COLOR DOPPLER ULTRASOUND IN RENAL-TRANSPLANT ARTERY-STENOSIS - WHICH DOPPLER INDEX

A prospective study comparing colour Doppler ultrasound (US) with the 'gold standard' of intra-arterial digital subtraction angiography in t he evaluation of renal transplant artery stenosis was performed. Both the intrarenal vessels and the transplant renal artery were examined b y Doppler US. Diagnostic arteriography was performed only if, on Doppl er, the peak systolic velocity in the transplant renal artery exceeded 1.5 ms(-1). Of 109 patients, the transplant artery could not be visua lized using colour Doppler US in three, and these were omitted from st atistical analysis. Of the remaining 106 patients, 31 had a peak systo lic velocity greater than 1.5 ms(-1) in the transplant renal artery an d were referred for DSA. Of the multiple renal Doppler indices recorde d, the peak systolic velocity in the transplant artery was the best di scriminating measurement for the detection of renal artery stenosis. A peak systolic velocity of greater than or equal to 2.5 ms(-1) in the transplant renal artery had a sensitivity of 100% and a specificity of 95% for the detection of renal artery stenosis (> 50% diameter reduct ion). Although a significant difference in Pulsatility Index, Resistiv e Index, Acceleration Index and Acceleration Time was recorded from th e intrarenal vessels in the angiographically normal and stenosed group s with Doppler, these measurements were less useful as discriminating diagnostic tests. In conclusion, the peak systolic velocity in the tra nsplant renal artery is the most sensitive Doppler criterion for renal artery stenosis and is sensitive and specific enough to be used as a screening test. The intrarenal acceleration time and index should not be used in isolation.