RAS is less common in African Americans than in white Americans. Such bruits have been described in one half to two thirds of patients with surgically proven renovascular hypertension. A precipitous drop in BP, acute deterioration in renal function in response to ACE inhibitor therapy, or both suggest possible RAS and warrant further workup. The predictive value of such tests is extremely operator dependent, however, so patients should be referred to experienced, high-volume centers for testing.
Renal arteriography is required for definitive diagnosis and presurgical evaluation.
The natural history of RAS is progressive arterial occlusion with loss of renal function. The treatment of choice is revascularization via angioplasty or surgery. Renal revascularization is seldom successful in curing hypertension in middle-aged or elderly patients with atherosclerotic RAS but is useful in improving the ease of BP control with medical therapy and in preserving renal function. For patients in whom revascularization is not possible, strict BP control should be attempted. Use of an ACE inhibitor, alone or in combination with a diuretic, is preferred, except in bilateral RAS, RAS in a solitary kidney, or unilateral RAS with severe parenchymal disease in the contralateral kidney.