A new study in the New England Journal of Medicine reports that, compared with usual care, percutaneous revascularization did not improve outcomes in patients with asymptomatic renal artery stenosis. However, a large number of patients in the trial had only mild to moderate blockage that would not typically be treated with stenting.

The ASTRAL (Angioplasty and Stenting for Renal Artery Lesions) was a multicenter international trial that recruited patients with renal artery stenosis and related clinical findings such as uncontrolled hypertension or unexplained renal dysfunction. In all cases, the treating physicians were not sure where revascularization would confer clinical benefit. The patients were then randomized to medical therapy plus revascularization (with or without stenting; n=403) or medical therapy alone (statins, antiplatelets, and blood pressure control; n=403). In the revascularization group, 83% of the patients underwent revascularization (n=335) due primarily to a stenosis less extensive than expected. The primary outcome measure was renal function; secondary outcomes were blood pressure, the time to renal and major cardiovascular events, and mortality. Mean follow-up was 34 months.

Through a median follow-up of 34 months, the primary endpoint did not differ significantly between the two groups (P=0.06). There were no differences in the occurrence of renal or major cardiovascular events or death (all; P>0.05). The only secondary outcome that differed between the two groups was diastolic blood pressure, which was significantly lower in the medical management group (P=0.03). In total, there were 31 serious complications from revascularization in 23 patients and 2 deaths. Of note is that a subgroup analysis of high-risk patients (bilateral stenosis > 70% or stenosis > 70% in a single functioning kidney) versus low-risk patients also failed to show any significant difference in outcomes following revascularization.

The most important limitation of this study is the inclusion of only asymptomatic patients without clear indications for revascularization. Therefore, the applicability of these results to patients with more severe stenosis is unclear. Data from the CORAL (Cardiovascular Outcomes in Renal Atherosclerotic Lesions) trial, a larger study sponsored by the National Institutes of Health (NIH), may provide more evidence as to the most advantageous approach to patient selection and optimal treatment.

1. ASTRAL Investigators. Revascularization versus medical therapy for renal-artery stenosis. N Engl M Med. 2009;361(20):1953-1962. Abstract available at: http://content.nejm.org/cgi/content/short/361/20/1953. Accessed December 2, 2009.

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This entry was posted on Wednesday, December 2nd, 2009 at 12:00 pm.