DETERMINANTS OF FUNCTIONAL TRICUSPID REGURGITATION IN INCOMPLETE TRICUSPID-VALVE CLOSURE - DOPPLER COLOR-FLOW STUDY OF 109 PATIENTS

Objectives. The aim of this study was to investigate the association between the pattern of incomplete tricuspid valve closure and the presence of tricuspid regurgitation and to identify factors that determine the severity of regurgitation associated with this pattern. Background. The incomplete tricuspid valve closure pattern (defined as apical displacement of the leaflets) has been described by two dimensional echocardiography. However, whether this pattern is universally associated with tricuspid regurgitation and the determinants of severity of regurgitation in its presence have not been studied by Doppler color flow mapping. Methods. We identified 109 consecutive patients (mean age 62 +/- 17 years) with incomplete tricuspid valve closure who were studied by Doppler color flow mapping. We measured the linear apical displacement of the coaptation point from the tricuspid annulus and the area of displacement between the leaflets and annulus. Right atrial, ventricular and annular dimensions were measured and compared with those in a group of normal subjects. Results. Tricuspid regurgitation was present in all patients with the incomplete closure pattern; it was mild in 14%, moderate in 19% and severe in 67%. Apical displacement was significantly greater (p < 0.02) in those with severe regurgitation than in those with mild regurgitation or in normal subjects. Tricuspid annulus dilation was the only independent predictor of severity of regurgitation. The right ventricle was not significantly dilated in 32% of patients, and right ventricular systolic pressure was not correlated with the severity of regurgitation and was < 30 mm Hg in 11% of patients. Conclusions. Tricuspid regurgitation was associated with incomplete tricuspid valve closure in all patients studied and was moderate to severe in 86%. Impaired coaptation is best reflected by the displacement area between the leaflets and the annulus. High pulmonary pressure and significant right ventricular dilation are not prerequisites for functional tricuspid regurgitation. Annular dilation is the most consistent and important determinant of this lesion.