Background: Renal artery stenosis (RAS) is a relatively uncommon but potentially reversible cause of renal failure. In a previous report, we demonstrated that the presence of RAS is independently associated with mortality in a group of patients undergoing coronary angiography. Our current study expands on this cohort, investigating the effect of the severity of RAS on all-cause mortality.
Methods: A total of 3987 patients underwent abdominal aortography immediately following coronary angiography. For the purpose of survival analysis, significant RAS was defined as > or =75% narrowing in the luminal diameter.
Results: Significant RAS was present in 4.8% of patients studied and was bilateral in 0.8%. Factors associated with the presence of RAS included female gender, older age, hypertension, congestive heart failure, elevated serum creatinine, and congestive heart failure. The four-year unadjusted survivals for patients with and without significant RAS were 57 and 89%, respectively (P < 0.001). Using the Cox proportional hazards model, the factors independently associated with decreased survival were the presence of RAS, increased age, the severity of coronary artery disease, the presence of comorbid disease, reduced ejection fraction, symptoms of congestive cardiac failure, and the mode of treatment of coronary artery disease. In the multivariate model, the presence of RAS conferred a hazard ratio of 2.01 (95% CI, 1.51 to 2.67, P < 0.001). We demonstrated an incremental effect on mortality according to the severity of RAS at baseline. Four-year adjusted survival for patients with 50%, 75%, and > or =95% stenosis was 70%, 68%, and 48%, respectively. In addition, bilateral disease was associated with four-year survival of 47% as compared with 59% for patients with unilateral disease (P < 0.001). The impact of RAS on survival remained robust regardless of the manner of treatment of coronary artery disease [that is, medical, percutaneous transluminal coronary angioplasty (PTCA), or coronary artery bypass graft (CABG)].
Conclusions: In this patient population, the presence of RAS is a strong independent predictor of mortality. Increasing severity of RAS has an incremental effect on survival probability.