Medical and Endovascular Treatment of Atherosclerotic Renal Artery Stenosis (METRAS Study)
Status:
Unknown status
Trial end date:
2016-03-01
Target enrollment:
Participant gender:
Summary
Renal atherosclerotic stenosis (RAS) is a prevalent cause of secondary hypertension (HT).
Since there are still uncertainties as to whether and in what patients revascularization by
means of percutaneous renal angioplasty (PTRAS) should be pursued, we designed a study
exploiting an optimized patient selection strategy and using hard experimental endpoints to
unravel these uncertainties.
Primary objective: to determine if revascularization by means of PTRAS is superior or
equivalent to optimal medical treatment for preserving glomerular filtration rate in the
ischemic kidney as assessed by 99mTcDTPA sequential renal scintiscan.
Secondary objectives: to determine if the two treatments are equivalent in lowering blood
pressure (BP), preserving overall renal function and regressing damage in the target organs
of hypertension.
Design: prospective multicenter randomized, unblinded two-arm study.
Eligible patients will have clinical and/or radiological evidence of unilateral or bilateral
RAS, defined by stenosis of the proximal portion of the renal artery and its main
bifurcations at angioCT. Duplex scan will exclude nephroangiosclerosis as the latter could
bias the assessment of the outcome of revascularization.
Inclusion criteria. RAS affecting the main renal artery or its major branches at angio-CT
either > 70% or, if < 70 with post-stenotic dilatation.
Renal function will be assessed with 99mTc-DTPA renal scintigraphy.
Sample size (30 patients per arm) was calculated to have a 90% power to detect a difference
in means of GFR in the vascularized (or control untreated kidney) of 7.5 ml/min.
Arms
1. Revascularization: digital scan angiography and PTA with stenting of the renal artery at
the ostium or at truncular level, plus optimal medical therapy.
2. Medical therapy: the drug regimen that had been optimized during the run-in period.
Experimental endpoints:
The absolute value of GFR assessed by 99TcDTPA in the ischemic kidney will be used as
quantitative variable and compared between groups at each time point. A categorical
definition of kidney loss, defined as a GFR in the ischemic kidney of < 5 ml/min, will be
also used and the rate of achievement of such endpoint will be compared.
Duration: 5 years.