PROSPECTIVE-STUDY ON CAPTOPRIL RENOGRAPHY IN HYPERTENSIVE PATIENTS

Six hundred and sixty-seven hypertensive patients were analyzed by captopril-enhanced scintigraphy. If time to reach maximal activity (T(max)) was greater-than-or-equal-to 5 min using Tc-99m-diethylenetriaminepentaacetic acid (DTPA) or greater-than-or-equal-to 3 min with I-123-o-iodohippurate (OIH) and Tc-99m-mercaptoacetyltriglycine (MAG3) and washout time greater-than-or-equal-to 15 min, a control study with nifedipine was performed. If the difference between T(max) under captopril and nifedipine premedication was greater-than-or-equal-to 5 min with Tc-99m-DTPA or greater-than-or-equal-to 3 min with I-123-OIH and Tc-99m-MAG3, the renogram was defined highly suggestive of renovascular hypertension. In the evaluation of bilateral abnormalities an additional parameter was considered, i.e. the presence of functional asymmetry of the emuntories susceptible of partial reversal in the control study under nifedipine. Based on these criteria, 58 out of 66 7 (8.7 %) scintigrams were found to be abnormal. Thirty-five of these 58 patients and 32 of the remaining 609 scintigraphically negative cases underwent additional arteriographic examination. A renal vascular stenosis greater-than-or-equal-to 50% was found in 33 out of 35 (94.20/o) patients with positive scintigraphy and in 3 out of 32 patients with negative scintigraphy. By examining results of the 67 patients undergoing arteriography, the sensitivity of captopril-enhanced scintigraphy was estimated to be 91.6 %, with a specificity of 93.5 %, an accuracy of 92.5 %, and predictive values of a positive or negative result of 94.2 and 90.6 %, respectively. By restricting analysis to bilateral stenosis, sensitivity was found to be 76.9%. Postexamination of 16 patients undergoing revascularization by surgery or percutaenous transluminal renal angioplasty reflected the expected results with a substantial shortening in T(max) and T75 in the responsive cases.