Objective To study and test novel hybrid valves in vitro and in vivo, and provide basis for clinical use in future. Methods The hybrid valves were fabricated from decellularized porcine aortic valves coated with poly (3-hydroxybutyrate-co-3hydroxyhexanoate, PHBHHx).（1）In the mechanical test in vitro, the uniaxial tensile biomechanics test of the fresh (n=12), uncoated (n=12) and hybrid valve leaflets (n=12) were investigated. (2）In study in vivo, hybrid valves(n=5) implanted in pulmonary position in sheep without cardiopulmonary bypass. Uncoated grafts (n=5) used as control. The specimens of the hybrid or uncoated valve in sheep were explanted and examined by scanning electron microscopy, histology, calcium content and immunofluorescence staining 18 weeks after surgery. Results The mechanical test in vitro revealed that coating with PHBHHx increased maximal tensile strength of hybrid valves compared with the fresh and uncoated state (P＜0.05). The results in vivo indicated the hybrid valves maintained original shape and softness. Immunofluorescence staining for CD31 confirmed that the surface of hybrid valve was covered by confluent CD31+ cells.The interstitium of hybrid valve indicated that smooth muscle actin (SMA)+ cells population were similar to native valvular tissue. The calcium content of hybrid valve was significantly lower than that of uncoated valve leaflets (P＜0.05). Conclusion Decellularized porcine aortic valves coated with PHBHHx have good biological and biomechanical characteristics. The hybrid valve may provide superior valve replacement with current techniques.
Objective To investigate the impact of three kinds of palliative operation on the body and growth of pulmonary artery in patients with congenital heart diseases of diminutive pulmonary blood. Methods Clinical data was reviewed in 28 cases of congenital heart diseases with diminutive pulmonary blood who had been performed cavopulmonary connection （n = 9）, systemic-pulmonary shunt （n = 8 ）, and palliative reconstruction of right ventricular outflow tract （n=11）. The period between re-hospitalized and the first was 5-54 months （19.07±10. 06 months ）. Hematocrit （HCT）, hemoglobin （Hb）, percutaneous oxygen saturation （SpO2）, body surface area （BSA）, and pulmonary artery index （PAI） etc. were observed both before palliation and before the second operation. Results After the second hospitalization, there were 7 cases of death from hemorrhage, failure of circulation and extracorporeal circulation accident etc. The time of respirator, intensive care unit and total amount of dopamine in patients of palliative reconstruction of right ventricular outflow tract were longer and more than those in patients of cavopulmonary connection （P〈0. 05）. HCT, Hb before the second operation were decreased than thoes before palliative operations in all patients, SpO2, BSA and PAI increased significantly （P 〈 0. 01 ）. Before the second operation, BSA of patients with cavopulmonary connection, BSA and PAI of patients with systemic-pulmonary shunt, SpO2, BSA and PAI of patients with palliative reconstruction of right ventricular outflow tract were increased than those before palliative operations（P〈0. 01）. HCT of palliative reconstruction of right ventricular outflow tract was decreased（P〈0. 05）. Conclusion This results suggests that pulmonary blood of patients with congenital heart diseases of diminutive pulmonary blood can be increased, development of pulmonary arteries can be improved efficiently by systemic-pulmonary shunt and palliative reconstruction of right ventricle outflow tract, but it can not be found in cavopulmonary connection patients.
Objective To investigate the optimal timing for surgical treatment of infants less than six months of age with tetralogy of Fallot (TOF), and to improve surgical results and reduce early mortality. Methods Clinical material of 108 consecutive patients with TOF who were less than six months of age undergoing early surgery from Oct.1996 to Dec. 2006 were retrospectively reviewed. There were 70 males and females with mean age of 4.70 months (9 d-6 months). 104 patients underwent complete repair and four patients underwent BlalockTaussig (B T) shunt. Emergency procedures have been performed in 5 patients. Results Five patients (4.63%) died of low cardiac output syndrome (3 patients), pulmonary infection and acute respiratory distress syndrome (1 patient), and acute necrotizing enteritis (1 patient).82 patients were followed up, followup period was 31.17±40.00 months.21 patients lost to followup. One patient(0.92%) required additional intervention for pulmonary valve stenosis 6 months after operation. Heart functional class(New York Heart Association) recovered toⅠ-Ⅱgrading in other patients. Echocardiography shows: no residual ventricular shunt, no stenosis in right ventricular outflow tract and pulmonary valve, pressure difference≤50 mm Hg. No late deaths. Conclusion Early definitive repair of TOF can be performed safely on infants less than six months of age, the results of low mortality is acceptable.
Objective To explore morphological recellularization level of bioprosthetic valve scaffold (BVS) and to provide researching means for fabricating tissue engineered heart valve in vitro.Methods The homograft bioprosthetic aortic tube valve was selected as BVS, which was conserved by liquid nitrogen, and its endothelial cells (ECs) were removed by 0.1% sodium dodecylsulphate (SDS). As implantation cells, the endothelial cells (ECs) differentiating from human bone marrow mesenchymal stem cells (MSCs) in vitro were implanted with high-density seeding (gt;10 5 cells/cm2) on the BVS, which was covered by fibronectin (80 μg/ml) in advance. The complex structure was statically cultured in DMEM (high glucose) with 20% FBS and VEGF (10 ng/ml) for about 20 days in vitro and stained by 0.5% AgNO3. The morphological structure was observed and photographed by stereomicroscope to detect the recellularization level. Results The ECs of the bioprosthetic valve were notonly removed completely, but also the collagen fiber and elastic fibers were reserved. The ECs differentiating from MSCs were successfully implanted on the HBS, whose recellularization levels on 7th, 14th and 20th day were 73%, 85%, and 92% respectively. Conclusion AgNO3 staining technique is effective, convenient, and economic in evaluating the recellularization level of BVS. It is an effective method in morphological observation for fabricating tissueengineered heart valve in vitro.
Abstract: Objective To examine the cell viability and hemodynamic functions of the stented homograft valves preserved in liquid nitrogen. Methods Cell viability of the stented homograft valve preserved in liquid nitrogen after 3 months of preservation (experimental group，n=6) was examined using flow cytometer. Fresh homografts served as control group (n=6). We prepared three sorts of stented homograft valve(21#, 23#, 25#) preserved by liquid nitrogen. In vitro pulsatile flow tests were performed on valves of two groups. Effective opening area EOA),transvalve pressure gradient and regurgitation ratio were recorded at various flow volume, and compare with Perfect bioprosthetic valve. Results The results revealed that the death ratio of endothelial cell was 10.24%±1.71% in the experimental group, and 9.09%±2.72% in the control group (P=0.441). The death ratio of smooth muscle cell was 8.76%±1.82% in the experimental group, and 7.84%±0.59% (P=0.178) in the control group. The death ratio of total cell was 8.79%±1.44% in the experimental group, and 7.40%±0.49% in the control group (P=0.072). There were no significantly differences between two groups. The transvalve pressure gradient of two groups of valve depended on the flow volume, and increased with the flow volume increasing. The transvalve pressure gradient of the stented homograft valve was higher than that of Perfect valve. Regurgitation ratio of the stented homograft valve was bigger than Perfect valve’s. EOA had an increasing character when flow volume increased. EOA of the stented homograft valve was smaller than that of Perfect valve’s. Conclusion Liquid nitrogen can offer the benefit of cell viability of the stented homograft bioprosthetic valves. The stented homograft valve has salisfactory hemodynamic functions.
Abstract: Objective To analyze the surgical treatment of tetralogy of Fallot (TOF) with anomalous coronary artery (ACA) crossing the right ventricular outflow tract (RVOT), in order to improve the outcome of the disease. Methods The clinical data of 26 patients of TOF with ACA crossing the RVOT of Fu Wai Hospital from Oct.1996 to Feb.2006 were analyzed retrospectively. A double ventriculotomy superior and inferior to ACA were used in 11 patients, one ventriculotomy inferior to ACA were used in 6 patients and superior to ACA for 4 patients, 2 patients needed extra cardiac conduits, and 3 patients received other approaches. Results There were 2 operative death （7.7%）and no late deaths. Follow-up was extended 1 to 100 months, all of them had no residual ventricular septal defect(VSD) and their right ventriclepulmonary artery gradient were 27.3±15.6 mmHg. Conclusion Preoperative identification of ACA in patients with TOF is necessary. The surgeon should be careful in inspection of distribution of coronary artery during operation, and undergo the individualized surgical procedures based on the extent of RVOT obstruction and distribution of the ACA.