Electron Microscopic Study of Driving Diaphragms in Long‐Term Survival with a Total Artificial Heart

Abstract

A driving diaphragm in the long-term working total artificial heart (TAH) is under serious mechanical stress, and the long steady contact with blood causes changes to the diaphragm's surface. These changes can be influenced either by local or systemic interventions. In our study, we tried to follow the development of changes to the diaphragm's surface comparing the samples of diaphragms of long (over 30 days) and short (under 30 days) surviving calves and the effect of some preventive measures as well. We could confirm the presence of two types of calcification: a dystrophic calcification affecting primarily formed thrombi and necrotic tissue, and a primary type of calcification that begins in the form of calcifying nuclei on the protein layer of the polyurethane surface that is later on extensively covered with a fibrin network and blood cells. The calcified deposits caused mechanical damage or were the source of microembolization to the vital organs. A clotting mechanism occurs at the same time as the calcifying process from the beginning, often forming a fibrin network in and over the calcified deposits. An attempt at prevention was made by systemic administration of colloidal iron solution, Ferrum Lek (ferri saccharate in a stable colloidal form), based on the concept of the so-called reversed calciphylaxis.

Electronmicroscopic Changes in Selected Vital Organs After Long‐Term Total Artificial Heart Pumping in Animal Experiments

“…The pathogenesis of the CVP increase in the TAH animals has been published elsewhere, and based on this pathogenetic background, we also could perform an essentially successful pathophysiological treatment (5,7,(10)(11)(12). Due to this treatment and also partly due to the systemic antimineralization treatment aimed at the prevention of mineralization of driving diaphragms, we could substantially increase the length of survival (1,2). The ultramicroscopic comparison of the liver in both groups (treated and untreated) shows differences which can be attributed to the positive effect of therapy on the liver tissue.…”

“…Nevertheless, during such a long time, periods can be encountered when the vital organs are affected by various pathological situations caused by the inadequate driving and control regimen of the TAH pumping, by the administration of various drugs, and by adverse body reaction to the material and kinetics of the mechanical system, such as thrombi formation, mineralization of the driving diaphragm, and the increase of the arterial and the central venous pressure (CVP). Except for the measures aimed at preventing calcification (1,2), in 1 group the antihypertensive treatment for securing a longer survival was used. Intercurrent infections with the administration of antibiotics, blood coagulation disorders with either bleeding or thrombi formation, further hemolysis (3) can induce some organ changes, sometimes even in the central nervous system (4),which can be compatible with a longer survival.…”

Total Artificial Heart: The Adaptation and Pathophysiological Deviations in the Recipient

“…In cases where the driving diaphragm was primarily very rapidly covered with thrombi, followed by dystrophic calcification, this method was less effective. However, in treated animals where the diaphragms were endangered by the primary calcification, prevention by the iron treatment was remarkable (2,12,13).…”

Czech Marathon in the Research of Heart Assist Systems and Total Artificial Heart

“…We have carefully studied hemolysis as a multifactorial state; attention was paid to the endogenous and exogenous factors, and the role of the red blood cell membrane resistance to the pumping regimen (16). Very intensive study focused also on the etiopathogenesis of the diaphragm mineralization; very good results in prevention of this state were reached by the reversed calciphylaxis procedure called "anacalciphylaxis" (17,18).…”