RATE-PROCESS MODEL FOR ARTERIAL TISSUE THERMAL-DAMAGE - IMPLICATIONS ON VESSEL PHOTOCOAGULATION

A numerical model for thermal damage to human arterial tissue is prese nted, based on protein denaturation kinetics. The model involves deter mination of coefficients of rate processes A and Delta E, which are ti ssue type-dependent (arterial tissue in this study), and definition of threshold damage. A feedback-controlled constant surface temperature device was used to induce 80 coagulative lesions of arterial human tis sue ranging in temperature from 66 degrees C to 76 degrees C and in du ration from 15 to 1,500 seconds. The measured coefficients were determ ined to be A = 5.6 x 10(63) s(-1) and Delta E = 430 KJ mole(-1). These numerical values closely approximate the coefficients of the rate pro cess for denaturation of collagen molecules. These and other histologi cal observations strongly suggest collagen to be the primary coagulati ng component of arterial tissue at the onset of thermal coagulative da mage. The ability of this model to predict onset of tissue coagulation during laser coagulation was studied using 10 postmortem human arteri al samples exposed to argon laser irradiation. (C) 1994 Wiley-Liss, In c.