defined as an upward shift of at least one category on the Rutherford classification compared with baseline to a level of claudication without repeated revascularization or unplanned amputation in surviving patients. Survival analysis was performed using the Kaplan-Meier method. Multivariate regression analysis was conducted in separate models for all above-mentioned clinical endpoints.

Results: A total of 208 patients (218 limbs, mean age 77.1 ± 9.5, 131 men) underwent endovascular revascularization. Technical success rate was 95.2%, 92.5%, and 100% in patients without, moderate or severe RI. Sustained clinical success was 81.7%, 74.1%, and 51.5% in patients with normal renal function, 87.8%, 67.0%, and 63.3% with moderate, and 81.0%, 64.6%, and 50.2% with severe RI (P = .87 by log-rank) at 2, 6, and 12 months. Accordingly, major amputation rates were 9.9%, 18.2%, and 20.8% vs 9.9%, 22.6%, and 24% vs 12.5%, 16.7%, and 21.1% (P = .83, by log-rank). Mortality rates were 8.4%, 17.6%, and 26.5% in patients with normal renal function, 9.6%, 17.6%, and 30.1% with moderate and 17.5%, 26.6%, and 31.9% in patients with severe RI (P = .77, by log-rank) at corresponding intervals. Multivariate analysis revealed eGFR (hazard ratio [HR], 1.016; 95% confidence interval [CI], 1.001-1.031; P = .036), age (HR, 1.12; 95% CI, 1.061-1.189; P < .0001) and cigarette smoking (HR, 3.14; 95% CI, 1.153-8.55; P = .026) to be predictors for increased mortality within 1 year of follow-up.

Conclusion: While functional lower limb outcomes were not influenced by renal function in this study, presence of RI was an independent predictor for higher mortality in CLI patients undergoing endovascular revascularization.