Renovascular Hypertension With Renal Failure

The goal of this clinical trial is to document a beneficial effect of percutaneous transluminal renal angioplasty (PTRA) of atherosclerotic renal artery stenosis in high-risk patients selected according to the criteria used in the DAN-PTRA study. The main questions the trial aims to answer are if renal artery stenting compared with optimal medical treatment alone has beneficial effects on: * Blood pressure * Kidney function * Hospitalizations for heart failure