Objective: To construct a CT scan-based finite element model of thoracic aortic dissection and numerically simulate its hemodynamic profiles, so as to provide a theoretical basis for the hemodynamic mechanism study and clinical management of thoracic aortic dissection.
Methods: Based on the patient-specific CT data of thoracic aortic dissection, the optimized surface model of thoracic aortic dissection was constructed by using the image processing software (MIMICS 13.0), which was then imported into ANSYS 11.0 for finite element mesh dividing. The hemodynamic analysis of thoracic aortic dissection was finally performed by ANSYS CFX 11.0 softeare.
Results: A finite element model for hemodynamic analysis of patient-specific thoracic aortic dissection was successfully constructed. The distribution and changes of streamlines, velocity vector, pressure and wall shear stress were obtained for the patient-specific model.
Conclusions: This model has digital and patient-specific features and can be used to analyze the hemodynamics and mechanism of rupture of thoracic aortic dissection.

Objective: To investigate the impact of intravenous combination chemotherapy with 5-fluorouracil (5-FU) and cisplatin (DDP) on prosthetic vascular grafts in dogs.
Methods: The model of reconstruction of abdominal aorta using ePTFE prosthetic vascular graft was established in 12 dogs, which were equally randomized into chemotherapy group and control group. The chemotherapy group underwent intravenous combination chemotherapy with 5-FU (10 mg/kg) and DDP (1 mg/kg) once daily for 5 days during the 2nd week after operation, and the control group received transfusion with an equivalent volume of vehicle. Physiological parameters of the dogs during the period of intervention were recorded. Graft specimens from five levels were harvested at the 4th week after chemotherapy or vehicle transfusion (6th week after operation) to determine the intimal thickness, CD34 and proliferating cell nuclear antigen (PCNA) expression.
Results: One death (1/6) occurred in chemotherapy group and none (0/6) in control group. Two cases (2/5) in chemotherapy group developed a small amount of mural thrombus formation in prosthetic vascular graft, but that was not found (0/6) in control group. Between-group comparison results were as follows: No statistical difference was noted in intimal thickness of prosthetic vascular graft between the two groups (P＞0.05); the CD34+ cell ratio on the middle segment of prosthetic vascular graft of chemotherapy group was significantly lower than that of control group (P＜0.05), while the CD34+ cell ratio on other levels of prosthetic vascular graft showed no statistical difference between the two groups (P＞0.05); the PCNA expression of intimal area had no statistical difference between the two groups (P＞0.05). Within-group comparison results were as follow: The intimal thickness and CD34+ cell ratio on middle segment of prosthetic vascular graft were all lower than those on anastomotic stomas (P＜0.05 or P＜0.01); the PCNA expression levels of the proximal stomas were all higher than those of the distal stomas (both P＜0.05), and the PCNA expression levels in both sides of stomas were all higher than those of the middle segment of prosthetic vascular grafts (both P＜0.05).
Conclusions: Postoperative intravenous combination chemotherapy with 5-FU and DDP given during the 2nd week after prosthetic vessel replacement has transient retardant effect on the endothelial coverage of the middle segment of prosthetic vascular graft, resulting in the increased incidence of mural thrombus formation of prosthetic vascular graft. However, it has no significant influence on anastomotic healing, and does not increase the incidence of infection or rupture of the graft.

Objective: To investigate the therapeutic effect of the combination treatment of bone mesenchymal stem cells (BMSC) and hepatocyte growth factor (HGF) gene therapy on limb ischemia of rabbits. Methods: Ischemic model of hind limb was induced in the right hind limb of 32 New Zealand rabbits by ligation of the deep femoral artery and complete excision of the superficial femoral artery. After the model was established, the rabbits were equally randomized into empty plasmid treatment group (control group), BMSC treatment group (BMSC group), HGF gene therapy group (HGF group) and BMSC treatment plus HGF gene therapy group (BMSC+HGF group). All treatment regimens were administered by direct intramuscular injection into the operated limb. The collateral vessel count was performed using angiography 28 days after treatment, and the expression of CD31 and HGF in the muscle tissues surrounding the injection sites was detected by immunohistochemical staining and Western blot analysis respectively, 30 days after treatment. Results:The collateral vessel count showed no statistical difference in BMSC group or HGF group compared with control group, but it increased significantly in BMSC+HGF group compared with other 3 groups (P＜0.05 or P＜0.01). The immunohistochemical staining showed that the CD31 expression level of all the treated groups was significantly higher than that of the control group (P＜0.05 or P＜0.01), and CD31 expression had no significant difference between BMSC group and HGF group, but both of which were significantly lower than that of BMSC+HGF group (both P＜0.05). The Western blot demonstrated that the HGF expression level of all the treated groups was significantly higher than that of the control group (P＜0.05 or P＜0.01), and it was increased in the order of BMSC, HGF and BMSC+HGF group that all had statistical differences (all P＜0.05). Conclusions: The combination treatment with BMSC and HGF gene therapy has synergistic effect that can effectively promote collateral vessel development, and thereby improve the perfusion of the ischemic limb of rabbit.