DETECTION OF RENAL-ARTERY STENOSIS WITH DOPPLER SONOGRAPHY BEFORE ANDAFTER ADMINISTRATION OF CAPTOPRIL - VALUE OF EARLY SYSTOLIC RISE

OBJECTIVE. The goal of this study was to assess the value of quantitat ive and qualitative analysis of the early systolic rise on Doppler wav eforms obtained before and after administration of captopril in patien ts suspected of having renal artery stenosis. SUBJECTS AND METHODS. Se venty-one hypertensive patients (135 kidneys) were studied with transr enal Doppler sonography. Ninety-six kidneys were studied again after a dministration of captopril. All patients also underwent renal angiogra phy. All Doppler studies were independently reviewed by two observers. Specific criteria for Doppler waveform patterns that were applied in the detection of renal artery stenosis included acceleration, accelera tion time of early systolic rise, differential velocity of systolic ri se, and resistive index. These criteria were then correlated with angi ography, and receiver operating characteristic curves were generated. RESULTS. On the basis of waveform pattern recognition, Doppler sonogra ms obtained before administration of captopril had a sensitivity of 81 % and a specificity of 98% for the detection of renal artery stenosis greater than or equal to 50%, Sensitivity of Doppler sonography obtain ed after administration of captopril was 100%, and specificity was 100 %. For renal artery stenosis greater than or equal to 70%, sensitivity was 94% and specificity was 89% before administration of captopril, T he area under the receiver operating characteristic curve for the acce leration criterion was significantly larger after administration of ca ptopril (p = .009) for the detection of renal artery stenosis greater than or equal to 50%. After captopril administration, an acceleration threshold value of 440 cm/sec(2) for early systolic rise was associate d with a sensitivity of 100% and a specificity of 94% for the detectio n of renal artery stenosis greater than or equal to 50%. CONCLUSION, D oppler sonography of the renal arteries performed before administratio n of captopril appears to be an excellent screening tool in the detect ion of severe stenosis (greater than or equal to 70%). Administration of captopril improves the detection of renal artery stenosis greater t han or equal to 50% with Doppler sonography when observers use both mo rphologic and quantitative criteria.