ABSTRACT
Objective To explore the biomechanical mechanism of aortic insufficiency (AI) after single aortic valve replacement (SAVR) in children and propose the corresponding countermeasures. Methods The idealized aortic valve model and postoperative growth model were constructed. By changing the length of leaflet free edge, leaflet height as well as improving the design with a concave structure, the effects of different structure dimensions on movement synchronization and closing performance of the aortic valve after surgery were compared. Results The closure of the replacement leaflet lagged behind the autologous leaflet, which fitted 2 mm below free edge of the replacement leaflet. AI occurred 6 years after operation. Increasing leaflet height could not improve the postoperative effect and would increase the maximum stress of the leaflet. Increasing free edge length by 10% could improve the postoperative outcomes, while increasing free edge length by 15% would cause the leaflet to be too long, hence resulting in a poor fit of the aortic valve. Compared with the traditional structure, the concave structure was more beneficial for closing performance of the aortic valve, and it could effectively reduce the maximum stress by 20% with the best effect. Conclusions The leaflet movement will be out of synchronization after SAVR, the point of convergence will be shifted, and AI will appear 6 years after surgery. It is recommended to use a concave structure with free edge length increased by 10%, while increasing leaflet height is not recommended.
ABSTRACT
@#Objective To summarize the experience of right ventricular outflow tract reconstruction with self-made single-valve conduit for the treatment of complex congenital heart disease, and to explore the key points of operation, and to evaluate the short-term and medium-term results of the treatment. Methods We retrospectively analyzed the clinical data of 65 patients with complex congenital heart disease treated by self-made single-valve conduit from January 2006 to June 2018. There were 42 males and 23 females aged 5-23 (9.9±4.2) years with weight 15-65 (26.2±9.9) kg. There were 19 patients with single valve artificial blood vessel (an artificial vascular group), and 46 patients with single valve bovine pericardium tube (a bovine pericardial tube group). There were 48 patients of ventricular septal defect (VSD) with pulmonary atresia (PA), 10 patients of corrective transposition of great artery with pulmonary artery stenosis, 5 patients of tetralogy of Fallot with single coronary artery malformation, 2 patients of double outlet of right ventricle with pulmonary artery stenosis and single coronary artery malformation. Results Two patients died early after operation, both of them were VSD/PA patients who underwent radical treatment of extravascular prosthesis. The right ventricular outflow tract pressure difference was 13-37 (25.2±4.9) mm Hg in the artificial vascular group and 5-23 (10.5±3.3) mm Hg in the bovine pericardial tube group. No obvious reflux was found at discharge. The patients were followed up for 8 months to 13 years. One patient was lost. During the follow-up period, there were 5 patients of moderate tricuspid regurgitation, 32 patients of moderate intraductal regurgitation, 7 patients of severe right ventricular outflow tract obstruction, 11 patients of moderate obstruction and 25 patients of mild obstruction. There was no late death. Heart function classification of all patients was in New York Heart Association classⅠtoⅡ. Conclusion The self-made single-valve conduit used to reconstruct right ventricular outflow tract shows good clinical effect. Using bovine pericardium tube has less pressure difference of outflow tract in comparison with artificial blood vessel. Bovine pericardium tube is more recommended for young and low weight patients.