Surgical Managements Of Congenital Mitral Regurgitation(MR)in Children

Background and subjective:Mitral valvuloplasty(MVP)is a preferred option for mitral regurgitation(MR)in children.However,the outcome of MVP is unsatisfactory because of the high incidence of reinterventions after MVP.Meanwhile,MVP is relatively difficult to perform for the various surgical techniques and individualized strategies,and a long learning-curve of MVP is required.In recent years,it has become a hotspot to develop a standardized and reproducible strategy of MVP for congenital MR,which is common in pediatric population.Based on the clinical experience of our team,we have proposed a hypothesis that congenital MR in children is mostly attributed to leaflet mal-coaptation of mitral valve(MV),of which abnormal chordae plays the most important part.This study aims to verify the hypothesis by a small sample prospective observational study and elucidate the rationale and evaluate the outcomes of our standardized strategy of MVP with leaflet(the edge zone of leaflet)plication(LP),rehabilitation of abnormal subvavular structure and posterior annuloplasty as principal techniques by a retrospective study involved in outcomes of 113 patients.Finally,we hope that the standardized strategy of MVP could widely spread around our country.Methods and Results:This study contains 3 parts.First,we have performed a prospective observational study to preliminarily verify our hypothesis that poor coaptation of MV leaflets caused by abnormal chordae tendineae connection was a major reason that caused MR in children.In this study,relative leaflet prolapse was defined as the distance between two adjacent chordae tendineae connected to the edge of a leaflet being greater than 4 mm.Abnormal chordae tendineae included mal-connection,short,fusion or absence on the leaflet margin.Based on the findings,we tried to explore a simplified therapeutic strategy,that is,to use same repair techniques against various MV malformation that had similar underlying anatomical abnormalities.The techniques included the aggressive resection of mal-connected chordae tendineae,papillary splitting for the short and fused chordae tendineae,LP for improving the leaflet coaptation and subsequent posterior annuloplasty against annular dilatation and for better coaptation of the leaflets.According to the intraoperative MV inspection and outcomes of a 6-months to 1-year follow-up in consecutive 20 patients,we confirmed the hypothesis and determined that the area of leaflets in almost MR patients is adequate for LP.Then our "three-step" MVP standardized repair strategy was further established,that is,rehabilitation of subvavular apparatus,LP and posterior annuloplasty.Second,we have performed a retrospective study to evaluate the short-mid-term outcomes of 113 patients who underwent the standardized strategy of MVP in our institution.We analyzed our results and compared it with the previously reported results from foreign centers with the incidence of reinterventions of MV as the key issue.Overall,our standardized strategy provided better outcomes,especially a lower incidence of reinterventions.In addition,the 3-step repair techniques in our strategy of MVP was more reproducible and easier to perform,thus making it more in accordance with the definition of "standardization".Last,we have reviewed the latest and advanced research of congenital MR in pediatric population in recent years,including the anatomy and morphology of MV and the surgical management of MR.There is no doubt that MVP will continue to be a preferred option for congenital MR in pediatric population in the future.Hence,the standardized strategies of MVP proposed in this study is promising and will be of great significance in treating congenital MR in the future.Conclusions:The main anatomical abnormality causing congenital MR is the poor coaptation of MV leaflets resulted from abnormal chordae,which existed in the majority of patients with congenital MR.The standardized strategy of MVP established by our center,of which LP was a principal technique,was safe and effective with a low incidence of reinterventions and favorable short-mid-term outcomes.