Discussion
The present study conducted provides new information on the 3D MV geometry focusing on leaflet tethering and its association with 3D VCA, with a large population of MVP patients.
The principal finding of the present study is that, secondary leaflet tethering is a significant mechanism behind severe degenerative mitral regurgitation, resulting an MVPt+ phenotype featuring more advanced morphological and hemodynamical characteristics.
In detail, (1) we corroborated that TVi and PVi, rather than annular dimension, were the major independent determinants of 3D VCA in MVP patients with significant MR (2) we carefully defined a cutoff value to characterize the occurrence of pathological leaflet tethering in MVP patients (MVPt+ group) (3) apart from marked LV and annular enlargement, MVPt+ group presented significantly greater 3D VCA, elevated plasma levels of NT-proBNP and sPAP (4) Occurrence of leaflet tethering is associated with a 3D VCA ≥ 0.55 cm2 in MVP patients and it could be a specific marker for severe MR (Figure 4). Our findings may bring new insights into risk stratification and surgical decision making to MVP patients.