Mechanisms for development of functional tricuspid regurgitation determined by pulsed Doppler and two-dimensional echocardiography.

Mechanisms for the development of functional tricuspid regurgitation (TR) were studied in 41 patients by ultrasound. The severity of TR was classified into 4 grades according to the extent of the regurgitant signal by pulsed Doppler echocardiography (echo). No TR signal was detected in 11 patients; the grade of TR was 1+ in 9 patients, 2+ in 10, 3+ in 8 and 4+ in 9. Using 2-dimensional echo, the tricuspid anular area was estimated from a horizontal and a sagittal diameter of the anulus, and systolic configurations of the tricuspid valve was observed. The tricuspid anular area corrected for body surface area increased with the grade of TR. Anterior displacement of the tips of the tricuspid leaflets was seen in 10 patients with TR of 2+ or greater severity, and its frequency also increased with the grade of TR. Loss of coaptation was seen in 3 patients with 4+ TR and malaligned coaptation was seen in 4 patients with TR of variable degrees. Tricuspid anular dilatation and anterior displacement of the tricuspid leaflet tips causes a separation between the leaflet tips and appears to be the main mechanisms for the development of functional TR. Malaligned coaptation also plays a role in the development of functional TR.