Experimental And Clinical Research On Individualized Right Ventricular Outflow Tract Reconstruction Of Complex Right Heart System Disease

Objective:This study aims to explore new methods for right ventricular outflow tract(RVOT)reconstruction in complex right heart system diseases.Methods:Experimental and clinical retrospective analysis have been done to evaluate the effects of individualized bi-orifice reconstruction in patients with Tetralogy of Fallot(TOF).Clinical retrospective analysis have also been applied to evaluate the individualized RVOT reconstruction using autologous tissue in situ for the treatment of pulmonary atresia with ventricular septum defect(PA-VSD).Results:.The test of pulmonary valve models on pulse duplicator system showed that bi-orifice reconstruction can reduce pulmonary regurgitation.Clinical results of patients with TOF indicated that the pulmonary regurgitation and re-intervention rate by bi-orifice reconstruction were better than those by TAP method.Clinical results of patients with PA-VSD testified that all patients using autologous tissue as the posterior wall had pulmonary valve regurgitation but within an acceptable range,the ROVT stenosis and the re-intervention rate were improved comparing to patients using bovine jugular vein conduit.Conclusion:Individualized pulmonary valve bi-orifice procedure is a safe and excellent method for reconstructing RVOT in ToF.Individualized RVOT reconstruction with autologous tissue preserved in situ as the posterior wall is a satisfactory method for treating PA-VSD.Part 1 Experimental research on reconstruction of right ventricular-pulmonary artery by bi-orifice methodObjective:This study aims to evaluate the feasibility of establishing an artificial pulmonary valve model on pulse duplicator system,and the anti-regurgitation mechanism of pulmonary bi-orifice for the reconstruction of right ventricular outflow tract in Tetralogy of FallotMethods:The right ventricular outflow tract of pig hearts were obtained,then the pulmonary bi-orifice(observation group,n=10)or the standard trans-annular patch procedures(control group,n=10)to reconstruct the right ventricular outflow tract of Tetralogy of Fallot were imitated on those hearts respectively.Those models were tested on pulse duplicator system to evaluate its anti-regurgitation mechanism by observing pulmonary valve movements.And the regurgitation fraction,transvalve pressure,and effective orifice area of the pulmonary valve of the two groups were detected and compared.Results:During systole,the forward blood flow opens the first and second orifice,passes through the pulmonary valve annulus smoothly.During diastole,coaptation of the pulmonary valve leaflets close the first orifice;the pericardial patch and the separated pulmonary valve move toward each other until they contact each other,the latter is much more notable;the separated pulmonary valve leaflets become flat and more spacious.All those movements account for the closure of the second hole.The pulmonary valve regurgitation fraction in the observation group(6.99±1.38%)was better than that in the control group(18.84±2.25%).The effective orifice area and the transvalve pressure of the pulmonary valve in the observation group(1.06±0.04 cm2,18.3±2.55mmHg)were similar to that in the control group(1.08±0.03 cm2,17.5±2.45mmHg).Conclusion:Pulse duplicator system is a feasible method to test artificial pulmonary valve model;The pulmonary bi-orifice for the reconstruction of the right ventricular outflow tract in patients with Tetralogy of Fallot is an effective and optional method.Part 2 Clinical application of individualized pulmonary bi-orifice for the reconstruction of right ventricular outflow tract in Tetralogy of FallotObjective:The study aims to establish a new method in the T etralogy of Fallot(ToF)called the pulmonary valve bi-orifice method(pulmonary annular sparing with an individualized autologous pericardial patch;thus,two orifices are formed at the level of the pulmonary valve annulus to reconstruct the right ventricular outflow tract(RVOT).Methods:A retrospective analysis of 128 TOF patients from October 2009 to June 2018 with severe pulmonary valve dysplasia who underwent transvalvular annular patch(TAP)procedure(control group)or an individualized pulmonary valve bi-orifice procedure(observation group)were studied.The RVOT for each patient in the observation group was individually reconstructed per the patient’s weight and the size of the autologous pulmonary valve using the bi-orifice method;however,increasing the cross-sectional area of the pulmonary valve annulus without destroying its integrity.The result was then compared to the control group,where TAP procedures were applied to evaluate the short tomid-termoutcome(s).Results:For clinical applications,patients in both groups were compared.The results showed no significant differences in cardiopulmonary bypass and aortic cross-clamp time,mechanical ventilation,and ICU and post-operative residence between the two groups.During the follow-up period(3-to 12-years),4 patients in the observation group had mild regurgitation after surgery(22.2%),while 10 patients had moderate pulmonary regurgitation(15.8%)with no right ventricular(RV)dilation.On the other hand,22 patients(39.6%)had moderate to severe regurgitation in the control group,while left pulmonary artery stenosis occurred in one patient.In the control group,six patients(9.2%)with severe RV dilation were reoperated.Conclusion:Individualized pulmonary valve bi-orifice procedure is a safe and excellent method for reconstructing RVOT in ToF.Part 3 Individualized Right Ventricular Outflow Tract Reconstruction using Autologous Tissue In Situ for the treatment of Pulmonary Atresia with ventricular septum defectObjective:The study aims to evaluate the early and mid-term results of a novel procedure for right ventricular outflow tract(RVOT)reconstruction in Pulmonary Atresia with ventricular septal defect(PA-VSD).Methods:RVOT was reconstructed using autologous tissue preserved in situ as the posterior wall and a bovine jugular vein patch(BJVP)as the anterior wall in patients with PA-VSD(observation group).The size of the BJVP made from a bovine jugular vein conduit(BJVC)was individually calculated using a formula based on the child’s weight and the size of the autologous pulmonary artery(the diameter of BJVCDBJVC=Dtheoretical-((?)z-4)/π.Its effect was then compared with the conventional modified Rastelli procedure based on the bovine jugular vein conduit(control group).Results:A total of 11 patients who underwent the new procedure were simultaneously compared with the 15 patients in the control group.No deaths occurred in both groups.Notably,there were no significant differences in mechanical ventilation,ICU and postoperative residence,cardiopulmonary bypass,and aortic cross-clamp time.In the follow-up,which spanned for 2-8 years,only four patients with moderate regurgitation were noted in the observation group without obstruction.In the control group,two patients developed severe stenosis at 7-days and 7-years after surgery respectively,and had a conduit replacement.three patients suffered from anastomotic stenosis,which was corrected by balloon dilatation.Conclusion:Individualized RVOT reconstruction with autologous tissue preserved in situ as the posterior wall is a satisfactory method for treating PA-VSD.