Changes in mitral annular geometry and dynamics with ß-blockade in patients with degenerative mitral valve disease.
BACKGROUND
remodeling of the mitral annulus contributes to progression of mitral regurgitation (MR). In patients with moderate-to-severe MR, short-term treatment with β-blockers has been shown to increase left ventricular (LV) end-diastolic and end-systolic volume, and this could deleteriously increase mitral valve annular dimensions. The objective of this study was to quantify the effects of a short duration of β-blocker treatment on mitral annular dimensions and dynamics in patients with MR due to primary degenerative valve disease.


RESULTS
twenty-five patients with moderate-to-severe degenerative MR and normal LV systolic function were studied in a double-blind crossover experiment using a β1-selective adrenergic blocker and placebo administered for 14±3 days. Cardiac MRI images were acquired after each treatment period to quantify mitral annular dimensions. At end diastole, there was no change in annular area (1659±331 versus 1632±299 mm(2); P<0.19), annular perimeter (154.3±16.4 versus 152±13.9 mm; P<0.13), septal-lateral (SL) dimension (38.0±5 versus 39.0±4.5 mm; P<0.15), or annular height (9.8±3.8 versus 9.5±2.5 mm; P<0.53). β-blockade resulted in significant end-diastole decreases in commissure-commissure dimension (48.9±4.6 versus 47.2±4.0 mm; P<0.01) and eccentricity (1.3±0.2 versus 1.2±0.1; P<0.01). At end systole (ES), β-blockade conferred a small, but significant decrease in annular perimeter (161.0±19.3 versus 156.8±16.9 mm; P<0.04) and eccentricity (1.2±0.1 versus 1.1±0.1; P<0.02), and the SL dimension significantly increased (41.5±5.7 versus 43.0±5.3 mm; P<0.03). Commissure-commissure dimension, annular area, and annular height at ES were not significantly different.


CONCLUSIONS
despite significant increases in LV end-diastolic and end-systolic volume, short-term β-blocker treatment of patients with moderate-to-severe MR reduced or preserved all mitral annular dimensions except SL at ES.
Ennis
Daniel B
DB
Department of Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, Calif. 90095, USA. daniel.ennis@gmail.com
Rudd-Barnard
Gabriel R
GR
Li
Bo
B
Fonseca
Carissa G
CG
Young
Alistair A
AA
Cowan
Brett R
BR
Stewart
Ralph A H
RA
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008790:Metoprolol / Q000627:therapeutic use*; D008875:Middle Aged; D008943:Mitral Valve / Q000187:drug effects* / Q000503:physiopathology; D008944:Mitral Valve Insufficiency / Q000188:drug therapy* / Q000503:physiopathology; D012720:Severity of Illness Index; D016277:Ventricular Function, Left / Q000187:drug effects
D000319:Adrenergic beta-Antagonists; D008790:Metoprolol