title: N-terminal pro-brain natriuretic peptide as a biomarker for a significant renal artery stenosis in medically refractory hypertensive patients.
abstract: BACKGROUND
  Although RAS is a relatively uncommon cause of hypertension, it is the most common form of correctable hypertension. There are clinical clues to be gained in identifying the small subset of individuals in whom directed evaluation for RAS may be useful. But its diagnostic accuracy is still poor.
  
  
  OBJECTIVE
  The aim of the present study is to determine the usefulness of N-terminal pro-brain natriuretic peptide (NT-pro BNP) levels in helping improved diagnostic accuracy of a significant renal artery stenosis (RAS) in medically refractory hypertensive patients.
  
  
  METHODS
  The present study included 40 patients with medical refractory hypertension in whom RAS was suspected and who were undergoing magnetic resonance angiogram (MRA) of renal artery and/or renal angiogram. Twenty consecutive patients with a significant RAS by MRA or renal angiogram (RAS group) compared with 20 consecutive patients in whom RAS was suspected but whose MRA/renal angiogram was normal or non-significant (normal group). Baseline clinical characteristics, number of antihypertensive medications before the procedure and NT-pro BNP were obtained from both groups.
  
  
  RESULTS
  Age, gender glomerular filtration rate (GFR) and LV function did not differ significantly between the two groups. NT-pro BNP level was significantly higher in RAS group (1,243 ng/ml, range 156-10,628 ng/ml) compared to normal group (129 ng/ml, range 61-3,457 ng/ml), p = 0.009. NT-proBNP level > or = 600 ng/ml has sensitivity and specificity of 80% and 95%, respectively, in diagnosis of significantRAS.
  
  
  CONCLUSIONS
  In medical refractory hypertensive patients, NT-pro BNP level increased in patients with significant RAS and was an aid in separating a significant RAS from non-significant/normal renal artery.
authors.affiliation: Division of Cardiology, Department of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand. Wongpraparut@yahoo.com
authors.forename: Nattawut
authors.initials: N
authors.lastname: Wongpraparut
authors.forename: Komoltri
authors.initials: K
authors.lastname: Chulaluk
authors.forename: Srisakul
authors.initials: S
authors.lastname: Chirakamjanakorn
authors.forename: Rewat
authors.initials: R
authors.lastname: Phankingthongkum
authors.forename: Sarawut
authors.initials: S
authors.lastname: Limtangturakulm
authors.forename: Rungtiwa
authors.initials: R
authors.lastname: Pongakasira
mesh_terms: D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000150:complications* / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D011446:Prospective Studies; D012078:Renal Artery Obstruction / Q000097:blood* / Q000150:complications*
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain