Release of chemoattractants and neutrophil activation in acute myocardial infarction immediately after successful recanalization of the infarct-related vessel by angioplasty

The study investigated inflammatory responses in evolving myocardial infarction. Fifteen patients with acute myocardial infarction, who had undergone balloon recanalization of the infarct-related coronary artery within 4 h after onset of symptoms, were examined. Blood samples were obtained through the guiding catheter and from the pulmonary artery before and immediately after successful recanalization. After recanalization, plasma from the pulmonary artery was 47% (quartiles: 19%, 78%; P=0.001) more chemotactic to neutrophils from normal donors than before recanalization. Furthermore, significant changes in neutrophil function were found in the pulmonary artery. Compared to the values before recanalization, the nitroblue tetrazolium score rose by 31% (quartiles: 4%, 37%; P=0.003), FMLP-stimulated Superoxide anion production by 10% (quartiles: 0%, 39%; P=0.020), and chemotaxis by 46% (quartiles: 0%, 81%; P=0.011), while neutrophil filterability decreased by 28% (quartiles: 15%, 47%; P=0.010). No significant changes in neutrophil parameters were found in the arterial blood. The study indicates that chemoattractants are released in the early reperfusion period of evolving myocardial infarction. These chemoattractants may act as inflammatory mediators causing neutrophil activation.