title: Duplex ultrasound and renin ratio predict treatment failure after revascularization for renal artery stenosis.
abstract: BACKGROUND
  The aim of this study was to find predictors to identify patients with hypertension who will not improve after removal of renal artery stenosis (RAS).
  
  
  METHODS
  Prospective study of patients with unilateral stenosis (>60% diameter reduction) and hypertension in 24-h measurements despite antihypertensive drugs, who underwent revascularization (surgery/angioplasty). Examinations were performed before treatment and after 3 and 6 months after exclusion of restenosis. Studies included 24-h blood pressure, creatinine clearance, 99Tc MAG3 scintigraphy, and measurements of renal vein plasma renin activity (PRA). Intrarenal resistance indices (RI) were determined with duplex ultrasound before and 30 min after administration of intravenous enalaprilat. Improvement of hypertension was defined by a score consisting of 24-h mean arterial pressure and the number of antihypertensive drugs.
  
  
  RESULTS
  From December 2000 to December 2003, 50 patients completed the study. Improvement of hypertension was observed in 18 patients (36%). Comparison between responders (n = 18) and nonresponders (n = 32) revealed significant differences only for RI and PRA measurements. The largest area under the curve in receiver-operating characteristic (ROC) analysis for prediction of no improvement of hypertension was found for RI (stenosis side), which was nearly identical for measurements before and after administration of angiotensin-converting enzyme (ACE) inhibitor. The highest sensitivities and specificities predicting which patients will not improve were found for RIs > or = 0.55. The highest univariate odds ratio (OR 44, confidence interval [CI] 4.8-404) was found for the parameters of RI > or = 0.55 and a renin ratio of <1:1.5.
  
  
  CONCLUSIONS
  Resistance indices of the poststenotic kidney above 0.55 and a negative renin ratio can predict a poor outcome concerning arterial blood pressure response after restoration of renal blood flow for unilateral renal artery stenosis.
authors.affiliation: Department of Nephrology, Center for Coordination of Clinical Studies, University of Duesseldorf, Duesseldorf, Germany. voicules@uni-duesseldorf.de
authors.forename: Adina
authors.initials: A
authors.lastname: Voiculescu
authors.forename: Michael
authors.initials: M
authors.lastname: Schmitz
authors.forename: Jörg
authors.initials: J
authors.lastname: Plum
authors.forename: Markus
authors.initials: M
authors.lastname: Hollenbeck
authors.forename: Sanya
authors.initials: S
authors.lastname: Vupora
authors.forename: Gregor
authors.initials: G
authors.lastname: Jung
authors.forename: Ulrich
authors.initials: U
authors.lastname: Mödder
authors.forename: Tomas
authors.initials: T
authors.lastname: Pfeiffer
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Sandmann
authors.forename: Reinhard
authors.initials: R
authors.lastname: Willers
authors.forename: Bernd
authors.initials: B
authors.lastname: Grabensee
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D006973:Hypertension / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012078:Renal Artery Obstruction / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery*; D012083:Renin / Q000097:blood*; D017211:Treatment Failure; D018616:Ultrasonography, Doppler, Duplex; D014656:Vascular Surgical Procedures
chemical_list: D012083:Renin