Abstract 856: Renal Tissue Perfusion Increases After Interventional Therapy In Patients With Unilateral Renal Artery Stenosis
Atherosclerotic renal artery stenosis (ARAS) is a frequent finding in patients with atherosclerosis. Revascularization by balloon dilatation and stenting, particularly of unilateral ARAS, remains highly controversial. The role of tissue perfusion is well established in ischemic heart disease, but is not well studied in kidneys. We investigated whether or not ARAS stenting improves renal perfusion. We hypothesized that revascularization of high-grade unilateral ARAS (>50% diameter stenosis obtained by angiography) improves the perfusion of the stenotic and the non-stenotic kidney. We studied 10 patients with unilateral ARAS scheduled for stenting. The cortical perfusion of each kidney was measured quantitatively (“maximal upslope method” as proposed by Vallée et al.) by MRI before, and repetitively after (1–5 days and 3 months), revascularization. We used a turboFLASH (TI 113ms, TE 1.25 ms, TR 3 ms) sequence followed by an intravenous bolus injection of Gd-DTPA (0.04mmol/kg bwt) and obtained dynamic images of the kidneys. The mean renal cortical perfusion (MCRP) of the stenotic kidneys was 2.4±0.65 ml/min/g (mean±SD) before, and 3.14±0.8 ml/min/g (p=0.13) 1–5 days after, stenting. Three months post procedure, the MCRP rose to 4.05±1.7 ml/min/g (p=0.01). Notably, the cortical perfusion of the non-stenotic kidney also improved by 44% percent after stenting, compared to baseline (from 2.91±0.9 to 4.2±1.8; p=0.06). The perfusion difference between stenotic and nonstenotic kidneys was highly significant before stenting (2.4±0.65 ml/min/g vs. 2.91±0.9 ml/min/g; p=0.03). After stenting, perfusion in both kidneys was not different. MCRP of the stenotic kidneys improved directly after intervention. Interestingly cortical perfusion also improves in the non-stenotic kidney, underscoring the pathophysiological importance of activated renin-angiotensin system in ARAS on both kidneys. The improvement of renal perfusion persists at least for 3 months.