| Aneurysm has been a research focus as a common and dangerous cardiovascular and cerebrovascular disease, especially the treatment of complicated aneurysms. In recent years, interventional cardiovascular catheterization was widely applied to clinical. Due to the advantages of simple operation, small trauma, low cost and faster recovery and so on. However, the complications may happen to complex aneurysms, such as displacement of the stent and the coil fall off from the aneurysm. The catheter of RFA(Radiofrequency ablation) reaches to the heart, kidneys and other locations from the neck and release radiofrequency current, ablates the "focus" by once, and quick cures arrhythmia.The subject combined invasive hyperthermia methods with the mechanism of embolization and proposed a new method for treating aneurysms. The method was made the blood clot rapidly by using RFA, that leads to diminish the blood ?ow in the aneurysm sac and promote the formation of intraluminal thrombus, to shrink the aneurysm and achieve the purpose to cure aneurysm.This study adopted two methods to prove the feasibility of treating aneurysm, including FEM by the software of Comsol Multipysics and the method of vitro model experiment. In numerical simulation, 2D and 3D model were used to analyzing the influence of the different treatment parameters(including different position of electrode, the intensity of electric field) to the temperature field and flow field, which was analyzed whether the temperature field appropriates for the treatment of aneurysms.In the model of the three-dimensional straight aneurysm, the temperature field appeared approximately as a circle which fills the whole arterial aneurysm sac with the intensity of electric field 15V/mm and ablation time 200 s. The maximum temperature was 101.52℃, 60℃ profile contained the most of the aneurysm. A small damage was appeared in the left of the tissue which was contained by the 60℃ profile. When it had electrode, on the upstream, the blood flow increased about 0.04m/s, on the side of no electrode downstream, blood flow reduced about 0.1 m/s. The low flow velocity in the aneurysm was benefit to make the temperature of aneurysm sac to rise. Both the temperature field and flow field proved the feasibility of RFA of treating aneurysm.In addition, an ideal 3D model was established by a 3D printer. And a silica gel transparent model was made by using second reverse mould. Adopting to a circulation system, experiment used in vitro model to observe the rise of aneurysms temperature. Research showed that when the electrode was under the arterial aneurysm orifice, the temperature rose a little. When the power was set at 40 W and 60 W under the same ablation time of 5min, the temperature rose about 1.6 ℃. At 80 W and 5min, the temperature rise about 4℃. When antenna was in the middle of the arterial aneurysm sac, the temperature rosed rapidly in the aneurysm sac. At the three different powers with the ablation time of 5min, the temperature rose about 11℃, the rise of temperature was obvious which benefits the RFA of aneurysm.This study shows that the method of RFA is suitable for treating quasi-circular aneurysm and when it’s set as 15V/mm with the ablation time of 200 s, the temperature field not only can cover the whole aneurysm with small external tissue damage but also can little affect hemodynamic status within the artery, which can be the optimal treatment parameters. Combining RFA with stents, it’s effective to treat aneurysms which have curve parent artery or have saccular aneurysms. |
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