Electronmicroscopic changes in selected vital organs after long-term totalartificial heart pumping in animal experiments

Electronmicroscopic (EM) evaluation of selected vital organs (liver, kidney , lung) informs us about otherwise hardly detectable changes during total a rtificial heart (TAH) pumping. In our experiments, we compared 2 groups of long-surviving animals in which the TAH TNS-BRNO pneumatic device was impla nted (TNS-BRNO-II and VII in 45 experiments, TNS-BRNO-III in 1 experiment, and TNS-BRNO-VIII in 1 experiment). In 4 experiments, the Restock TAH (NABE L, TAH Research Center, Restock, Germany) was implanted. One group of 22 an imals with an average survival of 162 days (the longest, 293 days) was subm itted to an antihypertensive treatment; another 1 of 29 calves with an aver age survival of 98 days (the longest, 173 days) was untreated. The evaluati on was performed using a scale (0 to 3) based on very precisely fixed crite ria. EM pathologic changes documented various stages of ischemic damage. Ex cept for the liver, no significant difference was found between both groups , despite the substantially prolonged survival in the treated group. Very i mportant was the general state of mitochondria, endoplasmic reticulum, and nucleus. Further, the state of glomerular podocytes in the kidney and the s tate of interalveolar septa and of pneumocytes constituting the air-blood b arrier for gas exchange in the lungs are especially important. In some anim als of both groups, the EM findings were completely normal, especially in t he lung.