Morphological Assessment of the Tricuspid Apparatus and Grading Regurgitation Severity in Patients With Functional Tricuspid Regurgitation: Thinking Outside the Box.

Current guidelines recommend transthoracic echocardiography to assess patients with functional tricuspid regurgitation (FTR) because it provides information regarding the presence of structural abnormalities of the tricuspid valve (TV), allows measurement of tricuspid annulus diameter, and evaluates severity of FTR by integrating data obtained from 2D and Doppler echocardiography. Critical components of the noninvasive evaluation include information regarding TV anatomy, tricuspid regurgitation severity, right ventricular size and systolic function, and associated findings such as estimated pulmonary artery pressure. However, most of the parameters included in the current recommendations to assess FTR are derived from the experience and knowledge developed about the mitral valve and have been transferred from the left to the right side of the heart without accounting for differences in anatomy of the tricuspid and mitral apparatus or for differences in hemodynamic environment in which the TV operates compared to its left counterpart.