RESUMO
Objective To investigate the effects of different bypass grafting for treating DeBakey Ⅲ aortic dissection. Methods The patient-specific models of DeBakey Ⅲ aortic dissection based on CT images were reconstructed by using Mimics software, and two bridge models of bypassing between ascending aorta and abdominal aorta (AA), and between left subclavian artery and abdominal aorta (LA) were established by computer-aided method, respectively. Then numerical simulations were performed by using fluid-structure interaction (FSI) method to compare hemodynamic differences of these two models. Results After bypass surgery, the mass flow, mean and maximum velocities of the through lumen models were reduced to different degrees. Meanwhile, both the maximum blood pressures and displacements of the vessel walls of AA models were decreased, but those of LA models were increased. In contrast, all the above-mentioned hemodynamic parameters of the blind lumen models were decreased, especially for AA models. Conclusions The AA bypassing is a better treatment for DeBakey Ⅲ aortic dissection of through lumen and blind lumen. The therapeutic effects can be easily explained through simulation results, to ensure the scientific validity and clinical utility of bypassing.
RESUMO
Objective To investigate the effect on aneurysmal pressure after stent intervention treatment for aneurysm accompanied by stenosis. Methods Computational fluid dynamics (CFD) analyses were carried out to make comparative study on aneurysm models with and without stenosis. Three models (M1, M2, M3) were constructed to compare the pressure variations. M1 was the aneurysm model with no stenosis and no stent, M2 was forming from M1 model with a preaneurysm stenosis, and M3 was the M2 model with stent implantation at the place of the aneurysm. Results For comparison between M2 and M1, pressure increase in the aneurismal sac caused by a mild stenosis (50%) was about 1.399 9 kPa(10.3 mmHg) with the peak systole, and the average pressure increase in a cardiac cycle was about 0.572 kPa(4.3 mmHg). For comparison between M2 and M3, pressure increase in the aneurismal sac was about 1.037 kPa(7.8 mmHg) at peak systole in a cardiac cycle, and the average pressure increase in the aneurismal sac in a cardiac cycle was about 0.399 kPa(3 mmHg). Conclusions A mild stenosis could not result in the sharp pressure increase with stent intervention applied to the treatment of aneurysm accompanied by stenosis harbored on a tortuous intracranial artery. The geometry of the parent vessel and its aneurysmal/stenotic diseases do have influence on the pressure variation at the place of aneurysm.