체외 고강도 집속 초음파를 이용한 CTO 융해에 관한 연구

Abstract

The coronary artery diseases such as angina and myocardial infarction are increasing as the diet become carnivorous. Those cardiovascular disorder are mainly caused by occlusion. The atherosclerosis can make thrombus which is the final product of the blood coagulation step in hemostasis, and it can be stacked developed in relatively narrow and winding coronary artery. As the thrombus become bigger, that plaque like material may occlude the coronary artery completely, which is defined as CTO(Chronic Total Occlusion). The surgical operations such as coronary artery bypass graft(CABG) and percutaneous coronary intervention(PCI) are usually performed to treat CTO. However, CABG has limitation, risk of significant surgical mortality rate, expense, and long recovery period. Comparing the CABG, the PCI is simpler than CABG, in this reason PCI is widely operated in Asia countries such as Japan and Korea. In the PCI the guide wire technique of surgeon is the key operation for finding true lumen through the totally occluded artery. The operation success rate is totally depending on surgeon’s skill, sense and decision from the X-ray angiography. Especially, the treatment of the CTO in winding coronary artery region is very difficult takes a lot of operation time. In this paper, The basic research was carried out to melt the CTO by high-intensity focused ultrasound, which is applied to the intravascular therapeutic microrobot. COMSOL multiphysic software is used to simulate the sound pressure distribution and the deformation of specimen. The chalk as the phantom material and which is composed of CaCO3, the transducer with 5.4MHz are used for the experiments. The specimen is fixed by the 3-axis stage and the ultrasound is irradiated after the transducer moves to the focal point. As a result of experimental data, it was confirmed that the surface of the specimen of CTO was dissolved well.