title: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Swiss Cardiovascular Center, Clinical and Interventional Angiology, Bern, Switzerland.
authors.forename: Torsten
authors.initials: T
authors.lastname: Willenberg
authors.forename: Frederic
authors.initials: F
authors.lastname: Baumann
authors.forename: Ute
authors.initials: U
authors.lastname: Eisenberger
authors.forename: Iris
authors.initials: I
authors.lastname: Baumgartner
authors.forename: Dai-Do
authors.initials: DD
authors.lastname: Do
authors.forename: Nicolas
authors.initials: N
authors.lastname: Diehm
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007511:Ischemia / Q000503:physiopathology* / Q000601:surgery*; D035002:Lower Extremity / Q000098:blood supply* / Q000601:surgery; D008297:Male; D051437:Renal Insufficiency / Q000503:physiopathology*; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures