Abstract: Objective Conventional full sternotomy （CFS） is considered the best treatment for mitral regurgitation （MR）. But the surgical trauma of CFS is great. Minimal invasive （MI） mitral valve （MV） repair for MR through right mini-thoracotomy has been developed to decrease operative trauma; however, the safety and efficacy are not defined yet. In the present study, clinical outcomes were compared between patients with MR who received MI or CFS. Methods The data of 96 patients who mainly suffered from MR during the same period were collected. Among them, 51 patients received CFS （CFS group）, and 45 patients received MI （MI group）. Patients' demographics, surgical data, pre- and post-operative cardiopulmonary parameters were compared between the two groups. Postoperative overall survival, reoperation, and recurrent MR survival were estimated using the Kaplan-Meier method, and comparisons between groups were performed by log-rank test. Results The procedures were successfully performed in all patients. The incision length was significantly shorter in the MI group. Compared with the CFS group, intraoperative blood loss, postoperative blood transfusion, and thoracic drainage were less in the MI group. Atrial fibrillation ablation was performed in the two groups. In the CFS group, a better result of atrial fibrillation ablation was achieved; however, a lower incidence rate of new-onset postoperative atrial fibrillation was observed in the MI group. More pulmonary complications were found in the MI group. The inflammatory response was lighter in the CFS group on post operative day（POD） 1 and 2. On postoperative day 2, the inflammatory response in the MI group reduced significantly. No statistical difference was found in overall survival, reoperation-free survival, and recurrence-free survival. Conclusion The efficacy and safety of MI for MR are the same as CFS. MI could be performed in the vast majority of patients with MR.

Key words: Mitral valve repair, Mitral regurgitation, Minimal invasive, Conventional full sternotomy