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Research funded by the Medical Research Council UK, Kidney Research UK and Medtronic has concluded that revascularisation, a treatment which opens up blocked blood vessels, has no benefit for most patients suffering from the kidney condition atherosclerotic renal artery stenosis (ARAS).

Atherosclerotic renal artery stenosis is a disease of the arteries in which fatty plaques develop on the inside of the main arteries to the kidneys affecting blood flow and the ability of the kidneys to work properly.

The “Angioplasty and Stenting for Renal Artery Lesions” (ASTRAL) trial is the largest trial to date into treatment for the kidney condition, It considered whether there is any real benefit to a combined approach of revascularisation treatment and medical therapy, compared with just medical therapy alone.  

The findings of the trial, published today in the New England Journal of Medicine (12 November 2009) suggest that using this procedure doesn’t stabilise or improve kidney function and that the risks of using the treatment may outweigh the benefits. 806 patients participated in the trial which opened to recruitment in September 2000 and closed in October 2007,

Professor Jon Moss, the radiology lead for the trial, said: “Revascularisation, which involves inserting a metallic stent (or tube) in the narrowed artery certainly increases the blood flow to the kidney and helps keep the artery open in the future.  The technique is widely used especially in coronary arteries to good effect.  However, the results from the ASTRAL trial suggest that, in most patients, using this procedure for renal artery stenosis does not stabilise or improve kidney function or blood pressure control, or reduce cardiovascular disease or mortality, more than medical therapy alone.  Given the risk of serious complications, it should be used less.”

Professor Phil Kalra, the nephrology lead for the trial, added: “Although ASTRAL shows that in the majority of patients’ revascularisation provides no clinical benefit, the study does not however, rule out the possibility that a small proportion of patients with renovascular disease may benefit from stenting, and we need more research to identify whether such patients exist.  What was also interesting is that there was an improvement in patients’ blood pressure during the ASTRAL trial, and kidney function declined slower than was expected in both groups, which suggests that medical treatment for renovascular disease has got better over the years, which is good news.”

Professor Keith Wheatley, who led the research at the University of Birmingham Clinical Trials Unit, said: “This study clearly illustrates that patients with renal artery stenosis remain at high risk.  During the course of the trial, a number of patients developed end-stage renal disease and needed dialysis, or had a heart attack or stroke, and almost half of the patients had died by five years.  Therefore, more research is needed in this disease area to find more effective treatments.”

Dr Morven Roberts, Medical Research Council Programme Manager, said:  “Until now, a question mark has hung over whether revascularisation treatment for this condition really helps patients. Although the ASTRAL trial shows this treatment isn’t a panacea for this condition, it does establish that current clinical practices are the best on offer to date.”

The ASTRAL trial was an international, randomised clinical trial designed and conducted by researchers in the United Kingdom and Australasia, and was co-coordinated by the University of Birmingham Clinical Trials Unit.