Background: Whether it is possible to perform morphological evaluation of functional tricuspid regurgitation (FTR) on contrast-enhanced computed tomography (CT) was examined by evaluating the relationships between the parameters measured by contrast-enhanced CT and TR severity on transthoracic echocardiography.
Methods: Fifty patients underwent contrast-enhanced CT. Tricuspid annulus area (TAA), tricuspid annulus circumference (TAC), right ventricular volume (RVV), and the distances between the tips and bases of the papillary muscles were measured on contrast-enhanced CT in diastole and systole. Fifty cases were divided into 34 in the TR ≤ mild group (none TR: 3 cases, trivial TR: 24 cases, mild TR: 7 cases), and 16 in the TR ≥ moderate group (moderate TR: 8 cases, severe TR: 8 cases) using the TR grade measured by transthoracic echocardiography, and then differences between the groups were examined.
Results: Significant differences were found in TAA, TAC, and RVV (p<0.01) and the distances between the tips of the anterior and posterior papillary muscles (p<0.05) in both diastole and systole. Since the septal papillary muscle could not be identified in 18 cases (36.0%), only the distance between the anterior and posterior papillary muscles was measurable in all cases. On subgroup analysis, risk factors for FTR ≥ moderate were evaluated by multiple logistic regression analysis. The risk factors identified in the multivariable risk factor analysis were diastolic RVV (odds ratio 1.083 [95% confidence interval 1.029-1.139]) and systolic RVV (odds ratio 0.951 [95% confidence interval 0.906-0.997 ]).
Conclusions: TAA, TAC, RVV, and the distance between the tips of the anterior and posterior papillary muscles measured on contrast-enhanced CT were shown to be significantly increased in the TR ≥ moderate group. Detailed morphological assessment of FTR is possible by contrast-enhanced CT.