ASSESSMENT OF RENAL RESISTANCE INDEX AFTER CAPTOPRIL TEST BY DOPPLER IN ESSENTIAL AND RENOVASCULAR HYPERTENSION

Ultrasonic duplex scanning has been validated as a noninvasive method to evaluate the kidney arteries and hemodynamic characteristics of ren al blood flow in patients with renal artery stenosis. The purpose of o ur study was to assess the changes in renal vascular impedance in 22 p atients with renovascular hypertension, as compared with 45 essential hypertensives and 15 normotensives, by using the Doppler parameter res istance index (RI) before and after a captopril oral test. After the c aptopril test the Delta RI decreased significantly in the stenotic art ery (P < 0.05). Univariate analysis showed that PRA values after capto pril correlated inversely with the changes of RI only in the stenotic artery (P < 0.05). Thus, our findings suggest that the application of the captopril test to renal echo-Doppler may represent a feasible, non invasive, and inexpensively useful tool in the screening studies aimed at diagnosing renovascular hypertension.