title: Plasma levels of brain natriuretic peptide in various forms of obstruction to the left ventricular outflow tract.
abstract: OBJECTIVE
  The study aim was to evaluate the relationship between plasma concentrations of brain natriuretic peptide (BNP) and the type or degree of stenosis in the left ventricular outflow tract (LVOT).
  
  
  METHODS
  The relationship between BNP plasma level and pressure gradient (PG) in the LVOT and LV wall thickness (LVWth) was analyzed in 25 patients with a PG > or = 30 mmHg in the LVOT from the mid-left ventricle to the aortic valve. Among patients, 14 had aortic valve stenosis (AS), five had subaortic type hypertrophic obstructive cardiomyopathy (HOCM), three had mid-ventricular type HOCM, and three had angled ventricular septum. Three patients with AS showed LV systolic dysfunction (ejection fraction (EF) < 50%). All patients were in sinus rhythm. LV peak-systolic pressure (LVPSP) was derived by adding maximum PG to cuff systolic arterial pressure.
  
  
  RESULTS
  In AS patients without LV systolic dysfunction and HOCM patients, there was a significant positive correlation between BNP and LVPSP (r = 0.78, p = 0.001; r = 0.76, p = 0.007, respectively). In AS patients without LV systolic dysfunction, BNP was positively correlated with LVWth (r = 0.79, p = 0.001), but no correlation was found between BNP and LVWth in patients with HOCM. In AS patients including systolic LV dysfunction, BNP was negatively correlated with LVEF (r = -0.87, p < 0.0001), but no correlation was found between BNP and LVEF in patients with HOCM.
  
  
  CONCLUSIONS
  These results suggest that BNP level is closely associated with severity of stenosis in patients with HOCM, but mainly with severity of stenosis and also degree of LV systolic dysfunction in patients with AS. The BNP-LVWth relationship appeared to differ between AS (a fixed stenosis with uniform myocardial hypertrophy) and HOCM (a dynamic stenosis with uneven myocardial hypertrophy).
authors.affiliation: Department of Cardiology and Clinical Research, National Zentsuji Hospital, Zentsuji City, Kagawa, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Fukuda
authors.forename: Hisanori
authors.initials: H
authors.lastname: Shinohara
authors.forename: Koichi
authors.initials: K
authors.lastname: Sakabe
authors.forename: Teru
authors.initials: T
authors.lastname: Nada
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Tamura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D015150:Echocardiography, Doppler; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D011336:Probability; D011379:Prognosis; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013318:Stroke Volume; D016277:Ventricular Function, Left / Q000502:physiology; D014694:Ventricular Outflow Obstruction / Q000175:diagnosis*; D017725:Ventricular Pressure / Q000502:physiology*
chemical_list: D015415:Biomarkers; D020097:Natriuretic Peptide, Brain