Proposal for a Standard Echocardiographic Tricuspid Valve Nomenclature

Objectives: The purpose of this study was to introduce a novel clinically relevant nomenclature system for the TV and determine the relative incidence of each morphological type.

Background: With the rapid development of transcatheter tricuspid valve (TV) repair techniques, there is a growing recognition of the variability in leaflet morphology and a need for a unified nomenclature, which could aid in procedural planning and execution.

Methods: Patients from 4 medical centers (2 in Europe, 2 in the United States) referred for transesophageal echocardiography (TEE) to assess native TV function, were retrospectively analyzed for leaflet morphology with the use of a novel classification scheme. Four morphological types were identified: type I, 3 leaflets; type II, 2 leaflets; type IIIA, 4 leaflets with 2 anterior; type IIIB, 4 leaflets with 2 posterior; type IIIC, 4 leaflets with 2 septal; and type IV, >4 leaflets.

Results: A total of 579 patients were analyzed: mean age 78.1 ± 8.0 years, 50.4% female, 70.9% in atrial fibrillation, and 32.2% with previous left heart surgery or transcatheter intervention. Tricuspid regurgitation was moderate or less in 9.4%, severe in 40.5%, massive in 32.3%, and torrential in 17.7%. The etiology of tricuspid regurgitation was primary in 9.4%, mixed in 10.8%, and secondary in all of the other patients (18.6% atriogenic/isolated). The incidence of type I morphology was 312 of 579 (53.9%), type II was 26 of 579 (4.5%), type IIIA was 15 of 579 (2.6%), type IIIB was 186 of 579 (32.1%), type IIIC was 22 of 579 (3.8%), and type IV was 14 of 579 (2.4%).

Conclusions: A novel TV leaflet nomenclature classification scheme can be used to identify 4 types of TV morphologies with the use of TEE imaging. From this multinational retrospective study, the TV has 3 well defined leaflets in only ∼54% of patients and 4 functional leaflets in ∼39% of patients, with type IIIB (2 posterior leaflets) being the most common of the latter. The utility of this classification scheme deserves further study.