Background-The aim of this study was to determine the incidence of and the risk factors associated with progression of renal artery disease in individuals with atherosclerotic renal artery stenosis (ARAS). Methods and Results-Subjects with Ն1 ARAS were monitored with serial renal artery duplex scans. A total of 295 kidneys in 170 patients were monitored for a mean of 33 months. Overall, the cumulative incidence of ARAS progression was 35% at 3 years and 51% at 5 years. The 3-year cumulative incidence of renal artery disease progression stratified by baseline disease classification was 18%, 28%, and 49% for renal arteries initially classified as normal, Ͻ60% stenosis, and Ն60% stenosis, respectively (Pϭ0.03, log-rank test). There were only 9 renal artery occlusions during the study, all of which occurred in renal arteries having Ն60% stenosis at the examination before the detection of occlusion. A stepwise Cox proportional hazards model included 4 baseline factors that were significantly associated with the risk of renal artery disease progression during follow-up: systolic blood pressure Ն160 mm Hg (relative risk [RR]ϭ2.1; 95% CI, 1.2 to 3.5), diabetes mellitus (RRϭ2.0; 95% CI, 1.2 to 3.3), and high-grade (Ͼ60% stenosis or occlusion) disease in either the ipsilateral (RRϭ1.9; 95% CI, 1.2 to 3.0) or contralateral (RRϭ1.7; 95% CI, 1.0 to 2.8) renal artery. Conclusions-Although renal artery disease progression is a frequent occurrence, progression to total renal artery occlusion is not. The risk of renal artery disease progression is highest among individuals with preexisting high-grade stenosis in either renal artery, elevated systolic blood pressure, and diabetes mellitus. (Circulation. 1998;98:2866-2872.)

Purpose: Although the prevalence of renal artery stenosis in patients with peripheral arterial disease is in the range of 30% to 40%, the role of renal revascularization in patients without severe hypertension or kidney failure is controversial. Duplex scanning is a noninvasive technique that is ideally suited for screening and follow-up of renal artery disease. The purpose of this study was to document the natural history of renal artery stenosis in patients who were not candidates for immediate renal revascularization. Methods: Eighty-four patients with at least one abnormal renal artery detected by duplex scanning were recruited from patients being screened for renal artery stenosis. Of the 168 renal artery/kidney sides, 29 were excluded (15 prior interventions, 6 nondiagnostic duplex scans, 8 presumed nonatherosclerotic lesions), leaving 80 patients with 139 sides for the follow-up protocol. Renal arteries were classified as normal, less than 60% stenosis, 60% or greater stenosis, or occluded by use of previously validated criteria.Results: The study group included 36 men and 44 women with a mean age of 66 years who were monitored for a mean interval of 12.7 months. The initial status of the 139 renal arteries was normal in 36, less than 60% stenosis in 35, 60% or greater stenosis in 63, and occluded in 5. Although none of the initially normal renal arteries showed disease progression, the cumulative incidence of progression from less than 60% to 60% or greater renal artery stenosis was 23% ± 9% at 1 year and 42% ± 14% at 2 years. All four renal arteries that progressed to occlusion had 60% or greater stenoses at the initial visit, and for those sides with a 60% or greater stenosis, the cumulative incidence of progression to occlusion was 5% ± 3% at 1 year and 11% ± 6% at 2 years. The mean decrease in kidney length associated with progression of renal artery stenosis to occlusion was 1.8 cm. Conclusions: Progression of renal artery stenosis, as defined in this study, occurs at a rate of approximately 20% per year. Progression to occlusion is associated with a marked decrease in kidney length. Whether this natural history can be improved by earlier intervention for renal artery stenosis remains to be determined.

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The goal of this study was to determine the incidence of and risk factors for renal atrophy among kidneys with atherosclerotic renal artery stenosis (ARAS). Participants with at least one ARAS were followed prospectively with duplex scans performed every six months. Renal atrophy was defined as a reduction in renal length of greater than 1 cm. A total of 204 kidneys in 122 subjects were followed for a mean of 33 months. The two-year cumulative incidence (CI) of renal atrophy was 5.5%, 11.7%, and 20.8% in kidneys with a baseline renal artery disease classification of normal, <60% stenosis, and > or = 60% stenosis, respectively (P = 0.009, log rank test). Other baseline factors associated with a high risk of renal atrophy included a systolic blood pressure > 180 mm Hg (2-year CL = 35%, P = 0.01), a renal artery peak systolic velocity > 400 cm/second (2-year CI = 32%, P = 0.02), and a renal cortical end diastolic velocity < or = 5 cm/second (2-year CI = 29%, P = 0.046). The number of kidneys demonstrating atrophy per participant was correlated with elevations in the serum creatinine concentration (P = 0.03). In patients with ARAS, there is a significant risk of renal atrophy among kidneys exposed to elevated systolic blood pressure and among those with high-grade ARAS and low renal cortical blood flow velocity as assessed by renal duplex scanning. The occurrence of renal atrophy is well-correlated with changes in the serum creatinine concentration.