Characteristics of mitral valve leaflet length in patients with pectus excavatum: A single center cross-sectional study

The mitral valve morphology in patients with pectus excavatum (PE) has not been fully investigated. Thirty-five patients with PE, 46 normal controls, and patients with hypertrophic cardiomyopathy (HCM) who underwent 2 leaflet length measurements of Carpentier classification P2 and A2 using a transthoracic echocardiography were retrospectively investigated. The coaptation lengths and depths, papillary muscle tethering length, and mitral annular diameters were also measured. The P2 and A2 lengths were separately compared between 2 groups: older than 16 years and 16 years or younger. Furthermore, the correlations between actual P2 or A2 lengths and Haller computed tomography index, an index of chest deformity, were investigated in patients with PE exclusively. Among subjects older than 16 years, patients with PE had significantly shorter P2, longer A2, shorter copatation depth, and longer papillary muscle tethering length compared with normal controls. Similarly, patients with PE had significantly shorter P2 and shorter coaptation depth even compared with patients with HCM, while no significant difference was found in A2 length and papillary muscle tethering length. The same tendency was noted between 4 normal controls and 7 age- and sex-matched patients with PE ≤ 16 years old. No significant difference regarding A2/P2 ratio was found between patients with PE older and younger than 16 years. No significant correlation between the Haller computed tomography index and actual mitral leaflet lengths in patients with PE older than 16 years was noted; the same was observed for A2/P2 in all patients with PE. In conclusion, the characteristic features of the shorter posterior mitral leaflet, the longer anterior mitral leaflet, the shorter coaptation depth, and the longer papillary muscle tethering length in patients with PE was demonstrated. This finding might provide a clue regarding the etiology of mitral valve prolapse in PE at its possible earliest form.