ASPIRIN RENOGRAPHY IN DIAGNOSIS OF UNILATERAL RENOVASCULAR HYPERTENSION

We previously proposed that aspirin can enhance the diagnostic sensiti vity of renography with [I-123] orthoiodohippurate (OIH) in patients w ith suspected unilateral renovascular hypertension (RVH). In this stud y we assessed the sensitivity and specificity of this method. Twenty-f our patients, 14 with unilateral RVH and 10 with essential hypertensio n, were studied. For all patients with RVH, definitive diagnosis was b ased on the results of angiography and the response to renal arterial angioplasty after this study. For ail patients with essential hyperten sion, we confirmed that there was little if any stenosis of the renal artery by digital subtraction angiography or Doppler sonography. Renog raphy with [I-123]OIH or Tc-99m-mercaptoacetyltriglycine (MAG(3)) was done once before and once after the oral administration of aspirin (20 mg/kg). We considered renal blood flow to be decreased if the time to the peak in renography was 5 min or more, and defined the peak times of the kidneys as different if separated by 2 min or more. Unilateral RVH was diagnosed when both criteria were met. Renography before aspir in administration indicated RVH in 7 of the 14 patients with RVH, and renography after aspirin indicated RVH in 13 of the 14 patients. Of th e 10 patients with essential hypertension, renography before and after aspirin administration showed no difference between the kidneys in 8 patients. Thus, aspirin renography increased the sensitivity from 50% to 93%, but did not change the specificity (80%) in the diagnosis of R VH. These results suggest that renography with [I-123]OIH or (TC)-T-99 m-MAG(3) for the diagnosis of unilateral RVH is more sensitive when as pirin is used.