CHANGES IN ADHESION MOLECULE EXPRESSION AND OXIDATIVE BURST ACTIVITY OF GRANULOCYTES AND MONOCYTES DURING OPEN-HEART-SURGERY WITH CARDIOPULMONARY BYPASS COMPARED WITH ABDOMINAL-SURGERY

Cardiac and major abdominal surgery are associated with granulocytosis in peripheral blood. The purpose of the present study was to describe the granulocyte and monocyte oxidative burst and the expression of ad hesion molecules following cardiac surgery with cardiopulmonary bypass and abdominal surgery. The ability to respond with an oxidative burst was measured by means of flow cytometry using 123-dihydrorhodamine. T he adhesion molecules CD11a/CD18, CD11c/CD18, CD44 were measured using monoclonal antibodies. Blood samples from eight patients undergoing o pen-heart surgery were taken before surgery, 1, 5, 10 and 20 min after aortic clamping, and then 1, 5, 10 and 20 min and 1, 2 and 3 h after declamping. Samples from eight patients undergoing abdominal surgery w ere taken before surgery, at the end of surgery, and 2 and 3 h post-op eratively. A decrease in number of granulocytes and monocytes during c ardiopulmonary bypass was observed. The percentage of CD11a-positive g ranulocytes increased from 30% preoperatively to 75% following cardiop ulmonary bypass, while CD44-positive granulocytes increased from 5% to 13%. Despite the extent of the changes, these were not significant. T he oxidative burst of the granulocytes and monocytes decreased after d eclamping to 15% and 27% of initial values in vitro. Several hours aft er surgery, there was no significant difference between the two groups . These results can be explained by a granulocyte and monocyte refract ory response developing subsequent to an increased per-operative oxida tive burst activity, and the induction of adhesion molecules on granul ocytes associated with the cardiopulmonary bypass and surgery. In conc lusion, open-heart surgery with cardiopulmonary bypass was associated with a rapid and pronounced activation of leukocytes which may play a role in reperfusion injury.