Changes in plasma histamine during orthotopic liver transplantation in the pig

Hypotension and cardiac arrhythmia are commonly seen during liver transplantation both in man and in experimental animals. The cardiovascular changes may be explained by release of vasoactive substances, e.g. histamine, into the systemic circulation. Abdominal operations are followed by an increased histamine concentration in portal blood. If the liver clears excess histamine from the splanchnic system, an increased histamine concentration should not be found in the systemic circulation. We measured plasma histamine in peripheral arterial blood, blood from the right atrium and portal blood in different phase of liver transplantation in ten pigs. Histamine concentration increased in the portal vein in the anhepatic phase (basal 15.85 pmol/ml to 34.67 pmol/ml, median, p less than 0.05) but no changes were found in arterial or right atrium samples. Venous and later arterial revascularisation were not followed by any changes in histamine concentration in arteria and right atrium samples. We conclude that the transplanted liver can eliminate splanchnic histamine and that histamine is unlikely to be involved in the cardiovascular changes which are seen after revascularisation of the liver.