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- Title
Prediction of Therapy Outcome in Patients with Unilateral Renal Artery Stenosis: A Prospective Study.
- Authors
Voiculescu, A.; Schmitz, M.; Plum, J.; Vupora, S.; Jung, G.; Mödder, U.; Pfeiffer, T.; Sandmann, W.; Grabensee, B.
- Abstract
Objective: The predictive value of the resistance index (RI) measured with colour coded Doppler-sonography (CDS) in patients with renal artery stenosis (RAS) was to be studied before and after ACE-inhibitor (ACE-I) application. Additionally, plasma-renin-activity (PRA), measured in differential renal vein samples, was to be evaluated as possible predictor for improvement of hypertension (HT) after removal of RAS. Methods: Patients with angiographic RAS of >70% diameter reduction were to be studied prospectively. ACE-I had to be withheld at least 14 days before examination. Measurements of blood pressure (24-h-ABDM) as well as RI's (before and 30 minutes after 1.25mg Enalapril i.v) were performed before and 3-6 months after intervention (dilatation or surgery). Further, PRA was measured in differential renal vein samples and the renin ratio (RR) between stenosed and nonstenosed kidney was determined. Improvement of HT was defined by application of a score including 24-h-MAP (mean arterial pressure) and number of antihypertensive drugs (MED) [MAP x (1 + MED/10)]. A decrease in score of >20 was considered as improvement of HT. The value of CDS-parameters as predictors for a failure of improvement of HT after removal of RAS was evaluated with ROC curve analysis. In addition, uni- und multivariate analysis was applied for determination of the predictive value of CDS and hormonal parameters. Results: Between 11/2000 and 2/2004 a total of 50 patients with unilateral RAS were included in the study. With ROC analysis (Fig. 1) we found, that the RI on the stenosis side, before and after ACE-I application, provide a better combination of sensitivities and specificities as compared to the RI's of the contra lateral kidney. A RI > 0.53 in the stenosed kidney after ACE-I predicted a lack of improvement in HT (sensitivity 84%, specificity 83%). A rennin ratio <1:1.5 provided a high sensitivity (100%) for the prediction of therapy failure. In uni- (Fig. 2) und multivariate analysis a RI > 0.53 in the stenosed kidney plus a RR <1:1.5 was the best predictor for a lack of improvement of HT (odds ratio 24, CI 4.5-123). Conclusions: The RI of the kidney behind the stenosis is relevant for the prediction of therapy outcome in patients with unilateral RAS. In our patients the cut-off RI value is 0.53. The additional determination of the renin-ratio adds important information indicating which patient will not have an improvement of HT after removal of stenosis. The additional application of ACE-I during CDS does not significantly improve the predictive value of the RI.
- Subjects
DOPPLER ultrasonography; RENAL artery; STENOSIS; RENIN; BLOOD plasma
- Publication
Kidney & Blood Pressure Research, 2004, Vol 27, Issue 5/6, p298
- ISSN
1420-4096
- Publication type
Article