MYOCARDIAL NEUTROPHIL SEQUESTRATION AND ACTIVATION RELATED TO THE REPERFUSION OF HUMAN HEART DURING CORONARY-ARTERY SURGERY

Objective: The aim was to determine if neutrophils are activated and s equestered as they pass through postischaemic human myocardium. Method s: The occurrence of neutrophil activation during the reperfusion of t he ischaemic myocardium was investigated in 16 selected patients under going coronary artery bypass; surgery. Neutrophils were counted and el astase and lactoferrin released into the plasma were measured simultan eously in myocardial venous blood and in peripheral venous blood, befo re aortic cross clamping (T0), and two (T1), 10 (T2), and 20 (T3) min after unclamping. Results: At T0, no statistically significant differe nce was noted between peripheral and myocardial blood with respect to the three variables studied. Reperfusion was associated with a signifi cantly lower neutrophil count in myocardial blood compared to peripher al blood (p<0.001), suggesting that neutrophils were trapped within th e myocardium during reperfusion. In addition, levels of elastase (T1, T2, and T3), and lactoferrin (T1) were significantly higher in myocard ial blood as compared to peripheral blood (p < 0.001), suggesting that activated neutrophils released their granular content into the plasma milieu. Conclusion: We provide evidence consistent with local neutrop hil activation during myocardial reperfusion in patients undergoing co ronary artery bypass surgery, in addition to the well described system ic activation related to cardiopulmonary bypass.