Changes in the degree of tricuspid regurgitation after surgery and risk factors for failure - Significant tricuspid regurgitation (TR) is frequently present in patients undergoing mitral valve surgery concomitant with tricuspid valve repair and and tends to increase over time, the rate of moderate or higher postoperative TR at 1 - 3 weeks, 1 - 3 months and 6 - 12 months is 23.5%, 30% and 32.3% respectively (the rate of severe TR were 1%, 2.5%, and 4.6%, respectively).