AUTHOR=Vinciguerra Mattia , Romiti Silvia , Wretschko Eleonora , D'Abramo Mizar , Rose David , Miraldi Fabio , Greco Ernesto 

TITLE=Mitral Plasticity: The Way to Prevent the Burden of Ischemic Mitral Regurgitation?

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 8 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2021.794574

DOI=10.3389/fcvm.2021.794574

ISSN=2297-055X

ABSTRACT=The ischemic impairment of the left ventricular contractility, followed by an adverse remodeling leading to the displacement of the papillary muscles, increased tethering forces and loss of valve competence has been the long-term accepted definition of the ischemic mitral regurgitation. 
Over the years, different approaches of management have attempted to address valve regurgitation, nevertheless failing to achieve satisfactory outcomes. 
Recent studies have observed some structural and molecular changes of the mitral valve, challenging the concept of a bystander passive to the subvalvular involvement. Indeed, the solely mechanical stretch of the papillary muscles, as in dilated left ventricle due to aortic valve regurgitation, is not enough in causing relevant mitral valve regurgitation. This setting triggers a series of structural changes called ‘‘mitral plasticity’’, leaflets increase in their size among others, ensuring an adequate systolic area closure.  
In contrast, the ischemic injury not only triggers the mechanical stretch on the subvalvular apparatus, but is also a powerful promotor of profibrotic processes, with an upregulation of the TGF-β signaling pathway, leading to a mitral valve with exuberant leaflet thickness and impaired mobility.
In this article we revise the concept of ischemic mitral regurgitation, particularly focusing on the new evidence that support dynamic changes in the mitral valve apparatus apparatus, discussing the consequent clinical insights of ‘‘mitral plasticity’’ and the potential therapeutic implications.