Renal insufficiency as a predictor of adverse events and mortality after renal artery stent placement

Background: Renal artery stenosis (RAS) is associated with substantial morbidity and mortality. This relationship is strongest in the presence of renal insufficiency (RI). The goal of this study is to assess the relationship between RI, mortality, and adverse events in the setting of renovascular disease. Methods: Two hundred sixty-one patients with significant RAS treated with endovascular stenting were followed up prospectively for 21+/-18 months (range, 0 to 85 months). Blood pressure (BP), renal function, medication use, and comorbidities were assessed. Death was verified through the Social Security Death Master Index File, and cause of death was derived from death certificates. Medical records of 230 subjects subsequently were reviewed to identify adverse cardiovascular and renal events. Results: Overall, 37% of patients experienced at least 1 adverse event postprocedure. Myocardial infarction (MI) and congestive heart failure (CHF) events increased with degree of baseline RI. Seventy-three deaths (28%) occurred postprocedure (range, 13 to 2,457 days). Baseline characteristics associated with mortality included advanced age, decreased use of beta-blockers, increased use of diuretics, increased serum creatinine (Cr) level, decreased Cr clearance (CrCl), bilateral stenoses or stenosis of a solitary kidney, history of CHF, and history of MI. Follow-up characteristics associated with mortality included lower systolic and diastolic BP, increased serum Cr level, and decreased CrCl. RI at baseline and follow-up remained associated with mortality after adjusting for other clinically and statistically significant variables. Patients in whom renal function improved after stenting appeared to show improved survival over those without improved renal function (45% versus 0% cumulative survival, P<0.05). Conclusion: In patients with RAS undergoing stent therapy, baseline RI is associated with an increased incidence of adverse events, as well as decreased survival, independent of other baseline clinical factors. Importantly, improvement in renal function appears to be associated with increased survival.