Etiopathogenesis of hemolytic reactions in total artificial heart recipients.

Hemolysis in total artificial heart (TAH) recipients was analyzed. From a total of 66 long-term experiments lasting from 30-314 days performed in the Brno Research Center, in 53 animals, the total red blood cell (RBC) count, hematocrit, total hemoglobin, and free plasma hemoglobin were investigated. We could essentially divide the whole group of calves in 2 subgroups. The first subgroup was calves with hemolytic reactions, and the second subgroup was calves without any hemolytic reaction at all. In the first subgroup, hemolysis occurred in 47% of the overall number of animals during extracorporeal circulation (ECC), in 15% during ECC and later periodically during the experiment, in 8% during ECC and then continuously during the experiment, and finally in 10% not during ECC but repeatedly during the experiment. In 20% of the animals from the overall number, hemolysis did not occur at all (second subgroup). These results testify to the great individual differences within 1 breed (Bohemian with a substantial component of Holstein). These differences are further modified by exogenous and endogenous factors. First, the inborn resistance of the RBC membrane and also thrombi formation and the mineralization of the driving diaphragm are very important. The extreme situation of decreased RBC membrane resistance was proved using a calf from another breed, the slow growing Scottish Highland breed, which did not survive 22 days of pumping due to intractable lethal hemolysis. These factors are also indicated by the hemolytic action of some drugs (e.g., Dopegyt) used during the experiment for another reason. Also important are the mechanical forces of pumping, surface moieties of the biomaterial, mineralization of the driving diaphragms, thrombi formation, infection, etc. Essentially, the hemolytic reaction in the TAH recipient has a multifactorial character. Hemolysis is undoubtedly an important factor, which can have a profound impact on the length of survival. The experimental and clinical experiences must be continuously integrated, and conclusions valid for human TAH application must be considered as very important for further TAH experimental and clinical research.