Vascular Quality Initiative-based risk score for mortality within 3 years of revascularization for chronic...

The purpose of this study was to create a validated risk score for the outcome of mortality within 3 years of revascularization for chronic limb-threatening ischemia (CLTI) in end-stage renal disease (ESRD) patients on dialysis.

Querying the United States-based data in the Vascular Quality Initiative identified 38,144 patients with ESRD undergoing open surgical or endovascular revascularization for CLTI. Two-thirds and one-third of the patients were divided into a risk score creation testing cohort and a validation cohort, respectively. Time-dependent multivariable Cox regression was performed utilizing variables associated with the outcome in the univariable analysis (P < .05). Variables with a P value of ≤.05 in the multivariable regression were included in the risk score and weighted based on their respective regression beta-coefficients on a point scale. Variables with a beta-coefficient of <.2 were assigned 1 point; then, a point was added for each increase in beta-coefficient at .2 intervals. A total score was then established for each patient based on the individual prevalence of the significant covariates. The mean 3-year mortality rate at each risk score bundle was calculated. The risk score was then applied to the validation cohort, who were not utilized for risk score creation, and event rates were compared between the testing and validation cohorts.

Testing cohort multivariable significance toward the primary outcome was noted for (P < .01 for all): suprainguinal bypass procedure (hazard ratio [HR] reference); suprainguinal bypass in combination with infrainguinal artery bypass (HR, 1.86); body mass index (BMI) < 20 kg/m² (HR, 1.32); BMI > 35 kg/m² (protective HR, 0.873); advancing age with each decade over the age of 50 years (P < .001 at each decade); history (Hx) of coronary artery disease (CAD; HR, 1.09); Hx of CAD revascularization over 5 years ago (HR, 1.12); CAD revascularization less than 5 years ago (HR, 1.12); congestive heart failure (CHF) class I (HR, 1.20); CHF class II (HR, 1.25); CHF class III (HR, 1.41); CHF class IV (HR, 1.86); no medicines in chronic obstructive pulmonary disease (COPD) (HR, 1.10); medicine use in COPD (HR, 1.18); oxygen use in COPD (HR, 1.406); nursing home status (HR, 1.11); prior carotid endarterectomy or stenting (HR, 1.18); absence of preoperative statin (protective HR, 0.611); dual antiplatelet at post-procedure discharge (protective HR, 0.910); absence of post-procedure antiplatelet (HR, 1.67), statin (HR, 2.12), and angiotensin-converting enzyme inhibitor (HR, 1.26); Asian race (HR, 1.25); White race (HR, 1.28); and unidentified race (HR, 1.12). Race HR was calculated with reference to the Black race HR. The mortality rate markedly increased, with event rates of 25% at the risk scores of ≤0 that increased to a 3-year mortality rate over 90% at the total risk score of 17 and higher. The odds ratio of the event rate was statistically significant with each increase in the risk score bundle. Subanalysis of baseline statin and hypertension revealed the significant (P < .001) benefits of statin therapy and angiotensin-converting enzyme/angiotensin receptor blocker at post-revascularization discharge, regardless of preoperative statin status or baseline hypertension.

A novel validated risk score for mortality within 3 years of revascularization for CLTI in patients with ESRD was created. Key modifiable variables that significantly enhance survival are the postoperative utilization of statin, antiplatelet, and ACE inhibitor medications (irrespective of baseline hypertension).