Operative mortality for renal artery bypass in the United States: Results from the National Inpatient Sample

Abstract

Background: The mortality rate for renal artery bypass grafting (RABG) is reported to be 0% to 4% for patients with renovascular hypertension and 4% to 7% for patients with ischemic nephropathy. However, these data come from high-volume referral centers known for their expertise in treating these conditions. Because of the relative infrequency of these operations in most vascular surgery practices, the nationwide outcomes for RABG are not known. The purpose of this study was to define the operative mortality rate for RABG in the United States and to identify risk factors for perioperative mortality.

Methods: The National Inpatient Sample was analyzed to identify patients undergoing RABG for the years 2000 to 2004. Categoric data were analyzed using chi(2) and the Cochran-Armitage trend tests. Multivariate logistic regression analyses were performed to identify risk factors for perioperative mortality after RABG.

Results: During the study period, 6608 patients underwent RABG, representing a frequency of 3.51 operations per 100,000 discharges. More than two-thirds were performed at teaching hospitals (4564 vs 2,044; P < .0001). The frequency of RABG decreased by 30.7% between 2000 and 2004 (4.28 vs 2.96 RABGs per 100,000 discharges; P for trend < .0001). The in-hospital mortality for RABG was 10.0%. On univariate analysis, in-hospital mortality after RABG varied with increasing age, race, region of the country, and a preoperative history of chronic renal failure, congestive heart failure, or chronic lung disease. Logistic regression models identified advanced age (odds ratio [OR] 1.57; 95% confidence interval [CI], 1.44-1.72], female gender (OR, 1.20; 95% CI, 1.02-1.41), and a history of chronic renal failure (OR, 2.21; 95% CI, 1.75-2.78), congestive heart failure (OR, 1.94; 95% CI, 1.44-2.62), or chronic lung disease (OR, 1.40; 95% CI, 1.18-1.67) as independent markers of risk-adjusted, in-hospital mortality (P < .0001 for each of these five variables).

Conclusions: Nationwide in-hospital mortality after RABG is higher than predicted by prior reports from high-volume referral centers. Advanced age, female gender, and a history of chronic renal failure, congestive heart failure, or chronic lung disease were predictive of perioperative death. For the typical vascular practice, these data may provide a rationale for lower risk alternatives, such as renal artery stenting or referral to high-volume referral centers for RABG.