Aim:To correlate anatomic and genetic features of paediatric patients with pulmonary atresia,ventricular septal defect(VSD) and multiple aortopulmonary collateral arteries with surgical outcome. Methods:44 consecutive...Aim:To correlate anatomic and genetic features of paediatric patients with pulmonary atresia,ventricular septal defect(VSD) and multiple aortopulmonary collateral arteries with surgical outcome. Methods:44 consecutive patients aged 33±40 mo underwent either primary one-stage unifocalization (n =32)-or palliative right ventricular outflow tract reconstruction (n=12) followed by secondary unifocalization and repair (n =10)-based on preoperative morphometric and functional evaluation of pulmonary blood sources. Chromosome 22q11.2 microdeletion occurred in 41%of cases. Combined VSD closure during one-stage procedures was guided by an intraoperative pulmonary flow study. Complete repair was accomplished in 35 cases (83%,95%CI 72-95%). Variables examined included occurrence of confluent intrapericardial pulmonary arteries,central pulmonary arteries,confluent intraparenchymal pulmonary arteries,dominant collateral or pulmonary arteries,and chromosome 22q11.2 microdeletion. The sensitivity and specificity of the pulmonary flow study in predicting postoperative pulmonary haemodynamics were also tested. Results:Eight year actuarial survival and freedom from reoperation were 85%and 63%,respectively. Sensitivity and specificity of the pulmonary flow study were 94%and 100%,respectively. None of the anatomical variables examined was significantly related to the outcome of treatment. The only statistically relevant association was detected between survival and occurrence of 22q11.2 microdeletion (p < 0.003). Logistic analysis showed an increased likelihood of positive outcome in relation to first-(p< 0.02) or second-stage (p < 0.04) complete correction. Conclusion:Morphology of pulmonary blood supply has no major impact on surgical outcome. Pulmonary flow study is a highly specific and sensitive intraoperative test. Chromosome 22q11.2 microdeletion remains the only variable significantly affecting survival.展开更多
The concentration and orientation of fiber in a turbulent T-shaped branching channel flow are investi-gated numerically. The Reynolds averaged Navier-Stokes equations together with the Reynolds stress turbulent model ...The concentration and orientation of fiber in a turbulent T-shaped branching channel flow are investi-gated numerically. The Reynolds averaged Navier-Stokes equations together with the Reynolds stress turbulent model are solved for the mean flow field and the turbulent kinetic energy. The fluctuating velocities of the fluid are assumed as a random variable with Gaussian distribution whose variance is related to the turbulent kinetic energy. The slender-body theory is used to simulate the fiber motion based on the known mean and fluctuating velocities of the fluid. The results show that at low Reynolds number, fiber concentration is high in the flow separation regions, and fiber orientation throughout the channel is widely distributed with a slight preference of aligning along the horizontal axis. With increasing of Re, the high concentration region disappears, and fiber orientation becomes ho-mogeneous without any preferred direction. At high Reynolds number, fiber concentration increases gradually along the flow direction. The differences in the distribution of concentration and orientation between different fiber aspect ratio are evident only at low Re. Both Re and fiber aspect ratio have small effect on the variance of orientation angle.展开更多
文摘Aim:To correlate anatomic and genetic features of paediatric patients with pulmonary atresia,ventricular septal defect(VSD) and multiple aortopulmonary collateral arteries with surgical outcome. Methods:44 consecutive patients aged 33±40 mo underwent either primary one-stage unifocalization (n =32)-or palliative right ventricular outflow tract reconstruction (n=12) followed by secondary unifocalization and repair (n =10)-based on preoperative morphometric and functional evaluation of pulmonary blood sources. Chromosome 22q11.2 microdeletion occurred in 41%of cases. Combined VSD closure during one-stage procedures was guided by an intraoperative pulmonary flow study. Complete repair was accomplished in 35 cases (83%,95%CI 72-95%). Variables examined included occurrence of confluent intrapericardial pulmonary arteries,central pulmonary arteries,confluent intraparenchymal pulmonary arteries,dominant collateral or pulmonary arteries,and chromosome 22q11.2 microdeletion. The sensitivity and specificity of the pulmonary flow study in predicting postoperative pulmonary haemodynamics were also tested. Results:Eight year actuarial survival and freedom from reoperation were 85%and 63%,respectively. Sensitivity and specificity of the pulmonary flow study were 94%and 100%,respectively. None of the anatomical variables examined was significantly related to the outcome of treatment. The only statistically relevant association was detected between survival and occurrence of 22q11.2 microdeletion (p < 0.003). Logistic analysis showed an increased likelihood of positive outcome in relation to first-(p< 0.02) or second-stage (p < 0.04) complete correction. Conclusion:Morphology of pulmonary blood supply has no major impact on surgical outcome. Pulmonary flow study is a highly specific and sensitive intraoperative test. Chromosome 22q11.2 microdeletion remains the only variable significantly affecting survival.
基金Supported by the Major Program of the National Natural Science Foundation of China (No.10632070).
文摘The concentration and orientation of fiber in a turbulent T-shaped branching channel flow are investi-gated numerically. The Reynolds averaged Navier-Stokes equations together with the Reynolds stress turbulent model are solved for the mean flow field and the turbulent kinetic energy. The fluctuating velocities of the fluid are assumed as a random variable with Gaussian distribution whose variance is related to the turbulent kinetic energy. The slender-body theory is used to simulate the fiber motion based on the known mean and fluctuating velocities of the fluid. The results show that at low Reynolds number, fiber concentration is high in the flow separation regions, and fiber orientation throughout the channel is widely distributed with a slight preference of aligning along the horizontal axis. With increasing of Re, the high concentration region disappears, and fiber orientation becomes ho-mogeneous without any preferred direction. At high Reynolds number, fiber concentration increases gradually along the flow direction. The differences in the distribution of concentration and orientation between different fiber aspect ratio are evident only at low Re. Both Re and fiber aspect ratio have small effect on the variance of orientation angle.
