Abstract and Introduction
Abstract
Atherosclerotic renal artery stenosis may manifest as progressive renal dysfunction, difficult-to-manage hypertension and cardiac disturbance syndromes. While dilating the stenotic lesion in the renal artery is a sound choice from a physiologic and anatomic standpoint, endovascular renal artery stent revascularization has not demonstrated clear clinical benefit for these patients. However, as optimal medical therapy has not been shown to halt the progression of atherosclerotic renal artery stenosis or to affect clinical outcomes sufficiently, these interventions are becoming more prevalent in the treatment of this condition. Furthermore, trials comparing medical and endovascular treatments have serious flaws, thereby fostering confusion regarding patient selection. Proponents of endovascular renal artery stent revascularization suggest that technical improvements in the procedure, coupled with better predictors about which patients may truly benefit from endovascular treatment, will yield superior results in the future.
Introduction
Atherosclerotic renal artery stenosis (ARAS) is common, found to affect 6.8% of elderly (>65 years of age) participants in the Cardiovascular Health Study. A retrospective analysis of 395 arteriograms noted a high prevalence of renal artery stenosis (RAS) associated with atherosclerotic disease in other vascular beds ranging from 33 to 70%. Prevalence in patients with peripheral artery disease was reported to be as high as 59%. An analysis of 434 patients with hypertension (HTN) who underwent serial renal artery duplex ultrasonography over 3 years noted a prevalence of 20.6%. In another retrospective study of 127 patients undergoing lower extremity arterial revascularization, 57 patients (44.9%) had RAS.
Current guidelines suggest that treatment of ARAS should be offered to symptomatic patients only. Patients with hemodynamically significant ARAS and otherwise unexplained cardiopulmonary disturbance syndromes, such as unstable angina, recurrent unexplained congestive heart failure or sudden unexplained pulmonary edema should be treated. A class IIb recommendation was assigned to treating patients with hemodynamically significant RAS and accelerated, resistant or malignant HTN, HTN with an unexplained unilateral atrophic kidney, and HTN with intolerance to medication. Other indications included progressive chronic kidney disease with bilateral RAS or RAS to a solitary functioning kidney. Despite these recommendations, there is controversy regarding which patients benefit from intervention, as not all patients respond favorably to such treatment. In addition, there is no accepted tool that is uniformly used in everyday practice to predict which patients will respond with improved blood pressure control and prevention of deterioration in renal function.