Renography: Prediction of Blood Pressure after Dilatation of Renal Artery Stenosis

Abstract

In 60 patients with hypertension and unilateral renal artery stenosis (URAS) radio-hippuran renograms were performed before and 6 weeks after anatomically adequate percutaneous transluminal angioplasty (PTA). Two characteristics of the renographic curves have been analyzed: the difference in time to peak (DTP) between the affected and contralateral kidneys, which would be expected to be positive in blood flow impairment, and the relative hippuran uptake (RHU) in the second minute by the affected kidney as compared with the total uptake by both kidneys: this would be less than 50% in the case of stenosis. Before PTA, both variables were predominantly abnormal. The DTP did not predict the blood pressure response to PTA. The group of patients with a RHU between 25 and 45% comprised all cured patients and predicted a more favorable response of the blood pressure than a RHU of less than 25% and especially more than 45% which group contained 83% patients whose blood pressure failed to respond after PTA. After PTA the DTP did normalize in the majority of patients, but this was not related to the blood pressure response. The RHU increased in patients in whom it had been low initially, but frequently remained low ( < 45%). The increase of the RHU was significantly higher in patients with a favorable blood pressure response. Pretreatment with captopril did intensify the abnormal curves of hippuran and of DTPA renograms in 6 patients with URAS who did respond favorably to PTA. There was no such deterioration in 2 patients whose blood pressure did not change sufficiently after PTA or in 4 patients without renal artery stenosis. In conclusion, renography can to some extent predict the effect of PTA on the blood pressure; possibly captopril pretreatment can improve its predictive ability. Sequential renographies can be used as an indication of improvement of the renal function after PTA.

Nuclear Medicine in Pediatric Nephro-Urology: An Overview

“…Dynamic renal scintigraphy has been utilised in the diagnostic work up of renovascular hypertension (154), especially before and after administration of an angiotensin-converting enzyme (ACE) inhibitor such as captopril (155)(156)(157). Although pre-and post-captopril scintigraphy has been suggested in the investigation of secondary causes of hypertension (158), this technique is weak in bilateral or segmental disease, and its use in the diagnostic algorithm of renovascular hypertension is not routinely advocated (159).…”

Prospective analysis of strategies for diagnosing renovascular hypertension.

“…Geyskes et al 24 report that in 21 patients with renal artery stenosis, postcaptopril renography predicted blood pressure response to surgical correction of the stenosis with sensitivity of 87% but with specificity of only 33%. Data in our 16 patients with renal artery stenosis are similar (sensitivity 91% and specificity 20% for GFR, sensitivity 80% and specificity 20% for ERPF).…”

Renovascular Hypertension

“…There is definitely growing interest in the use of ACEI to enhance the sensitivity of radionuelide studies in the diagnosis of renal artery stenosis (23,52,53,64,82). In normal subjects such agents cause peripheral arterial vasodilatation and lower peripheral resistance (35).…”