Tricuspid regurgitation is common in patients with severe left heart diseases, such as degenerative mitral regurgitation. However, the evidence base is insufficient to inform a decision about whether to perform concomitant tricuspid-valve repair during left heart surgery in patients who have mild tricuspid regurgitation. To inform decision making, we will conduct a multicenter, randomized trial to assess the benefits and risks of tricuspid-valve repair at the time of left heart diseases in patients with mild tricuspid regurgitation who were undergoing surgery for left heart surgery.

Inclusion Criteria:

1. Patients undergoing left heart valve surgery with mild tricuspid regurgitation;
2. Patients aged 18-80 years;
3. Agree to participate in this study and sign the informed consent form.

Exclusion Criteria:

1. Infective endocarditis within 3 months;
2. Primary tricuspid regurgitation;
3. Isolated tricuspid regurgitation
4. Lactating women and suspected pregnant or pregnant women;
5. Patients with mental disorders, drug and alcohol dependence;
6. Those who participated in other clinical trials one month before the trial;
7. Refusal to participate in this study without informed consent.