Changes in renal blood flow reserve after angioplasty of renal artery stenosis in hypertensive patients

Abstract

Intra-arterial Doppler is a recent technique which allows assessment of distal vascular disease using measurements of intrarenal blood flow velocities. The purpose of this study was to evaluate intrarenal hemodynamics and renal blood flow reserve before and after percutaneous transluminal angioplasty (PTA) in hypertensive patients with unilateral atherosclerotic renal artery stenosis using intra-arterial Doppler. Intra-arterial Doppler was performed during arteriography in 19 hypertensive patients (12 men; mean age, 64 +/- 8 years) in "normal" and in "stenotic" kidneys at baseline, on isosorbide dinitrate, and after selective intra-renal papaverine injection, before, and after PTA. Doppler parameters analyzed were average peak velocity, maximum peak velocity, end diastolic velocity, and renal blood flow (RBF). Changes in Doppler parameters after papaverine injection were also analyzed. The major results were (1) the significant reduction in RBF distal to the stenosis, (2) the lack of arteriolar reactivity in response to papaverine distal to the stenosis, (3) the immediate recovery of arteriolar reactivity after PTA, associated with restoration of RBF in the revascularized kidneys, and (4) no change in arteriolar reactivity in response to papaverine in the "normal" kidneys following PTA. Ours results highlighted the benefit of endovascular Doppler to evaluate (1) RBF reserve, and (2) the repercussion of the stenosis on the distal vascularization.