A prospective study of disease progression in patients with atherosclerotic renal artery stenosis

The natural history of renal artery stenosis (RAS) has been difficult to document because serial arteriography is rarely justified. Duplex scanning is a noninvasive technique that is ideally suited for both screening and follow-up of RAS. In this approach, renal arteries are classified as normal, < 60% stenosis, > or = 60% stenosis, or occluded, and disease progression is defined as a change in the duplex classification. The purpose of this study was to determine the rate of disease progression in atherosclerotic RAS by serial duplex scanning. At least one abnormal renal artery was identified in each of 76 patients being screened for RAS. Of the 152 renal arteries, 20 were excluded (14 prior interventions, 5 occlusions, 1 technically inadequate duplex scan), leaving 132 for the natural history follow-up protocol. The patient group included 36 men and 40 women, with a mean age of 67 years, who were followed for a mean of 32 months (maximum 55 months). The initial status of the 132 renal arteries was normal in 36, < 60% stenosis in 35, and > or = 60% stenosis in 61. The cumulative incidence of progression from normal to > or = 60% RAS was 0% at 1 year, 0% at 2 years, and 8% at 3 years. The cumulative incidence of progression from < 60% to > or = 60% RAS was 30% at 1 year, 44% at 2 years, and 48% at 3 years. All 4 renal arteries that progressed to occlusion had > or = 60% stenoses at the initial visit, and for those arteries with a > or = 60% stenosis, the cumulative incidence of progression to occlusion was 4% at 1 year, 4% at 2 years, and 7% at 3 years. Progression of RAS occurred at an average rate of 7% per year for all categories of baseline disease combined. Progression of atherosclerotic RAS is relatively common, particularly from < 60% to > or = 60% stenosis.