ObjectiveTo analyze clinical experience and outcomes of bileaflet preservation in mitral valve replace-ment (MVR) for patients with severe mitral regurgitation (MR). MethodsWe retrospectively analyzed clinical data of 17 patients with severe MR who underwent MVR with bileaflet preservation in the Department of Cardiovascular surgery of Guangdong General Hospital from June 2011 to January 2013. There were 14 males and 3 females with mean age of 63.41±11.82 years (range, 38 to 82 years). There were 13 patients with atrial fibrillation. Preoperatively, 5 patients were in New York Heart Association (NYHA) functional class Ⅲ, and 12 patients were in NYHA class Ⅳ. There were 7 patients with ischemic MR, 9 patients with degenerative MR, and 1 patient with rheumatic MR. ResultsMVR with bileaflet preservation was performed for all the patients. Concomitant coronary artery bypass grafting was performed for 4 patients. Eleven patients received bioprosthetic MVR, and 6 patients received mechanical MVR. There was no in-hospital death, postoperative low cardiac output syndrome or left ventricular rupture. All the 17 patients were followed up for a mean duration of 16.44±5.02 months (range, 2 to 25 months). During follow-up, 1 patient died of severe paravalvular leak 2 months after surgery. All the other patients had good mitral valve function. None of the patients had anticoagulation or prosthetic valve related complication. Patient's heart function was significantly improved. Eleven patients were in NYHA functional class Ⅰ, 4 patients were in NYHA class Ⅱ, and 1 patient was in NYHA class Ⅲ. Cardiothoracic ratio, left atrial dimension, left ventricular end-diastolic dimension and left ventricular end-systole dimension postoperatively and during follow-up were significantly smaller than preoperative values. Postoperative left ventricular ejection fraction (LVEF) was significantly lower than preoperative LVEF(50.94%±8.78% vs. 55.31%±10.44%, P=0.04), but LVEF during follow-up was not statistically different from preoperative LVEF(55.31%±10.44% vs. 56.13%±9.67%, P=0.73), and LVEF during follow-up was significantly higher than postoperative LVEF(56.13%±9.67% vs. 50.94%±8.78%, P=0.02). There was no statistical difference between postoperative mitral pressure half-time (PHT)and PHT during follow-up (95.06±19.00 ms vs. 94.56±19.19 ms, P=0.91). ConclusionMVR with bileaflet preservation is a safe and effective surgical technique for patients with severe MR, and can significantly improve postoperative left ventricular remodeling and function.