Atherosclerotic renovascular disease: Medical therapy versus medical therapy plus renal artery stenting in preventing renal failure progression. The rationale and study design of a prospective, multicenter and randomized trial (NITER)

Background: Many studies suggest a major prevalence of atherosclerotic renovascular disease (ARVD), caused by mono or bilateral renal artery stenosis (RAS). Unfortunately, there is no definite therapy to cure this disease to date; therefore, ARVD is burdened by important clinical complications with high social and economic costs. The last few years have seen important advancements in both medical therapy and in interventional radiology (for example, percutaneous transluminal renal artery stenting (PTRS)). All of them could affect, in some way, the natural history of ARVD, but to date the optimal strategy has not been established. Methods: The protocol of a prospective, multicenter, randomized trial "Nephropathy Ischemic ThERapy (NITER)" is presented. It enrolls patients with stable renal failure (glomerular filtration rate (GFR) ≥30 ml/min) and hyper- tension, and hemodynamically significant atherosclerotic ostial RAS (≥70%) diagnosed by duplex Doppler (DD) ul- trasonography and confirmed by magnetic resonance angiography (MRA). This study aims to evaluate whether med- ical therapy plus interventional PTRS is superior to medical therapy alone according to the following combined pri- mary endpoint: death or dialysis initiation or reduction by >20% in estimated GFR after 0.5, 1, and 2 yrs of follow-up and an extended follow-up until the 4th year. Medical therapy means drugs to control hypertension, improve dyslipi- demia and optimize platelet anti-aggregant therapy. The sample size is estimated in 50 patients per group to achieve a statistical significance of 0.05 in case of a reduction by 50% in the combined endpoints.