Is Renal Artery Stenting the Correct Treatmentof Renal Artery Stenosis?

Abstract

The case favoring renal artery stenting for individuals with renal artery hypertension is largely circumstantial. At best, the clinical evidence presented in this discussion is derived primarily from nonrandomized cohort studies. It would certainly be easier to argue that medical therapy is preferred for such individuals because there are 3 published randomized clinical trials that concluded just that and none that support renal artery intervention. Nonetheless, there is considerable evidence to support the role for revascularization in general, and stenting specifically, as an important adjunctive therapy to medical therapy in the care of patients with renal artery stenosis (RAS). The argument has 3 principal components: observations about the impact on cardiovascular physiology, end-organ effects, and natural history. Response by Dworkin and Jamerson p 270 RAS is associated with and is an important cause of secondary hypertension. RAS causes endocrine activation with release of renin from renal juxtaglomerular cells. Renin catalyzes the breakdown of angiotensinogen to angiotensin I. Angiotensin I is transformed by angiotensin-converting enzyme into angiotensin II, and angiotensin II promotes the release of aldosterone from the adrenal cortex.1 Angiotensin II is a potent vasoconstrictor,2 substantially more potent than epinephrine, and is implicated in end-organ damage in the heart3 and kidney.4 RAS is suggested to cause 2 types of hypertension. With unilateral RAS and a normally perfused and normally functioning contralateral kidney, blood pressure elevation is referred to as “renin dependent” and is characterized by increased peripheral resistance.5,6 In this circumstance, renin and angiotensin levels remain elevated, but volume expansion is limited by natriuresis of the contralateral normally functioning kidney.6 Importantly, although renin levels are elevated, the value of peripheral or even renal vein renin values is limited by substantial overlap with patients having essential hypertension.7,8 When stenoses are bilateral or when the …