Introduction: Patients undergoing endovascular therapy (EVT) for lower extremity peripheral arterial disease (PAD) are at risk for acute kidney injury (AKI). The purpose of this study was to determine the incidence, risk factors, and outcomes of AKI in the context of EVT from the National Inpatient Sample (NIS).
Methods: Patient admissions in the NIS were queried from 2003-2012. The admissions were limited to non-dialysis patients with either critical limb ischemia (CLI) or claudication undergoing either EVT and/or angiography. AKI was defined using a composite of ICD-9 codes which have been previously validated in this context. Available comorbidity data, demographics, and inpatient outcomes (AKI, mortality) were analyzed using multivariable logistic regression models with age expressed in decades.
Results: 552,484 admissions for CLI and 441,736 for claudication were included. The incidence of AKI is shown in the figure. The multivariate predictors of AKI in patients with claudication undergoing EVT only included age (OR 1.05, CI [1.02-1.09], P<0.001), female gender (OR 1.1, CI [1.01-1.15], P=0.03), heart failure (OR 2.8, CI [2.6-3.1], P<0.001), chronic kidney disease (CKD) (OR 6.5, CI [6.0-7.1], P<0.001), and diabetes (OR 1.1, CI [1.05-1.2], P=0.001). A similar analysis for CLI patients revealed the following predictors: age (OR 1.1, CI [1.09-1.12], P<0.001), heart failure (OR 2.1, CI [2.05-2.22], P<0.001), CKD (OR 2.8, CI [2.7-2.9], P<0.001), diabetes (OR 1.2, CI [1.1-1.2], P<0.001), and stroke (OR 1.6, CI [1.45-1.7], P<0.001). AKI was an independent predictor of mortality in patients undergoing EVT with either claudication (OR 17.8 [15.5, 20.5], P<0.001) or CLI (OR 4.6 [4.2, 4.9], P<0.001).
Conclusions: AKI occurs in approximately 3.5% of patients undergoing endovascular procedures for claudication and 10.9% in CLI patients. CKD and heart failure are the strongest risk factors for AKI. AKI is an independent predictor of inpatient mortality.