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The impact of renal artery revascularisation in atherosclerotic renovascular disease: the Angioplasty and Stenting for Renal Artery Lesions (ASTRAL) trial

Philip A Kalra and on behalf of the ASTRAL Collaborative Group
Department of Renal Medicine, Salford Royal Hospitals Foundation Trust, Manchester, United Kingdom; MAY MAY MAY 13th - SYMPOSIUM 29 - HALL A4/5 11:30 - 12:30
 
INTRODUCTION AND AIMS: Outcomes after percutaneous renal revascularization in atherosclerotic renovascular disease (ARVD) have been uncertain and the results of adequately powered randomised control trials (RCT) are needed.
METHODS: The Angioplasty and Stenting for Renal Artery Lesions (ASTRAL) trial randomised patients equally between percutaneous revascularization (angioplasty and/or stenting) plus medical therapy versus medical therapy alone. Entry criteria were ARVD patients in whom clinicians were substantially uncertain whether to recommend revascularization, and no prior revascularization. The primary end point was rate of decline of renal function as assessed by reciprocal serum creatinine over time. Secondary endpoints were blood pressure control, occurrence of renal events (e.g. acute renal failure, dialysis), serious vascular events and mortality. The trial had broad eligibility criteria so that these outcomes could be investigated in a clinically relevant population.
RESULTS: Between November 2000 and October 2007, ASTRAL recruited 806 ARVD patients from 56 centres (52 UK based and 4 in Australasia), making it over 7 times larger than any previous RCT in ARVD. Baseline data for the whole group at randomisation were mean age (range) of patients 70 years (42 - 88), 63% male, serum creatinine 179 mmol/l (64 - 750), estimated GFR 40ml/min (5.4 -124.5) and blood pressure 151/76 mm Hg (87/45 - 270/130). 54% of patients were ex-smokers, 30% were diabetic and 49%, 40% and 19% had a previous history of coronary heart disease, peripheral vascular disease and stroke, respectively. 80% were treated with statins, 90% anti-platelet drugs and 98% were receiving antihypertensive therapy. At the time of first analysis in March 2008, mean follow up was 27 months. Average renal artery stenosis (RAS) at entry was 76% and 4 year mortality was 34%. Results were adequately powered at the 12 month follow up point at which stage there was no difference in renal function (creatinine increased by 18 mmol/l in both groups), systolic (decrease by 5 mmHg in both) or diastolic blood pressure, combined renal events and combined cardiovascular events (including death) between the two arms of the trial. At 4 years follow up there was a slight benefit in favour of revascularization for creatinine (10 mmol/l difference), systolic blood pressure, combined renal (17% vs. 23%) and cardiovascular events (34% vs. 41%), but the data was underpowered to be conclusive at this stage.
CONCLUSIONS: ASTRAL is by far the largest randomised trial in ARVD. Initial analysis has shown that in patients with a range of radiologically significant RAS lesions, there was no benefit in any outcome measure from additional revascularization when both groups were treated with optimal medical therapy.