Variations of blood PAF-acether levels during coronary artery surgery

Abstract

Extracorporeal circulation (ECC) is associated with thrombocytopenia and transient leukopenia. After ECC and coronary artery bypass graft (CABG) surgery, some patients can develop pulmonary and cardiac dysfunction, which might be related to the release of various mediators such as thromboxane A 2, C 5a, and C 3a anaphylatoxins. The involvement of PAF-acether (PAF), a potent vasoactive thrombocytopenic and leukoneutropenic agent, has not been determined. Therefore, 10 patients were studied during and after CABG. The release of PAF, lipo PAF (PAF bound to blood lipoproteins), and lypo PAF (PAF precursor and metabolite) was measured in blood from the left atrium, radial artery, and pulmonary artery before and after CABG. PAF, lipo PAF, and lyso PAF were also determined during ECC at the entry and exit points of the oxygenator. Hemodynamic parameters, platelet, and leukocyte counts in the pulmonary artery were measured simultaneously. PAF did not increase significantly during ECC; it showed a transitory six-fold increase immediately after CABG in the radial artery (0.18 ± 0.13 v 1.09 ±0.36 ng/ mL, P < 0.05), but not in the pulmonary artery (0.10 ± 0.03 v 0.56 ± 0.21 ng/mL, P > 0.05). Blood PAF amounts in the radial artery were significantly higher than in the left atrium following ECC (1.09 ± 0.36 v 0.06 ± 0.04, P < 0.05), probably indicating PAF production in the heart. No variation of blood lipo PAF and lyso PAF was observed. No correlation was seen between PAF amounts and blood cell count. The positive correlation observed between PAF levels in the left atrium and the pulmonary arterial pressure (r = 0.80, P < 0.001) strengthens the putative physiologic role of this agent in pulmonary artery hypertension. The clinical use of PAF antagonists may help to determine PAF involvement in human physiology and pathology.