Doppler ultrasonography in posttransplant renal artery stenosis: A reliable tool for assessing effectiveness of revascularization?

Background. Renal artery stenosis is usually treated by angioplasty and stenting, but the effectiveness of graft perfusion is difficult to establish on clinical grounds. Methods. We compared changes in Doppler ultrasound parameters such as resistive index and peak systolic velocity with concomitant changes in renal vascular resistances, renal blood velocity, and wall shear stress measured before and 1 month after percutaneous transluminal angioplasty and stenting in 12 renal transplant patients with renal artery stenosis. Results. After revascularization, peak systolic velocity and resistive index normalized in all patients. Changes in peak systolic velocity (-72%; P<0.001 vs. basal) were positively correlated (P<0.0001; r=0.87) with those in renal blood velocity (-88%; P<0.01 vs. basal) And with those.(P<0.0005; r=0.80) in wall shear stress (-97%; P<0.005). Changes in resistive index (+21%; P<0.005) were negatively correlated (P=0.009; r=0.51) with those in renal vascular resistances (-40%; P<0.01). Changes in Doppler parameters (resistive index and peak systolic velocity) reflected those in renal vascular resistances and renal blood velocity with 100% sensitivity and specificity. Conclusions. Doppler ultrasound is a reliable, non-invasive, and easily available tool for identifying subjects who may benefit from kidney graft revascularization and to assess the effectiveness of the procedure.