Hypertrophic Obstructive Cardiomyopathy With Mitral Regurgitation

ObjectiveHypertrophic cardiomyopathy(HCM)is a kind of genetic cardiomyopathy,with the asymmetry of the interventricular septum hypertrophy as basic characteristic.The pathophysiological changes of HCM are systolic anterior motion(SAM)of mitral valve and dynamic left ventricular outflow tract obstruction(LVOTO).As the existence of LVOTO,HCM is divided into two groups-hypertrophic obstructive cardiomyopathy(HOCM)and non-obstructive HCM.Surgical thearpy is considered to be the gold standard to relieve intractable LVOTO.But whether performing concomitant mitral valve surgery to solve mitral regurgitation(MR)has been controversial..The aim of this study was to investigate the risk factors of HCM with MR and evaluate the effectiveness and safety of different surgical treatment to HOCM with MR.MethodsWe conducted a retrospective cohort study involving patients who was diagnosed as HCM in our clinical center from May 2009 to December 2016.A total of 86 patients were enrolled in the study,including 66 cases of surgery patients.The first part of this study was to collect preoperative clinical data and transthoracic echocardiography(TTE)data and use orderly multivariate logistic regression model analysis,screening independent risk factors for MR in 86 cases of HCM patients.In the second part of the study,according to the grade of MR,66 cases of surgical patients were divided into 2groups: mild MR or below group(n = 20),MR moderate or above group(n = 46).Each group was divided into three subgroups: Isolated Morrow procedure group,extended Morrow procedure concomitant with mitral valvuloplasty(MVP)group and extended Morrow procedure concomitant with mitral valve replacement(MVR)group.Postoperative and follow-up of TTE changes were evaluated at different MR grade to analysis the effectiveness of the three operations.Then all surgery patients were divided into non-MVR group(n = 29)and MVR group(n = 37)according to whether or not concomitant MVR was performed,and then 1: 1 propensity score matching(PSM)(matched 29:29)was applied to eliminate the bias.The incidence of complications,cardiac function and the survival free from primary end points and secondary end points were compared from perioperation to medium-term(2～92 months to follow up,the median follow-up time of 19(10,44.5)months).Results1.Through orderly multivariate logistic regression model analysis,it was found that the basal obstruction(OR:12.01,95%CI:2.05-70.45),SAM(OR:1.78,95%CI:1.52-5.34),and mitral valve abnormalities(anterior leaflet OR:3.12,95%CI:0.92-5.70;posterior leaflet OR:8.76,95%CI:2.71-28.34)were the independent risk factors for HCM with MR.2.At the different grade of MR,Isolated Morrow procedure,extended Morrow procedure concomitant with MVP and extended Morrow procedure concomitant with MVR could significantly reduce left ventricular outflow tract pressure gradient(LVOTPG),eliminate SAM and improve MR.While it was found that extended Morrow procedure concomitant with MVR achieved the best LVOTPG remission rate,with no postoperative residual MR.3.The perioperative mortality of overall patients was 3%,while perioperative mortality of MVR group was 5.4%,compared with 0 of non-MVR group,with no significant difference(P>0.05).There was no significant difference in the incidence of postoperative and long-term complication and postoperative cardiac function between the two groups(P> 0.05).4.After PSM,the survival possibility free from the primary end points at 6,12,36 months after surgery was 89%,89%,83% in MVR group and 100%,93%,93% in nonMVR group respectively,and there was no significant difference(P>0.05).The survival possibility free from the secondary end points at 6,12,36 months after surgery was 93%,89%,80% in MVR group and 89%,83%,83% in non-MVR group respectively,with no significant difference(P> 0.05).ConclusionsIt was found that the basal obstruction,SAM and mitral valve abnormalities were independent risk factors of HCM with MR.Isolated Morrow procedure,extended Morrow procedure concomitant with MVP and extended Morrow procedure concomitant with MVR could effectively relieve LVOTO and abolish SAM.The patients undergoing extended Morrow procedure concomitant with MVR required lifetime anticoagulation.Medium-term effectiveness of concomitant MVR was not inferior to that of the procedure preserving valve structures.However,long-term outcome needed further follow-up.