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Biomedical subjects

R Kiraly

Publications and source records attributed to R Kiraly.

At least 37 records · Page 2Linked to original sources
PubMed1977

145 days survival of calf with total artificial heart (TAH).

A calf with a biolized TAH was maintained in reasonably good physiological condition for a major portion of a 145-day experiment as indicated by near normal growth rate and laboratory data. The mechanism for the high CVP and CBV at the beginning and end of the experiment were correlated with protein metabolism. No evidence of thromboembolism was found at autopsy and only modest congestion with minimal parenchymal damage was observed. The cardiac prosthesis itself was free of thrombus, although slight calcification was found on the valves and diaphragms. The pump performance, however, remained satisfactory. In addition, endothelialization appeared to be starting on a portion on the inside of the pump.

Animals↗
PubMed1977

Survival for 145 days with a total artificial heart.

A calf into which a biolized, total artificial heart (TAH) had been implanted survived for 145 days. All measured physiological parameters except central venous pressure (CVP) were back to normal one month after implantation, and thereafter the animal's physiological development was similar to that of a normal calf. The intimal weight, which was 96 kilograms at implantation, reached 190 kilogram at the end of experiment, with a daily gain rate of 0.9 kilogram per day. After the nineteenth postoperative week, signs of congestive heart failure appeared, such as high venous pressure, ascites, and enlarged liver although the calf outwardly appeared well. On postoperative day 146, the animal started foaming at the mouth, and a convulsion occurred; then, the experiment was terminated after 3,494 hours of pumping. At autopsy, there were acute bilateral bronchopneumonia involving mostly both upper lobes, pulmonary edema, slight chronic pneumonitis, and hepatomegaly. There were no serious thrombotic deposits inside the cardiac prosthesis.

Animals↗
PubMed1976

Application of aldehyde treatments to cardiovascular devices.

Biolized natural and synthetic materials represent a new class of materials. Aldehyde treatment of natural tissue creates cross-links in the collagen molecules while retaining mechanical strength and collagen structure. Synthetic polymers can also be biolized by the addition of protein and aldehyde treatment. Cross-linked materials such as these are resistant to degradation by proteolytic enzymes. The procedure for the aldehyde treatment of natural tissue and protein polymer composites has been established, and in vivo and in vitro studies have demonstrated an improved blood compatibility. Long-term survival with TAH and LVAD implanted animals has shown the successful application of these materials without the use of anticoagulants. Pseudoneointima growth occurs on these surfaces, and results to date indicate growth stabilization within 2 wks of impalntation. Studies are currently underway to fully characterize the pseudoneointima formed on the biolized surfaces of cardiac prostheses.

Aldehydes↗
PubMedDate not supplied

In vitro and in vivo performance evaluation of a totally implantable electrohydraulic left ventricular assist system.

The biolized electrohydraulic left ventricle assist devices were tested in 14 calves with an average survival time of 162 days and as long as 250 days without the use of anticoagulants. In vitro, the system pumped 4.1 L/min at a low 4.8 mmHg fill pressure with a mean afterload of 100 mmHg and rate of 46 bpm. A flow rate of 13.5 L/min was observed at 155 bpm and 110 mmHg afterload. Motor frequency and current increased with increasing flow rate (162 Hz, 0.67 amp at 2.5 L/min; 484 Hz, 2.43 amp at 13.5 L/min). Flow rate did not change significantly with afterload pressure. The complete system was implanted in a 100 kg calf. Synchronization of the blood pump with the natural heart was demonstrated at heart rates of 85 to 167 bpm. The synchronized flow rate varied from 6 to 10.5 L/min despite the considerable heart rate changes and stroke variations. The system hemodynamic performances were acceptable and met NIH requirements.

Animals↗