Abstract: BACKGROUND: Preservation of the subvalvular apparatus in valve replacement surgery remains controversial and there is no uniform and reliable standard for the selection of surgical procedures for valve diseases.
OBJECTIVE: To explore and analyze the effect of valve replacement with preservation of the mitral valve subvalve apparatus to promote effective valve healing.  
METHODS: This study enrolled 68 patients with mitral insufficiency as the main disease combined with or without aortic valve disease, who were admitted to Shiyan Taihe Hospital from January 2018 to December 2018 and underwent mitral valve replacement with preservation of the mitral subvalvular apparatus and mitral valve and aortic valve double valve replacement. There were 11 cases with preservation of the subvalvular apparatus of the full valves, 35 cases with preservation of the subvalvular structure of the posterior valve, and 22 cases with complete resection of the mitral valve and the subvalvular chordae tendineae. Echocardiography review was performed 6 months after operation, and cardiac function indexes such as left atrial end-diastolic diameter, left ventricular end-diastolic transverse diameter, left ventricular ejection fraction, left ventricular short-axis shortening rate, left ventricular inflow tract and outflow tract, valve function, and paravalvular healing were compared among the three groups. Complications within 6 months after surgery were recorded.
RESULTS AND CONCLUSION: The cardiopulmonary bypass time, blocking time, ICU stay time, and postoperative hospital stay in the full-valve subvalvular apparatus preservation group and the posterior subvalvular apparatus preservation group were all lower than those in the mitral valve and subvalvular chordae tendineectomy group (P < 0.05). There were no significant differences in the levels of cardiac function indexes such as left atrial end-diastolic diameter, left ventricular end-diastolic transverse diameter, left ventricular ejection fraction, and left ventricular short-axis shortening rate among the three groups (P > 0.05). The left atrial anteroposterior diameter at the end of diastole and the left ventricular end-diastolic transverse diameter in the full-valve subvalvular apparatus group were obviously lower than those in the other two groups. The left ventricular ejection fraction and left ventricular short-axis shortening rate in the full-valve subvalvular apparatus group were obviously higher than those in the other two groups. The incidence of complications within 3 years postoperatively showed no significant difference among the three groups. To conclude, although there is no significant difference in the effects of mitral valve replacement with preservation of the mitral subvalvular apparatus and double valve replacement of the mitral valve and aortic valve on the cardiac function of patients with mitral insufficiency as the main disease combined with or without aortic valve disease. However, in terms of data structure, valve healing is more obvious in patients undergoing valve replacement surgery with the mitral subvalvular apparatus preserved, which has certain advantages. Moreover, there is no significant difference in the incidence of complications within 3 years after surgery. Therefore, valve replacement surgery that preserves the mitral subvalvular apparatus can promote valve healing, improve recovery time, promote early recovery and discharge, and reduce the economic burden of patients.

Key words: mitral subvalvular apparatus, valve replacement, cardiac function, complication, left ventricular ejection fraction