title: Selection of patients for renal artery repair using captopril testing.
abstract: BACKGROUND
  Prediction of improvement following surgical or radiologic intervention in patients thought to have renovascular hypertension (RVH) is often unreliable. Use of the angiotensin-converting enzyme inhibitor captopril in conjunction with measurement of peripheral renin levels or radioisotope renograms is thought to detect patients with functionally significant renal artery stenosis. However, it is unclear whether these tests can identify patients whose hypertension will significantly improve after renal artery repair.
  
  
  METHODS
  The records of 52 consecutive hypertensive patients undergoing captopril studies followed by renal artery repair were reviewed. All patients had either renal artery stenosis > 75% or renal artery occlusion. Preprocedure evaluation included a captopril challenge test (measurement of peripheral renin levels after captopril ingestion) (n = 12) or a captopril renogram (determination of renal blood flow and glomerular filtration rate before and after captopril administration) (n = 40). Either renal artery bypass/nephrectomy (n = 41) or balloon angioplasty (n = 11) was done in all patients (18 bilateral/34 unilateral). No periprocedural deaths occurred. All surgically placed bypass grafts were shown to be patent by contrast or carbon dioxide arteriography before hospital discharge.
  
  
  RESULTS
  Preprocedure captopril tests were positive (suggestive of RVH) in 39 patients (75%) and negative in 13 (25%). All patients with positive captopril tests had improvement in their RVH after intervention (17 cured, 22 improved) while 8 of 13 patients with negative captopril tests had no improvement in blood pressure control. Four of five false-negative tests were associated with a unilateral total renal artery occlusion, making detection of a postcaptopril effect impossible. If these 4 patients are excluded from analysis, preprocedure captopril testing was 98% accurate in predicting postprocedure outcome.
  
  
  CONCLUSIONS
  Preprocedure captopril testing permits extremely accurate selection of patients with renal artery stenosis who will benefit from renal artery repair.
authors.affiliation: Department of Surgery, University of Florida College of Medicine, Gainesville 32610-0286, USA.
authors.forename: T R
authors.initials: TR
authors.lastname: Harward
authors.forename: B
authors.initials: B
authors.lastname: Poindexter
authors.forename: T S
authors.initials: TS
authors.lastname: Huber
authors.forename: L M
authors.initials: LM
authors.lastname: Carlton
authors.forename: T C
authors.initials: TC
authors.lastname: Flynn
authors.forename: J M
authors.initials: JM
authors.lastname: Seeger
mesh_terms: D000328:Adult; D000368:Aged; D000800:Angioplasty, Balloon; D001157:Arterial Occlusive Diseases / Q000175:diagnosis; D002216:Captopril; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006977:Hypertension, Renal / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy; D018579:Patient Selection; D011866:Radioisotope Renography; D012077:Renal Artery / Q000601:surgery*; D012078:Renal Artery Obstruction / Q000175:diagnosis*; D012083:Renin / Q000097:blood
chemical_list: D002216:Captopril; D012083:Renin