Randomization and Interventions
We assigned participants, in a 1:1 ratio, to either medical therapy alone or stenting plus medical therapy. Randomization was performed by means of an interactive voice randomization system with the use of a permuted block design. All participants in both treatment groups received antiplatelet therapy and other protocol-driven medical therapies to control blood pressure and glucose and lipid levels in accordance with guidelines.19,20
Unless otherwise contraindicated, the following medications were mandated by the protocol: the angiotensin II type-1 receptor blocker candesartan (Atacand, AstraZeneca), with or without hydrochlorothiazide, and the combination agent amlodipine–atorvastatin (Caduet, Pfizer), with the dose adjusted on the basis of blood pressure and lipid status. Participants received voucher cards that allowed them to obtain the medications (candesartan, hydrochlorothiazide, and atorvastatin–amlodipine) from their local pharmacies at no personal cost. The target blood pressure was less than 140/90 mm Hg in patients without coexisting conditions and less than 130/80 mm Hg in patients with diabetes or chronic kidney disease. Medications were adjusted until the blood-pressure goal was reached.17 Blood pressure was measured three times, 2 minutes apart, in each participant, with the use of an oscillometric device. The measurements were made while participants were sitting quietly, and the mean of the last two measurements was used.
Participants in the stent group underwent placement of a Palmaz Genesis stent (Cordis); predilation was performed at the discretion of the investigator. All renal arteries with stenoses of 60% or more were treated. In patients with multiple stenoses, stenting could be performed as a single procedure or in intervals of 2 to 4 weeks. Before August 2006, the use of the short-tip Angioguard device was required for embolic protection; after this date, an embolic protection device approved by the Food and Drug Administration (FDA) was used at the operator's discretion.
Crossovers from the medical therapy group to the stent group were reviewed by a designated crossover committee. Crossovers were not approved unless a qualifying outcome event had occurred or all of the following conditions were met: acute anuric renal failure, complete occlusion of all renal arteries, and at least one kidney more than 8 cm in length.