Reverse remodeling of mitral leaflets after medical treatment in recent-onset dilated cardiomyopathy.

Background: The growth of mitral leaflets (MLs) adaptive to left ventricluar (LV) remodeling has been observed. However, the elasticity of MLs upon mechanical stimuli would be supposed if it shrinks with LV reverse remodeling (LVRR).

Material and methods: Patients with idiopathic recent-onset dilated cardiomyopathy (RODCM) (n = 82) and 50 matched normal controls (NC) were prospectively enrolled. Echocardiography was performed at baseline and 6 months of follow-up for the anterior and posterior mitral leaflet (AML and PML) length, mitral annular dimension (MAD), and tenting height (TH). LVRR was measured as a ≥ 15% reduction in LV end-diastolic volume (LVEDV).

Results: After 6 months, LVRR was achieved in 69.5% of patients. The AML (28 ± 3 vs. 26 ± 3 mm, p = 0.004) and PML (19 ± 4 vs. 17 ± 3 mm, p < 0.001) decreased in length, as well as the MAD (31 ± 5 vs. 28 ± 5 mm, p = 0.001) and TH (10 ± 3 vs. 8 ± 2 mm, p < 0.001). Compared with the NC group, the AML and PML of the RODCM group were 16.7% and 35.7% longer at baseline and remained 8.3% and 21.2% longer at follow-up, respectively. The change in AML or PML correlated moderately with that in LVEDV (r = 0.487, p < 0.001; r = 0.516, p < 0.001, respectively). The AML and PML length decreased in the LVRR (+) subgroup (AML, 28 ± 3 vs. 26 ± 3 mm, p = 0.001; PML, 20 ± 4 vs. 16 ± 3 mm, p < 0.001), but remained the same in the LVRR (-) subgroup (27 ± 4 vs. 28 ± 4 mm, p = 0.318; 17 ± 3 vs. 17 ± 3 mm, p = 0.790).

Conclusions: Enlarged MLs could reverse accompanied by LV reverse remodeling. This study provided the other facet of ML plasticity adaptive to mechanical stretching.