Three-Dimensional Geometry Values and Clinical Determinants for the Annulus of the Tricuspid Valve in a Japanese Population.

The tricuspid annulus (TA) is the primary target of tricuspid valve (TV) surgery for tricuspid regurgitation (TR). However, the reference values for TA geometry in the Japanese population is currently unavailable. We aimed to elucidate the geometric reference values of the TA in Japanese individuals using 3-dimensional (3D) echocardiography.We conducted a prospective study using transthoracic 3D echocardiography on 142 healthy Japanese subjects aged between 20 and 79 years. The tricuspid geometric parameters in the late-diastole and the mid-systole were analyzed using custom 3D software (Realview™).After excluding 46 subjects with poor images, data from 96 subjects (67.6%) were analyzed. TA area and circumference showed strong correlations with body surface area (BSA) (P < 0.001 for all), while some of these parameters exhibited weak correlations with age. Gender differences in TV geometry were assessed across 3 age groups: 20-39 years (42 subjects), 40-59 years (28 subjects), and 60-79 years (26 subjects). In the youngest subjects (20-39 years), males had a significantly larger TA area and smaller anterior-posterior and medial-lateral diameters (P < 0.001 for all), even after adjusting for BSA, indicating gender differences of TA geometry. These differences diminished with age.We present reference values for TA geometry by age and gender in a Japanese cohort. BSA may be a suitable metric for indexing the TA parameters. While age-related changes in TA parameters may not be significant, gender differences, particularly in younger individuals, persist even after adjusting for BSA.