Impact of Dialysis Vintage and Renal Biomarkers on Mortality in Dialysis-Dependent Patients With Critical Limb Ischemia Undergoing Revascularization

Abstract

Purpose: Revascularization of both endovascular therapy (EVT) and surgical reconstruction improve clinical outcomes of patients with critical limb ischemia (CLI); however, treatment of dialysis-dependent patients with CLI is still challenging. This study aimed to investigate the impact of dialysis-related parameters on the risk of mortality in dialysis-dependent patients undergoing revascularization for CLI. Materials and Methods: We retrospectively identified 274 dialysis-dependent patients with CLI (196 males; mean age 71 years), who underwent revascularization, from the clinical database of the surgical reconstruction vs peripheral intervention in patients with critical limb ischemia (SPINACH) study, which was a prospective, multicenter, observational study. Of these patients, 175 patients underwent EVT and 99 patients received surgical reconstruction. The current study evaluated the impact of dialysis vintage and renal biomarkers on the mortality rate of dialysis-dependent patients with CLI undergoing revascularization. Results: During a mean follow-up period of 1.7 ± 1.1 years, 147 deaths were observed. The 3-year overall survival rate and its standard error were estimated to be 40.5% ± 8.1% using the Kaplan-Meier method. A Cox proportional hazard analysis revealed that dialysis vintage ≥4 years, serum creatinine levels <4.7 mg/dL, serum urea nitrogen ≥88 mg/dL, and calcium-phosphate product ≥62.6 mg2/dL2 were independent risk factors for mortality after adjustment for the detailed mortality risk score developed in the SPINACH study. Adding these parameters to the original mortality risk score slightly, but not significantly, increased the area under the time-dependent receiver operating characteristics curve from 0.74 (95% CI, 0.67 to 0.81) to 0.77 (0.71 to 0.84) (p=0.084), whereas continuous net reclassification improvement reached 0.75 (0.12 to 0.90) (p=0.027). Conclusion: We found that long dialysis vintage, low serum creatinine, high serum urea nitrogen, and high calcium-phosphate product were independently associated with the increased risk of mortality in dialysis-dependent patients with CLI undergoing revascularization.