Expression of inflammation in myocardial tissue of rabbits: Comparison of two miniaturized heart-lung machines

The majority of cases involving the surgical treatment of congenital heart disease require implementation of cardiopulmonary bypass (CPB). However, neonates and infants are particularly prone to serious complications associated with CPB as a result of capillary leak due to cardiovascular failure. These complications are related to the transfusion of foreign blood, the disproportionately large area of contact between the patient's blood and foreign material, as well as the systemic inflammatory response induced by hemolysis. To attenuate these risks, we developed a novel, highly integrative, miniaturized heart-lung machine (MiniHLM) with a static priming volume of only 102mL. This prototype was tested in comparison with a conventional heart-lung machine (static priming volume 213mL) using a rabbit animal model. The animals were anesthetized, sternotomized, and connected to CBP via the aorta and right atrium. The aorta was cross-clamped for 1h. Blood samples for examination were taken at regular intervals. Biopsies of the right atrial appendage (RAA) were removed directly after initiation and after cessation of CPB. After gradual reduction of perfusion with the HLM, all rabbits were successfully weaned from CPB, and the sternum was closed. Foreign blood was not administered in all cases. After cryopreservation of the RAA tissue, de novo transcription of inflammatory cytokines was measured by means of real-time polymerase chain reaction using the comparative C_T method. No significant differences in the expression of the inflammatory parameters of the myocardial tissue samples were found between the study groups.