title: Diagnostic ability of B-type natriuretic peptide and impedance cardiography: testing to identify left ventricular dysfunction in hypertensive patients.
abstract: BACKGROUND
  Patients with hypertension are at high risk for the development of left ventricular dysfunction (LVD). Echocardiography is considered to be the gold standard for diagnosis of LVD; but its cost, complexity, and availability prevents its use for frequent evaluation. Brain natriuretic peptide (BNP) and N-terminal BNP (NT-BNP) can identify heart failure in dyspneic patients. Impedance cardiography (ICG) is a noninvasive method of measuring hemodynamic and electromechanical timing parameters. The objective of this study was to determine the ability of BNP, NT-BNP, and ICG to detect the presence of LVD in patients with hypertension.
  
  
  METHODS
  A convenience sample of subjects undergoing echocardiography who had a history of hypertension or current systolic blood pressure >/=140 mm Hg were enrolled and retrospectively evaluated. Patients with known LVD were excluded. Diagnosis of LVD was determined by the presence of systolic or diastolic dysfunction, valvular or wall motion abnormalities, or left ventricular hypertrophy.
  
  
  RESULTS
  A total of 193 subjects were enrolled: 189 men and four women, age 68.8 +/- 11.7 years. Multivariate regression analysis of history and symptoms, BNP, and ICG parameters identified significant predictor variables for LVD including cardiac index (P = .005), left cardiac work index (P = .008), BNP (P = .017), arrhythmia (P = .023), angina (P = .034), and systemic vascular resistance (P = .048). Receiver operating characteristic (ROC) analysis determined the area under the ROC curve (AUC) of BNP (0.60), NT-BNP (0.67), ICG velocity index (0.66), composite ICG (0.66), ICG combined with BNP (0.70), and ICG combined with NT-BNP (0.73).
  
  
  CONCLUSIONS
  In this high-risk hypertensive population, BNP, NT-BNP, and ICG were useful to identify the presence of LVD. The use of ICG with natriuretic peptide testing may improve the ability to detect LVD.
authors.affiliation: Division of Cardiology and the Department of Medicine, Veterans Affairs Medical Center and University of California, San Diego, San Diego, California 92161, USA.
authors.forename: Vikas
authors.initials: V
authors.lastname: Bhalla
authors.forename: Susan
authors.initials: S
authors.lastname: Isakson
authors.forename: Meenakshi A
authors.initials: MA
authors.lastname: Bhalla
authors.forename: Jeannette P
authors.initials: JP
authors.lastname: Lin
authors.forename: Paul
authors.initials: P
authors.lastname: Clopton
authors.forename: Nancy
authors.initials: N
authors.lastname: Gardetto
authors.forename: Alan S
authors.initials: AS
authors.lastname: Maisel
mesh_terms: D000368:Aged; D019540:Area Under Curve; D002307:Cardiography, Impedance; D004452:Echocardiography; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D009419:Nerve Tissue Proteins / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D012372:ROC Curve; D012189:Retrospective Studies; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology*
chemical_list: D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain