Asymptomatic moderate and severe primary degenerative mitral regurgitation was associated with increased myocardial extracellular volume compared to controls (0.32 vs 0.25, P<0.01).
Cross-Sectional (n=35)
Is asymptomatic chronic primary degenerative mitral regurgitation associated with increased myocardial interstitial fibrosis measured by T1-mapping cardiac MRI compared to controls?
Asymptomatic patients with moderate to severe primary degenerative mitral regurgitation exhibit increased myocardial extracellular volume, indicative of interstitial fibrosis, which correlates with reduced myocardial deformation and exercise capacity.
Absolute Event Rate: 0.32% vs 0.25%
p-value: p=<0.01
BACKGROUND: The optimum timing of surgery in asymptomatic patients with chronic severe primary degenerative mitral regurgitation (MR) remains controversial, and further markers are needed to improve decision-making. There are limited data that wall stress is increased in MR and may result in ventricular fibrosis. We investigated the hypothesis that chronic volume overload in MR is a stimulus for myocardial fibrosis using T1-mapping cardiac MRI. METHODS AND RESULTS: A cross-sectional study of 35 patients (age 60 ± 14 years) with asymptomatic moderate and severe primary degenerative MR (mean effective regurgitant orifice area, 0.45 ± 0.25 cm)(2) with no class I indication for surgery were compared with age and sex controls. Subjects were studied with cardiopulmonary exercise testing, echocardiography, and cardiac MRI. Longitudinal and circumferential myocardial deformation was reduced with MR when left ventricular ejection fraction (67% ± 10%) and N-terminal pro B Natriuretic peptide (126 76-428 ng/L) were within the normal range. Myocardial extracellular volume was increased (0.32 ± 0.07 versus 0.25 ± 0.02, P<0.01) and was associated with increased left ventricular end-systolic volume index (r=0.62, P<0.01), left atrial volume index (r=0.41, P<0.05) but lower left ventricular ejection fraction (r=-0.60, P<0.01), longitudinal function (mitral annular plane systolic excursion, r=-0.46, P<0.01), and peak VO2 max (r=-0.51, P<0.05). In a multivariable regression model, left ventricular end-systolic volume index and left atrial volume index were independent predictors of extracellular volume (r(2)=0.42, P<0.01). CONCLUSIONS: Patients with asymptomatic MR demonstrate a spectrum of myocardial fibrosis associated with reduced myocardial deformation and reduced exercise capacity. Future work is warranted to investigate whether left ventricle fibrosis affects clinical outcomes.
Edwards et al. (Wed,) conducted a cross-sectional in Asymptomatic chronic primary degenerative mitral regurgitation (n=35). Moderate and severe primary degenerative mitral regurgitation vs. Age and sex controls was evaluated on Myocardial extracellular volume (p=<0.01). Asymptomatic moderate and severe primary degenerative mitral regurgitation was associated with increased myocardial extracellular volume compared to controls (0.32 vs 0.25, P<0.01).
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