ABSTRACTS PRESENTADOS AL 11th INTERNATIONAL SYMPOSIUM "RADIONUCLIDES IN NEPHRO-UROLOGY", REALIZADO EN MONTEREY, CALIFORNIA, 13-17 MAYO 2001.

 

14. LOSARTAN RADIONUCLIDE RENAL SCINTIGRAPHY (LRS) IN THE DETECTION OF HEMODYNAMICALLY SIGNIFICANT RENAL ARTERY STENOSIS (RAS)

J. Bharathi Dasan, A. Malhotra, A. Maini, S.K. Agarwal, R. Kumar. Deep N Strivastava, GP.Bandopadhyaya.
Dept of Nuclear Medicine. Dept of Nephology. Dept of Radiodiagnosis. All India institute of Medical Sciences. New Delhi. India.

 

Aim: The purpose of this study was to compare the role of Losartan radionuclide renal scintigraphy (LRS) and Captopril renal scintigraphy (CRS), in the detection of hemodynamically significant RAS.

Materials and Methods: A total of 25 patients 17 males and 8 females, were evaluated for the presence of hemodynamically significant RAS using LRS and CRS. All patients underwent LRS and subsequently CRS. This was followed by a baseline study if either or both of these tests showed abnormal findings. All the 3 studies were performed using Tc99m-DTPA, within a period of 10 days. Intra Arterial Digital Subtraction Angiography (IADSA) was done within 2 weeks of these studies in 19 patients who had high or moderate probability of RAS on clinical grounds as well as on scintigraphy. The remaining six patients with low probability LRS and CRS studies did not undergo IADSA. All studies were evaluated on the basis of the consensus criteria of 1996 for the detection of renovascular hypertension.

Results: Out of the 19 patients, 13 had unilateral (U/L) RAS, 3 had bilateral (B/L) RAS and 3 had bilateral normal renal arteries on IADSA. Of the 13 patients with unilateral RAS, LRS and CRS were concordant in 8 patients (5 had immediate probability and 3 had high probability on both LRS and CRS). Five patients had discordant results (4 patients had high probability LRS and immediate probability on CRS. However 1 patient had false negative LRS but high probability CRS). All the 3 patients with bilateral RAS had discordant results. Two patients with high probability on LRS for bilateral RAS were found to have bilateral significant RAS (>70%) but in both the cases CRS was of intermediate probability for unilateral RAS. The third patient had LRS suggestive of unilateral RAS and CRS suggestive of bilateral RAS, the IADSA revealed > 70% stenosis on one side and 40% stenosis on other side. All patients with discordant results (5 U/L) and 3 B/L) had small kidneys. In all these patients LRS showed high probability while CRS was of immediate probability except on one. All 3 patients with bilateral normal renal arteries had concordant results (1 was false positive and 2 were true negative with LRS and CRS)

Conclusion: Losartan renal scintigraphy might be a useful noninvasive test for the detection of hemodynamically significant renal artery stenosis in patients with small kidneys and intermediate probability captopril renal scintigraphy.