title: The utility of renal venous renin studies in selection of patients with renal artery stenosis for angioplasty: a retrospective study.
abstract: OBJECTIVE
  Recent studies of renal artery stenosis (RAS) failed to demonstrate greater benefit from angioplasty in terms of blood pressure (BP) lowering than medical treatment. Not all RAS are haemodynamically significant and identification of patients likely to benefit from angioplasty remains essential.
  
  
  METHODS
  We examined whether performing renal venous renin studies under stringent conditions might predict BP improvement. Patients with at least 60% RAS who underwent renal venous renin measurements in 2008-2013 were identified. Renal venous renin lateralization ratios (RVRRs) were calculated by dividing venous renin from the stenotic kidney with contralateral levels before and after stimulation with enalaprilat or captopril. Benefit was defined as BP less than 140/90  mmHg without medication, 10% decreased mean BP without increased daily defined doses (DDDs) or decreased DDD without a significant increase of mean BP.
  
  
  RESULTS
  Twenty-eight patients were treated medically and 42 with angioplasty (median age 60.1 years, 41% male, 29% chronic kidney disease, 50% resistant hypertension). At 11.4 ± 3.3 months, 69% of patients treated with angioplasty had BP benefit compared with 25% with medical treatment (P < 0.001). Logistic regression identified resistant hypertension [odds ratio (OR) 0.18, 95% confidence interval (95% CI) 0.04-0.82, P = 0.03] and baseline DDD (OR 0.69, 95% CI 0.48-0.98, P = 0.04) as being negatively associated, and positive stimulated RVRR (OR 21.6, 95% CI 3.50-133.3, P = 0.001) positively associated with benefit from angioplasty. On multivariate logistic regression, only stimulated RVRR positivity predicted BP benefit (OR 20.5, 95% CI 2.9-145.0, P = 0.003).
  
  
  CONCLUSIONS
  These findings suggest that a positive stimulated RVRR measured under optimal conditions may help to identify patients with RAS likely to improve from angioplasty.
authors.affiliation: aEndocrine Hypertension Research Centre, University of Queensland School of Medicine, Greenslopes and Princess Alexandra Hospitals, Brisbane, Queensland, Australia bHôpital du Sacré-Coeur de Montréal, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Rémi
authors.initials: R
authors.lastname: Goupil
authors.forename: Diane
authors.initials: D
authors.lastname: Cowley
authors.forename: Martin
authors.initials: M
authors.lastname: Wolley
authors.forename: Ashraf H
authors.initials: AH
authors.lastname: Ahmed
authors.forename: Richard D
authors.initials: RD
authors.lastname: Gordon
authors.forename: Michael
authors.initials: M
authors.lastname: Stowasser
mesh_terms: D000368:Aged; D017130:Angioplasty; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D002216:Captopril / Q000627:therapeutic use; D015773:Enalaprilat / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012078:Renal Artery Obstruction / Q000097:blood* / Q000188:drug therapy / Q000503:physiopathology / Q000601:surgery; D012083:Renin / Q000097:blood*; D012189:Retrospective Studies
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D002216:Captopril; D012083:Renin; D015773:Enalaprilat