A comparative study of a group of eight calves, surviving longer than 1 month with the total artificial heart.

Over the last 2 1/2 years, eight calves with implanted total artificial hearts (from experimental group IV) have survived for greater than 1 month. In this group two subgroups were further differentiated, subgroup IVa, including three calves surviving 31, 35, and 75 days, and subgroup IVb, with five calves surviving 104, 142, 150, and 155 days and one calf still surviving greater than 160 days. Mean survival in the fourth group was greater than 106.5 days. The artificial ventricles used were the TNS-BRNO-II made of polymethylmethacrylate (seven calves) and the TNS-BRNO-III, made of segmented polyetherurethane (one calf). The controller and driving units were of our own design. The Chirasist-TN-3 and TN-4 worked without trouble over the total duration of the studies in all calves. Autoregulation of suction was used in three of these calves. All calves survived in good physiological condition; however, some common changes were observed in all of them, such as a gradual central venous pressure increase and liver enlargement. Anticoagulation therapy was used in all calves. Causes of death were technical in three cases and biological in four. Body weight gains were normal in the majority of these calves, with slight individual differences observed. Diaphragm mineralization of various degrees was observed in three cases. In one of them it was directly related to the cause of death. These results are very encouraging for further development of the total artificial heart research in our center.