Constructional and Functional Characteristics of Recent Total Artificial Heart Models TNS Brno VII, VIII, and IX

Abstract

Twelve total artificial heart (TAH) models have been developed at the Brno Research Center. Devices VII, VIII, and IX were constructed on the principle of asymmetry. Three main objectives had to be fulfilled by this construction. First, contact of the flap inflow valve with the diaphragm during the pumping cycle had to be avoided. Second, the evacuation regimen of the blood chamber needed to be improved. Third, the danger of thrombi formation due to the lesser incidence of the dead corners had to be decreased or eliminated. The type VII heart has a roof-shaped polyurethane valve in the outflow tract whereas the type VIII heart has a flap valve. The decrease of thrombi incidence around the outflow valve was thus secured, and the driving pressure was decreased as well. In the type IX heart, the small additional flap valve is attached to the outflow valve. In one Brno VII device, Imachi's jellyfish valve has been mounted. Altogether, 62 long-term experiments with survival times of 30-314 days have been performed. To this number, 4 comparative experiments using the Rostock artificial heart were added.

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

“…The total artificial hearts (TAH) used in our experiments were the pumps signed as TNS‐BRNO‐II (23 calves), TNS‐BRNO‐III (1 calf), TNS‐BRNO‐VII/120cc (36 calves), TNS‐BRNO‐VII/80cc (1 goat), TNS‐BRNO‐VIII (1 calf), and ROSTOCK‐TAH (4 calves). TNS‐BRNO‐II was made of polymethylmethacrylate; TNS‐BRNO‐III, VII, VIII, and the most recent, not experimentally verified TNS‐BRNO‐IX were made of Czechoslovak polyurethane; and the ROSTOCK hearts were made of pellethane (3). The control and driving units CHIRASIST TN were originally developed by our experimental group (4,5).…”

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

“…The materials and methods concerning the type of the TAH implanted in our long‐term experiments and the arrangement of the experiments in our 66 animals (65 calves and 1 goat) were published elsewhere (5–10). In this study, dealing with the evaluation of the EM changes of 3 vital organs (liver, kidney, and lungs) in 51 long‐term survivors, we evaluated the EM findings in 22 animals (21 calves and 1 goat) with the antihypertensive treatment (average survival 162 days of pumping, mean ± 59.2 SD; the longest survival 293 days) and in the untreated group.…”

Surface modification of metallic materials designed for a new generation of artificial heart valves

“…The blueprint of the material requires well-known rheological properties of the polymer (thermoplastic polyurethane (TPU)), [8][9][10] simulation methods exceeding the current state-of-the-art, precise positioning of the metal frame and an adapted microinjection moulding cycle to avoid frame collapse due to the high pressure of the melt during cavity filling. [11][12][13][14][15][16] In addition, aspects of heartvalve sealing are challenging, but essential for preventing wear of the TPU leaflet. The deposition of thin flexible coatings (doped diamond like carbon (DLC) 17−19 ) on the TPU and Ti by sputtering techniques may provide lowfriction-based wear resistance and additionally improve the haemocompatibility of the TPU.…”