Mathematical Modeling of Radiofrequency Ablation for Varicose Veins

Abstract

We present a three-dimensional mathematical model for the study of radiofrequency ablation (RFA) with blood flow for varicose vein. The model designed to analyze temperature distribution heated by radiofrequency energy and cooled by blood flow includes a cylindrically symmetric blood vessel with a homogeneous vein wall. The simulated blood velocity conditions are U = 0, 1, 2.5, 5, 10, 20, and 40 mm/s. The lower the blood velocity, the higher the temperature in the vein wall and the greater the tissue damage. The region that is influenced by temperature in the case of the stagnant flow occupies approximately 28.5% of the whole geometry, while the region that is influenced by temperature in the case of continuously moving electrode against the flow direction is about 50%. The generated RF energy induces a temperature rise of the blood in the lumen and leads to an occlusion of the blood vessel. The result of the study demonstrated that higher blood velocity led to smaller thermal region and lower ablation efficiency. Since the peak temperature along the venous wall depends on the blood velocity and pullback velocity, the temperature distribution in the model influences ablation efficiency. The vein wall absorbs more energy in the low pullback velocity than in the high one.

Computer Modeling for Radiofrequency Bipolar Ablation Inside Ducts and Vessels: Relation Between Pullback Speed and Impedance Progress

“…The proposed model can quantify the relationship between pullback speed, applied power, and temperature distributions around the duct or vessel. Although a previous model had already been developed for RF ablation of varicose veins [24], it fell short of our objectives for several reasons: (i) it did not consider the geometry shown in Figure 1, in which the catheter completely occupies the duct lumen, but instead a thin catheter in the center of the vessel with blood flowing around the electrode and (ii) it did not solve the electrical problem, but assumed the electrode surfaces to be the source of heat for keeping the temperature constant at 85°C, and so was not able to compute impedance progress during RF heating.…”

Розробка Моделей Біполярних Електродів Для Ефективного Розподілу Тепла При Радіочастотній Абляції Варикозного Розширення Вен

“…У даний час математичне моделювання процесу РЧА є невід'ємною частиною робіт із удосконалення одного з найпоширеніших методів абляції з використанням біполярних електродів [2][3][4][5][6][7][8][9]. Роботи [2][3][4][5] описують оптимізовані біполярні системи РЧА і нові біполярні радіочастотні абляційні пристрої для лікування варикозного розширення вен із оптимізованою конструкцією електродів. Автори провели чисельне моделювання й експерименти in vitro для оцінювання ефективності та безпеки системи.…”

Simulation, Fabrication and Analysis of Silver Based Ascending Sinusoidal Microchannel (ASMC) for Implant of Varicose Veins

“…After selecting the k-epsilon model, power law is selected from the Create/Edit Materials because of the blood rheological property [ 77 ]. For the boundary conditions and reference values, the material properties of blood are given to the setup section of ANSYS [ 78 ]. The flow rate is determined by the equation: .…”