We separated the patients into two groups by indication for RDS: Group I (HT alone, n = 102) and group II (RF alone or with HT, n = 112). When group I was compared with group II, there were significant differences in gender (50% vs 67% male; P = .013), age (50.9 ± 18.5 vs 60.0 ± 14.8 years; P < .001), mean arterial pressure (103.1 ± 18.8 vs 85.7 ± 17.0 mm Hg; P < .001), and creatinine (0.95 ± 0.35 vs 2.25 ± 1.07 mg/dL; P < .001). In group I patients, 86 (84.3%) had normal parenchymal resistance, whereas in group II patients, 68 (60.7%) had abnormally increased parenchymal resistance unilaterally or bilaterally (P < .001). Unilateral or bilateral renal artery stenosis was identified in six group I patients and in three group II patients (P = .315). Evaluation of group II patients revealed a diagnosis of decompensated congestive heart failure (CHF) and the presence of unilateral or bilateral increased parenchymal resistance in 27 of 68 (39.7%) vs nine of 44 (20.4%) with CHF and normal parenchymal resistance. One renal artery angioplasty was performed in a patient with unilateral renal artery stenosis and fibromuscular dysplasia.