The goal of the work is to find out the changes in the heat parameters of blood plasma denaturation of a son and a granddaughter, in comparison with the same parameters of a 91 years old grandfather with atherosclerosis. The significant changes in heat (Q(d)) and denaturation temperature (T(d)) of albumin, globulins and fibrinogen of 91-year-old patient suffering from atherosclerosis relative to the norm (88-year-old man) are found out. In particular, Q(d) increase by 60% of albumin fat fraction and fibrinogen of F domain and the increase of their T(d) by 2.4 degrees C and 2.8 degrees C relative to the norm; Q(d) decrease by 1.8 times and T(d) increase by 2.9 degrees C of gamma globulin relative to the norm; Q(d) decrease by 6 time of D domain fibrinogen and and globulins by 1.4 and 2.9 times relative to the norm. Total denaturation heat of donor blood plasma is equal to 25.5+/-3 J/g and patient suffering from atherosclerosis is equal to 22.0 J/g. The most significant changes of heat parameters are observed between grandfather and granddaughter: an increase of D domain T(d) by 4 degrees C and Q(d) by 6 times; T(d) increase of albumin fat fraction by 4.3 degrees C and its Q(d) decrease by 10% of granddaughter in comparison with her grandfather. As value Qd of proteins is directly proportional to protein concentration in solutions, we conclude that the significant changes of concentration main proteins in blood plasma and changes of their thermodynamic stability occur at atherosclerosis, relative to the norm.