When stenting in renal artery stenosis? Update on pathophysiology of ischemic nephropathy and management strategies

In recent years, decisions taken on the optimal management of patients with renal artery stenosis have triggered off controversy and debate among clinicians dealing with renovascular disease. The main reason underlying this ongoing controversy may be the heterogeneity of the clinical entities that are normally associated with the umbrella definition of renal artery stenosis. Indeed a causal link between the stenosis and its clinical consequences (i.e. hypertension, renal failure) can often demonstrated in some entities, such as fibromuscular dysplasia, truncal stenosis or arterial stenosis in the transplanted kidney, which can be defined as pure renal artery stenosis. On the contrary, the entity generally called ostial stenosis is a disease of the abdominal aorta where it encroaches the ostium of the renal artery at the end of a long process involving the entire vascular tree. Patients affected by ostial stenosis also suffer from generalized atherosclerosis, and kidney damage is often caused by the atherosclerotic environment with the stenosis acting as an innocent bystander. This may account for the low rate of renal function recovery in subjects with ostial stenosis. In our view, keeping the different entities separate along with a careful understanding of the mechanisms underpinning renal damage, particularly the intrarenal activation of the renin angiotensin system which in turn induces renal inflammation and oxidative stress, may enable clinicians to make the right decisions in regard to revascularization.