FUNCTION OF ADULT-PIG HEARTS AFTER 2 AND 12 HOURS OF COLD CARDIOPLEGIC PRESERVATION

Background. Most cardioplegic solutions have been developed using the classic Langendorf heart perfusion model, which only allows a short ex perimental followup. Our aim was to investigate hearts after prolonged storage by using a physiologic model including prolonged perfusion wi th normal, fresh blood. Methods. Sixteen hearts from 60-kg pigs were p reserved with dextran-enriched (dextran-40, 35 g/L) St. Thomas' soluti on for 2 or 12 hours after which they were continuously reperfused for 12 hours with normal blood, supplied by a support pig. A flexible bal loon, fixed to an artificial valve apparatus connected to a circuit sy stem, was inserted in the left ventricle for obtaining measurements of hemodynamic performance. Results. During the first 3 to 4 hours of re perfusion there was no significant difference in left ventricular deve loped pressure, cardiac output, minute work output, or oxygen consumpt ion between the two groups. After this time left ventricular developed pressure (p < 0.001), cardiac output (p < 0.01), minute work output ( p < 0.01), and oxygen consumption were significantly lower in the 12-h our group. Coronary flow was higher (p < 0.01) and coronary vascular r esistance lower (p < 0.01) during the first 5 to 6 hours of reperfusio n in the 12-hour group. After 12 hours of reperfusion coronary vascula r resistance was significantly higher (p < 0.01) in the 12-hour group. Conclusions. High-degree and long-lasting coronary hyperemia at the b eginning of reperfusion can be a sign of unsatisfactory preservation o f the heart. This investigation shows the importance of reperfusion wi th normal blood and a long follow-up period after postischemic reperfu sion when studying the effect of cardioplegic solutions. (Ann Thorac S urg 1998;66:73-8) (C) 1998 by The Society of Thoracic Surgeons.