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Of 5587 operations for congenital heart disease that we performed between January 1976 and December 1993, 2085 were for correction of ventricular septal defects. Paramembranous, muscular, and atrioventricular canal types were repaired through a right atrial incision, whereas subpulmonary and conus type defects were repaired through a pulmonary artery incision. Circulatory arrest under deep hypothermia was used for patients under 2 years of age or with body weight of less than 10 kg. There were 48 postoperative deaths. The overall mortality was 2.3% and it was related to the age and weight of the patients. The age at which surgical repair was undertaken depended on the position and size of the defect and the degree of intracardiac shunt. Patients with associated pulmonary hypertension underwent surgery before 2 years of age. Early repair of subpulmonary ventricular defects is recommended to prevent aortic insufficiency resulting from valve prolapse. The keys to successful repair were avoidance of a right ventricular incision, improvement of right ventricular function, and postoperative management of pulmonary hypertension. The operative mortality was reduced from 10.14% in the 1970s to 6.43% in the early 1980s by improvements in surgical procedure and postoperative management with a further reduction to 1.25% in recent years, which we attribute partly to the use of a hollow fiber membrane oxygenator.

Mitral valve-related operations are easy to perform and show good results, but to prevent severe thromboembolism or a high ratio of prosthetic valve destruction by tissue, lifetime anticoagulant therapy is essential after the operation. Thus, identifying a new type of surgical procedure and prosthetic valve to cure mitral valve diseases is necessary. Pulmonary valve autograft transplantation (Ross II) with the "top hat" transplantation technique was first reported by Ross DN to cure mitral disease. Because the "top hat" procedure has some shortcomings, we designed the scaffold-pulmonary autograft transplantation procedure and performed animal experiments to confirm the feasibility and effectiveness of the procedure. A total of 13 minipigs, weighing 20-25 kg, were employed as experimental animals to undergo scaffold-pulmonary autograft valve transplantation in our surgical animal lab. The surgical procedure was performed under hypothermic general anaesthesia and extracorporeal circulation (or cardiopulmonary bypass, CPB). Briefly, the chest cave was opened through the left intercostal, the pulmonary valve autograft was harvested during on-pump beating heart, and the pulmonary valve autograft was mounted in a self-made pulmonary valve scaffold and transferred to the mitral valve annulus without removing the mitral instruments. Finally, the outflow tract of the right ventricle was re-established with a pig pulmonary homograft. After finishing data collection, all animals were executed 1 hour after removal from the CPB. For the 13 minipigs that underwent the operation, the CPB time was 182.4 ± 23.4 min. Two of the thirteen cases died of bleeding during the operation and of a post-operative pulmonary embolism, and the remaining eleven survived for one hour. The pressure of the left atrium did not increase significantly (P = 1.00), and the ultrasonic cardiograph (UCG) showed good function of the new mitral valves, with mean ejection fraction (EF) values of 63.6%. The mitral valve orifice areas were 1.10 ± 0.13 cm(2) (pre-operation) and 1.01 ± 0.08 cm(2) (post-operation) (P = 0.013). The function and structure of the new mitral valves were normal. We preliminarily consider scaffold-pulmonary autograft valve transplantation to be a new alternative to cure mitral valve disease, but advanced chronic animal experiments will be needed to confirm the long-term results of the operation. The results showed it could be a new alternative to cure mitral valve disease.

The physical properties of the tissues are weakened after decellularization, and the exposed collagen fibers are prone to thrombogenesis. Several studies have proven that the use of carbodiimide (EDC) as a cross-linking agent can improve the properties of decellularized xenogeneic scaffold materials. We adopted EDC for the treatment of porcine pulmonary arteries in an effort to improve the physical properties of these arteries following decellularization. Twenty porcine pulmonary arteries were randomly divided into 3 groups. The control group (group A) consisted of fresh porcine pulmonary arteries with no further processing; group B was treated with trypsin and the detergent Triton X-100 to remove cells; and group C was cross-linked with EDC after trypsin and Triton X-100 treatment, as in group B. The pulmonary arteries were assessed based on water content, thickness, tensile strength, and thermal shrinkage temperature, to evaluate the physical properties of all of the samples. The scaffolds were then subcutaneously embedded in rabbits. These constructs were removed after 4 weeks and checked. The cells and matrix components of the arterial walls were removed and the fibrous scaffolds were retained. In group B, the moisture content of the pulmonary arterial walls was increased; and the thickness of the walls and the tensile strength of the pulmonary arteries were decreased in comparison with group A. In subcutaneous embedding of the group B samples in rabbits, after 4 weeks, fibroblasts had grown into the scaffolds and regenerated the tissue. The water content was decreased in the pulmonary arterial walls, there was an increase in the tensile strength and the thermal shrinkage temperature in group C compared with group B. The EDC-based cross-linking procedure can enhance the tensile strength of decellularized pulmonary arteries and decrease scaffold rejection and degradation and promote tissue regeneration in vivo.