2007 Charles T. Dotter Memorial Lecture—Renal Artery Stenosis and Cardiovascular Risks—The New Paradigms in Diagnosis and Treatment
Renal artery stenosis (RAS), hypertension, and renal insufficiency are each frequently present especially in the elderly population. RAS is often present without any clinical signs or symptoms, and even when hypertension or renal insufficiency is also present, these conditions may be coincidental rather than causally related. However, when RAS is physiologically significant (10% peak systolic trans-stenotic pressure gradient), it is one of the few potentially reversible causes of renal insufficiency and hypertension.
RVH is mediated by angiotensin II, a powerful vaso-constrictor producing systemic hypertension, cellular hypertrophy, proliferation of vascular smooth muscle cells, vascular and left ventricular hypertrophy, accelerated atherosclerosis, and progressive glomerular sclerosis, independent of the level of hypertension. Physiologically significant RAS also has direct effects on sympathetic nerve activity, nitric oxide production, and intrarenal prostaglandin concentration. Patients with atheromatous RAS (ARAS) and end-stage renal disease have a significantly higher mortality rate than the general dialysis population.
Some advocate prophylactic intervention for asymptomatic and hemodynamically insignificant ARAS; however, ARAS is a marker for but not an independent risk factor for major adverse cardiac events. Aggressive statin therapy arrests progression and produces regression of coronary and carotid atheroma.
Patients with asymptomatic and hemodynamically nonsignificant ARAS should be treated with aggressive statin and glucose control therapy, aspirin, and lifestyle modifications. This would likely produce all the potential benefits of prophylactic stenting, the very long-term durability and fate of which are unknown, and without any of its known major risks such as cholesterol embolisation and the 15% to 20% restenosis that can occur even in “low-risk” patients.
In summary, appropriately selected patients with ARAS and renal insufficiency benefit from interventional therapy, whereas those with clinically and hemodynamically nonsignificant stenoses should be treated by aggressive medical therapy, including statins and life style modifications.