Conclusions and Perspectives. The METRAS Study has been designed to provide a conclusive answer to a very debated question: is angioplasty combined with stenting and associated with optimal medical therapy equivalent to the optimal medical treatment alone in preventing deterioration of renal function, assessed as GFR in the ischemic kidney? A novel approach, consisting in evaluating deterioration of renal function, as assessed as GFR in the ischemic kidney, rather than the overall GFR, will clarify if PTRAS can protect a kidney with stenotic artery from functional declining.