Background: The etiology of tricuspid and mitral valve regurgitation (TR and MR) after heart transplantation is still controversial.
Methods: We studied 25 patients undergoing transplantation and intraoperative transesophageal echocardiography to evaluate the incidence, the degree, and the cause of TR and MR. The degree of valve regurgitation was assessed by color Doppler echocardiography. Cross-sectional areas of the recipient (R) and donor (D) portions of the atria and their ratio (R/D) were measured to assess the distortion of atrial geometry. Tricuspid and mitral valve annuli, their systolic shortening, and hemodynamic indices were measured preoperatively and perioperatively.
Results: Tricuspid valve regurgitation was found in 21 of 25 patients (84%) and MR in 12 of 25 (48%). The degree of MR was mild, whereas TR was mild to moderate. Mitral valve regurgitation did not show any correlation with the studied indices; TR showed no correlation with the hemodynamic indices but a significant correlation with R/D ratio (r = 0.90; standard error of the estimate = 0.2). An inverse correlation was found between the degree of TR and systolic shortening of tricuspid annulus (r = -0.88; standard error of the estimate = 0.03) and between R/D ratio and systolic shortening of tricuspid annulus (r = -0.85; standard error of the estimate = 0.04).
Conclusions: Tricuspid valve regurgitation has a higher incidence than MR and occurs immediately after transplantation; MR is mild and correlates with neither hemodynamic indices nor atrial distortion. An increased R/D ratio, and hence distortion of right atrial geometry, may lead to a reduction in systolic annulus shortening, which in turn causes TR. Surgical attempts to reduce the R/D ratio may decrease the incidence and the degree of TR after heart transplantation.