Implications of Acute Functional Injury following Percutaneous Renal Artery Intervention

Percutaneous renal artery revascularization for hypertension and renal dysfunction is now common, and there is an increasing realization that renal artery intervention can be associated with parenchymal injury. The frequency, cause, and outcomes of acute functional injury associated with renal intervention are poorly delineated. Our aim was to determine the frequency of acute functional renal injury 30 days after renal artery intervention, to identify factors associated with functional renal injury and determine whether functional renal injury related to renal intervention is associated with late adverse clinical events. A retrospective analysis of patients undergoing renal artery interventions for atherosclerotic renal artery disease between 1990 and 2007 was performed. No distal embolic protection devices were used. Acute functional parenchymal renal injury was defined as a persistent increase in serum creatinine of >= 0.5mg/dL at 1 month after the procedure. Freedom from kidney-related morbidity (increase in persistent creatinine > 20% of baseline, progression to hemodialysis, death from kidney-related causes) and patient survival were measured. There were 418 patients who underwent 581 renal artery interventions: 57% for hypertension, 23% for hypertension associated with chronic renal insufficiency, and 12% for renal insufficiency. Acute functional renal injury occurred in 20% of the patients. The occurrence of a functional injury was associated with a significant decrement in freedom from kidney-related morbidity (mean +/- SEM 80 +/- 2% vs. 55 +/- 10%, no injury vs. injury, p < 0.01) and markedly decreased survival at 5-year follow-up (71 +/- 4% vs. 41 +/- 10%, p < 0.01). At 5-year follow-up, three times as many patients with functional injury progressed to hemodialysis compared to those without injury (19% vs. 7%, p < 0.01). By multivariate analysis, the presence of an unrepaired abdominal aortic aneurysm (AAA), low estimated glomerular filtration rate, non-insulin-dependent diabetes mellitus, contralateral renal artery disease, and a solitary kidney were significantly associated with functional injury and poor long-term clinical benefit. Hypertension, hyperlipidemia, and contrast volume were determined to be not significant. Acute functional renal injury occurs in approximately 20% of patients undergoing percutaneous renal artery intervention and is more likely in the presence of an unrepaired AAA, non-insulin-dependent diabetes mellitus, and preexisting renal disease. Acute functional renal injury is a negative predictor of survival and is associated with subsequent renal failure, need for dialysis, and death. While this data set does not establish a causal relationship, patients who are predisposed to acute functional injury may have underlying factors that also lead to decreased long-term renal function and decreased survival.