RADAR – A randomised, multi-centre, prospective study comparing best medical treatment versus best medical treatment plus renal artery stenting in patients with haemodynamically relevant atherosclerotic renal artery stenosis

BACKGROUND: Prospective, international, multi-centre, randomised (1:1) trial to evaluate the clinical impact of percutaneous transluminal renal artery stenting (PTRAS) on the impaired renal function measured by the estimated glomerular filtration rate (eGFR) in patients with haemodynamically significant atherosclerotic renal artery stenosis. METHODS: Patients will be randomised to receive either PTRAS using the Dynamic Renal Stent system plus best medical treatment or best medical treatment. Renal stenting will be performed under angiographic imaging. For patients randomised to best medical treatment the degree of stenosis measured by renal duplex sonography (RDS) will be confirmed by MR angio or multi-slice CT where possible. Best medical treatment will be initiated at randomisation or post procedure (for PTRAS arm only), and adjusted as needed at all visits. Best medical treatment is defined as optimal drug therapy for control of the major risk factors (blood pressure ≤ 125/80 mmHg, LDL cholesterol ≤ 100 mg/dL, HbA1c ≤ 6.5%). Data recordings include serum creatinine values, eGFR, brain natriuretic peptide, patients' medical history and concomitant medication, clinical events, quality of life questionnaire (SF-12v2™), 24 hour ambulatory blood pressure measurement, renal artery duplex ultrasound and echocardiography. Follow-up intervals are at 2, 6, 12 and 36 months following randomisation. The primary endpoint is the difference between treatments in change of eGFR over 12 months. Major secondary endpoints are technical success, change of renal function based on the eGFR slope change between pre-treatment and post-treatment (i.e. improvement, stabilisation, failure), clinical events overall such as renal or cardiac death, stroke, myocardial infarction, hospitalisation for congestive heart failure, progressive renal insufficiency (i.e. need for dialysis), need of target vessel revascularisation or target lesion revascularisation, change in average systolic and diastolic blood pressure, change in left ventricular mass index calculated from echocardiography, difference in the size of kidney (pole to pole length) measured by renal duplex sonography, total number, drug name, drug class, daily dose, regimen and Defined Daily Dose (DDD), of anti-hypertensive drugs, and change in New York Heart Association (NYHA) classification. Approximately 30 centres in Europe and South America will enrol patients. Duration of enrolment is expected to be 12 months resulting in study duration of 48 months. TRIAL REGISTRATION: Trial registration number: NCT00640406