Silica-free silicone rubber in isolated heart perfusion with blood at 13 °C

Abstract

Isolated lamb hearts were perfused at 13 °C for 24 hr with whole fresh blood using a silicone rubber circuit and a membrane lung ( N = 7); there was formation of thrombi, deposition of fibrin, and an increase in resistance to blood flow in the membrane lung. The perfused hearts fibrillated at hypothermia and showed unequal recovery of function upon final rewarming. There was less rise in membrane lung resistance when the perfusion circuit was primed with blood at 38 instead of 13 °C and then cooled progressively to 13 °C. Some hearts perfused in these circuits were well preserved but others became edematous with loss of ventricular contractility ( N = 6). Coating the perfusion circuit with a hypothrombogenic material, silica-free silicone rubber and priming the circuit at 38 °C prevented any rise in membrane lung resistance during blood perfusion. All the hearts perfused in these circuits ( N = 6) had the same left ventricular function before and after cold perfusion. Thus isolated hearts can be perfused in vitro with whole blood at hypothermic temperature without loss in function when attention is paid to thrombogenicity of materials used to construct the perfusion circuit.