S. Doležel, J Vašků, Jaroslav Filkuka, Eva šotáková, Dostál M, Jan Vašků, Guba P, Bohumil Bednarřík, P. Urbánek, B. Hartmannová, Viktor Pavlíček, Vladimír Krčma, Urbánek E, Karel Cídl, Pavel Hanzelka, Helena Janečková, O Šotolová, Tomá šSládek, Lubomír Krček, and Cerný J
A 150-day experiment in a calf with an implanted total artificial heart, TNS-BRNO-II, is described. The Czechoslovak TAH-BRNO-II device is a hybrid; the outer housing is made of polymethylmethacrylate, the moving parts of segmented polyurethane. The blood flow through the device after the surgery gradually increased from 7 L/min to 12 L/min by the end of the experiment. Atrial pressures were automatically maintained at the same level, about one kPa on both sides. The left systolic time was automatically derived from the pump emptying phase; the right systolic time was maintained between 40% and 50%. After the surgery, normal values of blood gases, stabilization of respiratory activity, and normalization of gastrointestinal functions were reached very soon. Anticoagulant therapy was performed during the whole experiment, with several periods of increased bleeding tendency. The clinical state of the calf was essentially physiological until the 94th day of the experiment, when acute bronchopneumonia, with a high fever, over 41°C, initiated a series of complications (pseudomembranous enterocolitis, followed by sepsis lenta). The fatal complication was sudden impairment of the coagulation mechanisms on the 149th to 150th day of the experiment. This was the basic reason for the subsequent death of the animal, caused by acute cerebral anemic anoxia, which could not be prevented by immediate therapeutic procedures. In spite of these complications, the clinical state of this calf was relatively good until the end of the experiment. Autopsy revealed minimal thromboembolization at the valves. The outer surface of the diaphragm was covered with pseudoneointimal deposits and the inlet orifices were free of pannus or other connective tissue crescents. Macroscopic signs of infection were not seen, but bacteriological cultivation from internal organs confirmed Klebsiella infection. The state of the device at the time of autopsy, with simultaneous undisturbed function of the control and driving unit, showed the possibility of still longer survival.