N-terminal Pro-Brain Natriuretic Peptide as a Biomarker for a Significant Renal Artery Stenosis in Medically Refractory Hypertensive Patients
Nattawut Wongpraparut MD, FACP, FACC *, Chulaluk Komoltri DrPH **, Srisakul Chirakarnjanakorn MD*, Rewat Phankingthongkum MD*, Sarawut Limtangturakulm MD*, Rungtiwa Pongakasira BSc***
Affiliation : The study was presented as a poster presentation at European Society of Cardiology 2010, August 2010, Stockholm, Sweden The study was funding by Chalermprakiat foundation, Faculty of Medicine Siriraj Hospital
* Division of Cardiology, Department of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
** Clinical Epidimiology Unit, Office of Research and Development, Faculty of Medicine,, Siriraj Hospital, Mahidol
University, Bangkok, Thailand
*** Her Majestry’s Cardiac Center, Faculty of Medicine Siriraj Hospital, Mahidol University,
Bangkok, Thailand
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.
Material and Method: 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 > 600 ng/ml has sensitivity and specificity of 80% and 95%,
respectively, in diagnosis of significant RAS.
Conclusion : 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.
Keywords : Resistant hypertension, Renal artery stenosis, NT-proBNP
