ASTRAL Findings Published

November 12, 2009—In the New England Journal of Medicine, the ASTRAL (Angioplasty and Stenting for Renal Artery Lesion) investigators have published findings from their study of revascularization versus medical therapy for renal-artery stenosis (2009;361:1953–1962).The background of the study is that percutaneous revascularization of the renal arteries improves patency in atherosclerotic renovascular disease, but evidence of a clinical benefit is limited.

According to the investigators, the randomized, unblinded trial assigned 806 patients with atherosclerotic renovascular disease either to undergo revascularization in addition to receiving medical therapy or to receive medical therapy alone. The primary outcome was renal function, as measured by the reciprocal of the serum creatinine level (a measure that has a linear relationship with creatinine clearance). Secondary outcomes were blood pressure, the time to renal and major cardiovascular events, and mortality. The median follow- up was 34 months.

The investigators reported that during a 5-year period, the rate of progression of renal impairment (as shown by the slope of the reciprocal of the serum creatininelevel) was –0.07 X 10^–3 L/µmol/year in the revascularization group, as compared with –0.13 X 10^–3 L/µmol/year in the medical-therapy group, a difference favoring revascularization of 0.06 X 10^–3 L/µmol/year (95% confidence interval [CI], –0.002 to 0.13; P = .06). Over the same time, the mean serum creatinine level was 1.6 µmol/L (95% CI, –8.4 to 5.2 [0.02 mg/dL; 95% CI, –0.10 to 0.06]) lower in the revascularizationgroup than in the medical-therapy group. There was no significant between-group difference in systolic blood pressure; the decrease in diastolic blood pressure was smaller in the revascularization group than in the medical-therapy group. The two study groups had similar rates of renal events (hazard ratio [HR] in the revascularization group, 0.97; 95% CI, 0.67–1.40; P = .88), major cardiovascular events (HR, 0.94; 95% CI, 0.75–1.19; P = .61), and death (HR, 0.90; 95% CI, 0.69–1.18; P = .46). Serious complications associatedwith revascularization occurred in 23 patients, including two deaths and three amputations of toes or limbs.

The investigators concluded that there are substantial risks but no evidence of a worthwhile clinical benefit from revascularization in patients with atheroscleroticrenovascular disease. However, the trial has been criticized in the endovascular community. Michael R. Jaff, DO, provides some counterpoints to the ASTRALinvestigators methods and findings in the sidebar on the previous page.