Surgical Treatment Results Of Secondary Tunnel-like Subaortic Stenosis After Congenital Heart Disease Operations

Objective To summarize surgical results of secondary tunnel-like subaortic stenosis(STSS)after congenital heart disease(CHD)operations.To explore whether or not to avoid or reduce the incidence of subaortic stenosis after congenital heart disease,analyze the pathogenesis of secondary tunnel-like subaortic stenosis,evaluate the operative effect and prognosis.Methods We analyzed clinical data of 25 patients who underwent surgical repair for secondary tunnel-like subaortic stenosis in Fuwai Hospital from 1st January 2009 to 31st December 2015.There were 17 males and 8 females.The types of congenital heart disease included double outlet right ventricle,ventricular septal defect and partial atrioventricular septal defect,Tetralogy of Fallot and coarctation of aorta et al.There were 12 cases of double outlet right ventricle in the whole group,accounting for 48%of the total group,far higher than the ratio(1.5%)of double outlet right ventricle in congenital heart disease,10 of the 12 patients underwent intraventricular repair,and 2 underwent arterial switch operation,3 cases of coarctation of aorta in all 25 patients,which was higher than the ratio of coarctation of aorta in congenital heart disease(12%VS 5%-8%),2 cases of partial atrioventricular septal defect in all patients,which was higher than the ratio of partial atrioventricular septal defect in congenital heart disease(8%VS 5%),In addition,there were 2 cases of Tetralogy of Fallot,1 case of bicuspid arotic valve,1 case of persistent left superior vena cava,and the percentages were 8%,4%and 4%,respectively.The median age of the patients when they received their first operations for congenital heart disease was 1 year(1 month to 42 years).The median age of the patients when they received tunnel-like subaortic stenosis repair was 5 years and 8 months(2 years and 10 months to 48 years).The surgical types contained modified Konno procedure(10 cases),Konno procedure(1 case),Fibro-muscular resection(11 cases),Removal and reconstruction of the intraventricular baffle(3 cases).We divided the operation into two groups,the Konno procedure group and the non-Konno procedure group.Results All the patients successfully received their tunnel-like subaortic stenosis repair.There was no surgical death in this study.Patients who had symptoms in Preoperative,all their symptoms were disappeared in postoperative.? degree atrioventricular block was occurred in 2 patients after operation and both 2 patients needed to set permanent pacemaker.The preoperative gradient of acrossing the left ventricular outflow tract was(86.7±30.7)mmHg,and the postoperative gradient was(12.4±3.4)mmHg.The gradient of acrossing the left ventricular outflow tract in Konno group decreased from(96.2±30.1)mmHg to(8.2±4.2)mmHg,P<0.05.The gradient of acrossing the left ventricular outflow tract in non-Konno group decreased from(79.1±29.1)mmHg to(15.7±11.2)mmHg,P<0.05.The changes of aortic transvalvular pressure between the two groups was(88.0+31.2)mmHg in Konno group and(63.5+26.8)mmHg in non-Konno group respectively,P<0.05.? degree atrioventricular block was occurred in 2 patients after operation and both 2 patients needed to set permanent pacemaker.All the patients were followed up after discharge for a median duration of 2 years(4 months to 6 years).During follow-up,none of the patients had any clinical symptom or subaortic restenosis,Freedom from recurrent tunnel-like subaortic stenosis at 5 years was 100%,and there was no late death.Conclusions The subaortic stenosis which secondary to the postoperation of congenital heart disease is less common,In particular,tunnel like stenosis is extremely rare.After probing into the cause,we consider that hemodynamic disorder of left ventricular outflow tract,and the formation of turbulence flow,constantly impact on the left ventricular outflow tract,meanwhile,a certain shear stress was generated,resulting in the left ventricular outflow tract fibromuscular hyperplasia.Finally,left ventricular outflow tract stenosis was formatted.As to the treatment,for the tunnel-like subaortic stenosis with normal-sized aortic annulus and normal aortic valve,the modified Konno procedure and resection of the fibromuscular are safe and effective.Foliowing-up to the present,there was no recurrence of aortic stenosis.The improvement of aortic transvalvular pressure of the Konno procedure group was significantly better than that septal fibromuscular resection group.Existing problems include that the incidence of III degree atrioventricular block was slightly higher after the operation(8%,2/25),moreover,The follow-up time was not long enough,long-term needs further observation.