title: Elevated B-type natriuretic peptide despite normal left ventricular function on rest and exercise stress echocardiography in mitral regurgitation.
abstract: OBJECTIVE
  To determine whether elevated B-type natriuretic peptide (BNP) predicts left ventricular (LV) contractile dysfunction on exercise stress echocardiography in patients with severe mitral regurgitation (MR).
  
  
  RESULTS
  Thirty three patients with moderate-to-severe or severe MR, a LV ejection fraction > or =60% and New York Heart Association Class I or II symptoms, and 12 controls underwent resting and exercise stress echocardiography. In 20 MR patients, BNP was within the normal range (mean +/- SD, 7.7 +/- 2.7 pmol/L), and in 13 MR patients, BNP was >12 pmol/L (19.6 +/- 7.6 pmol/L). LV end-systolic volume index after exercise was lower in controls than patients with MR (P < 0.0001), but similar in MR patients with normal and elevated BNP, respectively (controls 8.5 +/- 3.9, MR 20 +/- 7 vs. 20 +/- 9 cm(2)/m(2), P > 0.05). However, pulmonary artery systolic pressure (PAP) after exercise was higher in MR with high BNP (70 +/- 20 vs. 48 +/- 11 mmHg, <0.0001) and controls (38+/-11 mmHg). A two-fold increase in plasma BNP was associated with an average increase in resting PAP of 7.6 (95% CI 2.9, 12.2) mmHg, an increase in post-exercise PAP of 14.4 (95% CI 9.0, 19.9) mmHg and increase in left atrial area index of 2.1 (95% CI 0.5, 3.8) cm(2)/m(2). However, there was no significant association between the plasma level of BNP and any rest or post-exercise measure of LV systolic function (r < 0.25, P > 0.05 for all).
  
  
  CONCLUSIONS
  The plasma level of BNP may be within the normal range in patients with moderate-to-severe or severe MR despite significant increases in LV end-systolic volume. Increase in BNP is associated with pulmonary artery hypertension on exercise and left atrial enlargement even when LV systolic function on exercise stress echocardiography is normal.
authors.affiliation: Department of Cardiology, Middlemore Hospital, Hospital Road, Private Bag 93311, Otahuhu, Auckland, New Zealand. andrewkerr@middlemore.co.nz
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Kerr
authors.forename: O Christopher
authors.initials: OC
authors.lastname: Raffel
authors.forename: Gillian A
authors.initials: GA
authors.lastname: Whalley
authors.forename: Irene
authors.initials: I
authors.lastname: Zeng
authors.forename: Ralph A
authors.initials: RA
authors.lastname: Stewart
mesh_terms: D016022:Case-Control Studies; D025401:Echocardiography, Stress; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000097:blood* / Q000000981:diagnostic imaging; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D011237:Predictive Value of Tests; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000175:diagnosis*; D016277:Ventricular Function, Left / Q000502:physiology
chemical_list: D020097:Natriuretic Peptide, Brain