Author + information
- 1Department of Cardiology Internal Medicine, Nanlou Branch of Chinese PLA General Hospital, Beijing, P.R.China
- 2National Key Laboratory of Complex System Intelligent Control and Decision, School of Automation, Beijing Institute of Technology, Beijing, P.R
- 3Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, UK
Percutaneous myocardial laser revasculariztion (PMLR) is a kind of new percutaneous coronary intervention based on transmyocardial laser revascularization (TMLR). The basic principle of PMLR is to improve the circulation status of ischemia myocardium by laser myocardial revascularization. The study was aimed to investigate the optimal strategy of PMLR treatment for chronic ischemic heart disease.
The study firstly introduced the characteristic of laser transmission in myocardium including photon reflection, absorption and scattering. Then, the states of photons at the emission, transmission and disappearance stage, the processes of photon's weight decay and the change of photon's movement step and direction were described and simulated by using Monte-Carlo method. All of the above were simulated by MATLAB, and the relationships between different optical property parameters and therapeutic parameters were discussed. And quantitative analysis of the heat injury range during punching process was also done according to Arrhenius equation, and the model of thermal damage was built. Finally, a “Clinical intelligent PMLR operation platform” and a “Monto Carlo simulation of photon transport operation platform” were designed and compiled by using C++ language.
In the simulation process of the transmission of photo in the myocardium using Monte Carlo method, the myocardium, which was with larger absorption coefficient and big scattering coefficient but smaller anisotropic coefficient, had higher energy due to myocardial absorption of more photons. When the scattering coefficient was 120.00cm-1, and the absorption coefficient was 5.00cm-1, the anisotropic coefficient is 0.90, the optimal aperture of photo distribution was 0 to 1200μm, and the maximum depth of photon transmission was about 1800um in the myocardium. The depth of the channel increased with longer drilling time, and the deepening rate was large at the beginning of drilling, but gradually decreased. Similarly, when the cardiac absorption coefficient was fixed, and the drilling time was less than 0.2, the broaden rate of the aperture was faster, but gradually tended to be stable. When the laser drilling time was fixed, the aperture of the channel was negatively correlated with the depth. After the total blood perfusion required by the ischemic myocardium was quantitatively assessed, a “Clinical intelligent PMLR operation platform” was established by using the grid cardiac reconstruction method, which was used to stimulate a drilling scheme.
The characteristic of laser transmission in myocardium described by Monte-Carlo method, the relationships between different optical property parameters and therapeutic parameters simulated by MATLAB and “Clinical intelligent PMLR operation platform” software help design surgical strategy of PMLR, which ensures sufficient myocardial perfusion, minimum drilling numbers, uniform channel distribution and minimum myocardial thermal damage.