title: Resistance to antihypertensive medication as predictor of renal artery stenosis: comparison of two drug regimens.
abstract: BACKGROUND
  Renal artery stenosis is among the most common curable causes of hypertension. The definitive diagnosis is made by renal angiography, an invasive and costly procedure. The prevalence of renal artery stenosis is less than 1% in non-selected hypertensive patients but is higher when hypertension is resistant to drugs.
  
  
  OBJECTIVE
  To study the usefulness of standardised two-drug regimens for identifying drug-resistant hypertension as a predictor of renal artery stenosis.
  
  
  METHODS
  Prospective cohort study carried out in 26 hospitals in The Netherlands.
  
  
  METHODS
  Patients had been referred for analysis of possible secondary hypertension or because hypertension was difficult to treat. Patients < or =40 years of age were assigned to either amlodipine 10 mg or enalapril 20 mg, and patients >40 years to either amlodipine 10 mg combined with atenolol 50 mg or to enalapril 20 mg combined with hydrochlorothiazide 25 mg. Renal angiography was performed: (1) if hypertension was drug-resistant, ie if diastolic pressure remained > or =95 mm Hg at three visits 1-3 weeks apart or an extra drug was required, and/or (2) if serum creatinine rose by > or =20 micromol/L (> or =0.23 mg/dL) during ACE inhibitor treatment.
  
  
  RESULTS
  Of the 1106 patients with complete follow-up, 1022 had been assigned to either the amlodipine- or enalapril-based regimens, 772 by randomisation. Drug-resistant hypertension, as defined above, was identified in 41% of the patients, and 20% of these had renal artery stenosis. Renal function impairment was observed in 8% of the patients on ACE inhibitor, and this was associated with a 46% prevalence of renal artery stenosis. In the randomised patients, the prevalence of renal artery stenosis did not differ between the amlodipine- and enalapril-based regimens.
  
  
  CONCLUSIONS
  In the diagnostic work-up for renovascular hypertension the use of standardised medication regimens of maximally two drugs, to identify patients with drug-resistant hypertension, is a rational first step to increase the a priori chance of renal artery stenosis. Amlodipine- or enalapril-based regimens are equally effective for this purpose.
authors.affiliation: Department of Internal Medicine, University Hospital Rotterdam, The Netherlands. b.v.jaarsveld@utr.dianet.nl
authors.forename: B C
authors.initials: BC
authors.lastname: van Jaarsveld
authors.forename: P
authors.initials: P
authors.lastname: Krijnen
authors.forename: F H
authors.initials: FH
authors.lastname: Derkx
authors.forename: J
authors.initials: J
authors.lastname: Deinum
authors.forename: A J
authors.initials: AJ
authors.lastname: Woittiez
authors.forename: C T
authors.initials: CT
authors.lastname: Postma
authors.forename: M A
authors.initials: MA
authors.lastname: Schalekamp
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017311:Amlodipine / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001262:Atenolol / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D015331:Cohort Studies; D004351:Drug Resistance; D004359:Drug Therapy, Combination; D004656:Enalapril / Q000627:therapeutic use; D005260:Female; D006801:Humans; D006852:Hydrochlorothiazide / Q000627:therapeutic use; D006977:Hypertension, Renal / Q000188:drug therapy* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011859:Radiography; D012077:Renal Artery / Q000000981:diagnostic imaging; D012078:Renal Artery Obstruction / Q000150:complications* / Q000000981:diagnostic imaging*
chemical_list: D000959:Antihypertensive Agents; D006852:Hydrochlorothiazide; D017311:Amlodipine; D001262:Atenolol; D004656:Enalapril