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Histopathological analysis can provide important information in long-term experiments with total artificial heart (TAH). Recently, a new type of blood pump, the helical flow total artificial heart (HF-TAH) was developed. This study aimed to investigate the changes in selected vital organs in animal experiments with implanted HF-TAH. Samples from lung, liver, and kidneys from two female goats (No. 1301 and No. 1304) with implanted HF-TAH were analyzed. Tissue samples were fixed in 10% formaldehyde and 4 µm thick transverse sections were stained with hematoxylin-eosin (HE). Additional staining was done for detection of connective tissue (Masson-Goldner stain) and for detection of iron (hemosiderin) deposits (Perls stain). Sections were scanned at 100× and 500× magnification with a light microscope. Experiment no. 1301 survived 100 days (cause of termination was heavy damage of the right pump); experimental goat no.1304 survived 68 days and was sacrificed due to severe right hydrodynamic bearing malfunction. Histopathological analysis of liver samples proved signs of chronic venostasis with limited focal necrotic zones. Dilated tubules, proteinaceous material in tubular lumen, and hemosiderin deposits were detected in kidney samples. Contamination of the organs by embolized micro-particles was suspected at the autopsy after discovery of visible damage (scratches) of the pump impeller surface (made from titanium alloy) in both experiments. Sporadic deposits of foreign micro-particles (presumably titanium) were observed in most of the analyzed parenchymal organs. However, the described deposits were not in direct connection with inflammatory reactions in the analyzed tissues. Histopathological analysis showed the presence of minimal contamination of the lung, kidney, and liver tissue samples by foreign material (titanium very likely). The analysis showed only limited pathological changes, especially in liver and kidneys, which might be attributed to the influence of artificial perfusion often observed in chronic TAH experiments.

Sixty-six long-term experiments were performed on animals (65 calves, 1 goat) after implantation with a total artificial heart (TAH). Animal survival ranged from 30 to 314 days using TAH devices ranging from the TNS-BRNO-II to the TNS-BRNO-VIIII. In these experiments some basic problems were studied which need to be overcome to achieve the optimal physiological status of the animal, the optimal maintenance of the internal environment, and the long-term survival of TAH recipients. The problem areas studied were: the vasomotor regulation of the periphery, the prevention of calcification of the driving diaphragms, the optimal regulation of homeostasis, and the pathogenesis and prevention of infection. The basic precondition for the experiments was the problem-free implantation of a TAH and the subsequent optimal method of postoperative care was investigated. By the gradual multifactorial solution of these individual problems, the prolongation of the survival period of experimental animals was achieved. The definite solution and elucidation of some complications during long-term survival is still an open problem because the multifactorial events that influence long-term TAH survival are often very complicated and can sometimes only be solved by overcoming numerous obstacles as a result of the deep functional interrelationships of the disorders present.