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DOI: 10.1055/s-0028-1096255
Regional Myocardial Flow and Metabolism in Canine Heart Transplants after Preservation for 24 Hours[*]
Publication History
Publication Date:
11 December 2008 (online)
Summary
Canine hearts were preserved for 24 hours at 5 °C by intermittent low pressure perfusion (20 cm H2O), using an oxygenated extracellular solution. Coronary flow distribution was estimated by the radioactive microsphere technique during preservation, after orthotopic transplantation, and during resuscitation in isolated heart preparations. Tissue specimens were obtained after 24 hours of preservation to determine regional differences in tissue water content and in tissue levels of creatine phosphate, adenosine triphosphate, and lactate.
The regional distribution of perfusate flow showed systematic changes in the course of preservation. There was a shift in relative regional perfusion from the left ventricle to the right ventricular free wall. The left ventricular subendocardial/subepicardial perfusion ratio decreased progressively (1.26:1 to 1:1.55), while the right ventricular inner/outer ratio remained unchanged (1.25:1) throughout the preservation period. Maximum restriction of flow occurred in the left ventricular papillary muscle. The redistribution of flow was accompanied by corresponding changes in regional myocardial metabolism only if perfusate lactate levels were high. The preservationinduced edema was most substantial in the left ventricular subendocardium. The left ventricular transmural flow gradient was reversed after a 40-minute period of resuscitation in isolated heart preparations. Left ventricular subendocardial muscle was underperfused relative to the subepicardium after orthotopic transplantation (inner/outer ratio 1:1.18).
Key-Words:
Heart preservation for transplantation - Regional myocardial flow - Labelled microspheres - Regional myocardial metabolism - Regional myocardial edema