Severe tricuspid regurgitation with biannular disjunction requiring surgical treatment: A case report

Background Tricuspid annular disjunction (TAD) is an annular disjunction of the right-sided heart. Although TAD is often concomitant with mitral annular disjunction (MAD), it often presents as mitral regurgitation (MR), rather than tricuspid regurgitation (TR). While the clinical significance of MAD has been well-established, there is still little data on TAD. This is a rare case of severe TR due to TAD that appears to be isolated from MAD. Case summary A 63-year-old female complaining of pre-syncope and dyspnoea on exertion was referred to our department. Initial transthoracic echocardiography showed MR and TR due to tricuspid valve prolapse (TVP). On transoesophageal echocardiography, the TVP consisted of an excessively redundant anterior leaflet, where the annular disjunction and severe regurgitation were formed. She recently underwent mitral and tricuspid valve plasties for symptomatic primary severe TR. Discussion This case report emphasizes the clinical significance of TAD as a potential cause of severe TR, even without significant MR. Tricuspid annular disjunction progresses more gradually compared with MAD. This case suggests that remodelling of the right atrium, particularly in chronic atrial fibrillation, may contribute to the development of TR. Despite diagnostic challenges due to the flexible and dynamic nature of the tricuspid annulus, this is the first report of TAD-induced severe TR necessitating surgical intervention. Accurately diagnosing TAD remains challenging with current imaging modalities, emphasizing the need for improved diagnostic tools to optimize treatment strategies.