ASSESSMENT OF RENAL ARTERY STENOSIS USING FRACTIONAL FLOW RESERVE - CORRELATION WITH ANGIOGRAPHY AND ULTRASONOGRAPHY: PP.30.197

Abstract

Objective: The aim of the study was to investigate fractional flow reserve and translesional pressure gradient in moderate to high grade renal artery stenosis (RAS) with respect to angiographic measurements and Doppler-ultrasonography. Design and Method: 43 hypertensive patients (22F, 21 M, mean age 58.5 years) with at least moderate (more than 50%) RAS were investigated. Using the pressure wire, translesional systolic pressure gradient (TSPG), resting Pd/Pa ratio (the ratio of mean distal to lesion and mean proximal pressures) and hyperemic renal fractional flow reserve (rFFR) - after administration of 30 mg intrarenal papaverine- were evaluated. Quantitative angiographic analysis of stenosis severity was performed including minimal lumen diameter (MLD) and percent diameter stenosis (DS) assessment. Renal:aortic ratio (RAR) and resistive index were obtained in Doppler-duplex ultrasonography. The predictive value of different variables was calculated using Receiver-operating characteristics (ROC) curves. Results: Mean Pd/Pa ratio was 0.85+/−0.12 and decreased to 0.79+/−0.13 after papaverine administration. Both Pd/Pa ratio and rFFR strongly correlated with MLD (r = 0.56, p < 0.001 and r = 0.63, p < 0.001) and DS (r = −0.52, p < 0.01 and r = −0.57,p < 0.001). Patients with Pd/Pa ratio < 0.9 had non-significantly increased RAR (3.43 vs 3.03,p = 0,11) as compared to those with normal Pd/Pa ratio. Patients with rFFR<0.8 had non-significantly increased RAR (3.44 vs 3.02,p = 0.09) in comparison to patients with normal rFFR. In assessment of more than 50% RAS (in QCA) the areas under the curves for Pd/Pa and rFFR were 0.913 and 0.920 respectively (p < 0.001 and p <0.001). The sensitivity and specifity for Pd/Pa ratio<0.9 were 100% and 62,5% and for rFFR<0.8 100% and 59,4% respectively. The most predictive cut-off values for RAS were: <0.92 for Pd/Pa ratio (100% specificity and 75% sensitivity) and <0.83 for rFFR (100% specificity and 75% sensitivity). Conclusions: Mean Pd/Pa ratio and renal fractional flow reserve correlated strongly with angiographic data and in a less pronounced manner with parameters reflecting intrarenal blood flow. The best accuracy cut-off points for renal artery stenosis predicting were <0.92 and <0.83 respectively.