AUTHOR=Vinciguerra Mattia , Sitges Marta , Luis Pomar Jose , Romiti Silvia , Domenech-Ximenos Blanca , D'Abramo Mizar , Wretschko Eleonora , Miraldi Fabio , Greco Ernesto 

TITLE=Functional Tricuspid Regurgitation: Behind the Scenes of a Long-Time Neglected Disease

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.836441

DOI=10.3389/fcvm.2022.836441

ISSN=2297-055X

ABSTRACT=Severe tricuspid valve regurgitation has been for a long time a neglected valve disease, which has only recently attracted increasing interest due to the notable negative impact on the prognosis of patients with cardiovascular disease. 
It is estimated that around 90% of tricuspid regurgitation is diagnosed as ‘‘functional’’ and mostly secondary to a primary left-sided heart disease, and therefore has been usually interpreted as a benign condition that did not require a surgical management. 
Nevertheless, the persistence of severe tricuspid regurgitation after left-sided surgical correction of a valve disease, particularly mitral valve surgery, has been associated to adverse outcomes, worsening of the quality of life and a mortality rate significant increase. Similar results have been found when the impact of isolated severe tricuspid regurgitation has been studied. 
Current knowledge is shifting the ‘‘functional’’ categorization towards a more complex and detailed pathophysiological classification, identifying various phenotypes with completely different etiology, natural history and, potentially, an invasive management. 
The aim of our review is to offer a comprehensive guide for clinicians and surgeons with a systematic description of ‘‘functional’’ tricuspid regurgitation subtypes, an analysis centered on the effectiveness of existing surgical techniques and a focus on the emergent percutaneous procedures. This latter may be an attractive alternative to a standard surgical approach in patients with high-operative risk or isolated tricuspid regurgitation.