Role of Captopril Renography in the Diagnosis of Renovascular Hypertension B.R. Mittal, MD, DNB, Pradeep Kumar, MD, DNB, Pradeep Arora, MD, DM, Vijay Kher, MD, DM, FAMS, M.K. Singhal, MD, DM, DNB, Atul Maini, MD, and B.K. Das, MD 0 Eighty-six hypertensive patients with clinical suspicion of renovascular hypertension (RVH) were evaluated by captopril renal scintigraphy (CRS) and intra-arterial digital subtraction angiography (IADSA) to determine the usefulness of CRS in the diagnosis of RVH and to predict the outcome of revascularixation procedures. Technetium 99m-diethylenetriaminepentaacetic acid (DTPA) renal scintigraphy was performed on 2 consecutive days before and after captopril administration. Captopril renal scintigraphy was considered positive if there were changes in the time activity curve according to the criteria specified by the American Society of Hypertension working group. Captopril renal scintigraphy data were compared with presence or absence of anatomic renal artery stenosis (RAS). Of 86 hypertensive patients investigated, 45 had RAS. Aortoarteritis was the cause of RAS in 40 (89%) patients. Revascularixation was done in 25 patients, and response to revascularlzation was compared wlth that of captoprll renography. Compared with IADSA, CRS showed a sensitivity of 82.8% and a specificity of g8.2%. Fourteen patients had bilateral RAS on IADSA. In these patients, CRS was suggestive of bilateral disease in seven patients, unilateral in four, and negative in three. Comparison of CRS with the results of revascularixation showed a sensitivity and specificity in detecting curable RAS (RVH) of 95% and loO%, respectively (positive predictive value, 100%; negative predictive value, sS%). In conclusion, we found CRS to be useful in the diagnosis of RVH due to aortoarteritis. 6 1996 by the National Kidney Foundation, Inc. INDEX WORDS: Captopril renography; renovascular hypertension; aortoarteritis; bilateral renal artery stenosis. R ENOVASCULAR hypertension (RVH) is a curable form of high blood pressure. Rec- ognition of this disorder is therefore important. Angiography provides the anatomic diagnosis. However, renal artery stenosis (RAS) on angiog- raphy does not necessarily mean that it is respon- sible for high blood pressure. Earlier procedures for the diagnosis of RVH were invasive.‘** Capto- pril renal scintigraphy (CRS) is a noninvasive examination developed in the last decade to eval- uate the hemodynamic importance of RAS and to diagnose RVH.2-6 In a large group of patients we studied the usefulness of CRS in diagnosing RVH in patients with clinical suspicion of RVH and in predicting the outcome of revasculariza- tion procedures in such patients. PATIENTS AND METHODS Eighty-six hypertensive patients were investigated be- cause of clinical suspicion of RVH. The inclusion criteria were (1) age at onset of hypertension less than 30 or more than 50 years, (2) accelerated or malignant hypertension, (3) presence of constitutional symptoms, claudication, and abdominal bruit, (4) absence of family history of hyperten- sion, (5) blood pressure which had been previously con- trolled that recently became uncontrolled in spite of the addition of other drugs in different combinations, and (6) no clinical evidence of renal parenchymal disease,6 ie, ab- sence of edema, oliguria, and significant proteinuria with or without renal impairment (serum creatinine >1.6 mg/dL was considered renal impairment). Of the 86 patients, 10 had three of the above criteria, 64 had four, and 12 had five. There were 52 males and 34 female patients with a mean age of 24.6 + 9.9 years (age range, 7 to 55 years). In addition to routine and 24-hour urinary and biochemical parameters to rule out other causes of hypertension, all the patients underwent 99”rc-diethylenetriaminepentaacetic acid (DTPA) renal scintigraphy before and after captopril administration followed by intraarterial digital subtraction angiography (IADSA). No patient who had undergone both CRS and IADSA as a part of the diagnostic work-up of hypertension was excluded from the analysis. Of the 45 patients with RAS, 25 underwent various revascularization procedures. Etiology of the RAS was aortoarteritis in 40 (89%); five patients had fibromuscular dysplasia. The diagnosis of aortoarteritis was based on the presence of symptoms and signs of ischemic, inflammatory, large vessel disease as well as classical angio- graphic findings (multifocal area of stenosis, irregularity or aneurysm formation of the aorta or its primary branches or both). Patients with evidence of activity in the form of sys- temic features and increased erythrocyte sedimentation rate received prednisolone 1 mg&$d for 3 months followed by gradual tapering to 0.2 mg/kg/d in another 3 to 6 months. The follow-up period of these patients after revascularization From the Departments of Nuclear Medicine and Nephrol- ogy, Sanjay Gandhi Post Graduate Institute of Medical Sci- ences, Lucknow, India. Received December 14, 1995; accepted in revised form April 16, 1996. Address reprint requests to Vijay Kher, MD, DM, FAMS, Department of Nephrology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, 226014, UP, India. 0 19% by the National Kidney Foundation, Inc. 0272~6386/96/2802-0007$3.00/O American Journal of Kidney Diseases, Vol 28, No 2 (August), 1996: pp 209-213 209