2019 Volume 39 Issue 4 Pages 293-302
Endovenous laser ablation (EVLA) is popular as a less invasive treatment for varicose veins. To reduce undesired side effects, such as postoperative pain and subcutaneous hemorrhage, a semiconductor laser device with a wavelength of 1,470 nm and the ELVeS Radial 2ringTM fiber (CeramOptec, Germany) have been developed. To obtain regulatory approval for such new medical devices in a short period of time and with minimal clinical trials, it is necessary to establish an objective technique for evaluating efficacy and safety in a manner that is not influenced by the operator’s skill. The purpose of this study was to develop a computer simulation model for estimating the intravascular temperature during EVLA and to evaluate the efficacy and safety of the new devices. The simulation was performed under the same irradiation conditions as an ex vivo experiment of EVLA, and validated by comparing the measured and calculated temperatures. When the output power was 7.0 W, the measured peak temperatures were about 90°C and coincided well with the calculated temperatures. On the other hand, when the output power was 10.0 W, the calculated temperatures exceeded 100°C and were higher than the experimental values by 13°C or more. We speculate that the overestimation of the temperature was caused by the latent heat, because vacuolation was observed in the histological images of the venous walls after laser irradiation. Therefore, the results of this simulation are comparable to the measured values. This simulation model should be useful for determining the optimal irradiation condition, and the method of quantitative analysis developed in this study will play a key role in theoretical interpretation of thermal effects during EVLA.
