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Practice guidelines from 2005 recommended revascularization of renal artery stenoses for a wide range of patients with cardiovascular or renal sequelae (JW Cardiol Mar 23 2006). Performing this procedure seemed logical: Theoretically, opening and stenting the artery should prevent the clinical consequences of reduced renal blood flow. In 2009, two randomized trials provided evidence that countered predictions based on pathophysiology and expert opinion–based guidelines.
In one trial, researchers compared stents with medical management alone in 140 people with renal insufficiency and ≥50% stenosis (about half bilateral). The procedure was not associated with a significant reduction in a prespecified (≥20%) 2-year decline in renal function, and four serious adverse events occurred in the stent group (JW Gen Med Jul 21 2009).
Another randomized trial had a much larger enrollment — 806 patients with renal artery stenosis (800 had ≥50% stenosis) and related clinical findings. No significant improvements were noted in renal dysfunction, blood pressure, or adverse cardiovascular events in either the stent group or the medical group. No subgroup (defined by stenosis or renal dysfunction severity) benefitted. Twenty-three patients suffered serious complications related to revascularization (JW Gen Med Nov 12 2009).
In both trials, benefits were essentially nonexistent, and risks were substantial. Some experts have raised methodological concerns, such as imprecise definitions of stenosis, failure to restrict samples to those with clinically significant lesions, crossovers from assigned treatments, and lack of quality-of-life measures, in the latest trials (N Engl J Med 2009 Nov 12; 361:1972). A multicenter trial, CORAL, which will be completed in 2011, should address some of these issues. But whether resolving these concerns will lead to identification of subgroups that benefit from revascularization is unknown. Thus, while we await results from the next trial, revascularization for atherosclerotic renal artery stenosis should not be performed routinely, except perhaps for patients with severe stenoses and adverse cardiovascular consequences (e.g., recurrent heart failure).