Morphological properties of carrying capacity of coronary bed microvessels during surgical treatment of congenital heart under cardiopulmonary bypass disease in infants

An intraoperative analysis of the changes in morphological properties of myocardium microvessel carrying capacity in infants under 3 years old suffering from congenital heart disease was carried out by using an electron microscope, with extracorporeal circulation applied under moderate hypothermia (33-34 °С) and with the myocardium protected by means of Kustodiol cardioplegic solution. A positive antiaggregatory effect of Kustodiol solution during surgical treatment of the congenital disease in babies (under 1 year old) was obtained at the structural level of a metabolic link of the coronary bed. A differential approach to studying the mechanisms of coronary microvessels closure revealed some objective signs, which distinguish intraoperative reorganization of an immature myocardium of babies under 1 year old from that of patients over 12 months of age. These signs include a more expressed edema of coronary microvessels endothelium with concomitant fragmentation of edematous endothelial cells and a low degree of functional opening of the collapsed capillaries at a reperfusion stage of the operation. Using the ultrastructural criteria made it possible to find out that the efficacy of cardiac protection in the context of preservation of the structure and function of coronary microcirculation, when applying Kustodiol solution to protect the myocardium, was higher in patients over 12 months old as compared to that in babies under 1 year old.