Intracoronary complement activation does not occur with uncomplicated percutaneous transluminal coronary angioplasty

Background: Activation of the complement system results in a wide range of pathophysiologic effects that can lead to reduced coronary blood flow, myocardial ischemia, and contractile dysfunction. With splitting of the atherosclerotic plaque and exposure of the interior of the plaque during percutaneous transluminal coronary angioplasty (PTCA), components of the complement system are exposed to cholesterol and atheroma lipids, which are known activators of the complement system. Methods: We assessed whether intracoronary complement activation occurs during PTCA by measuring C3a and C5a concentrations, leukocyte counts, as well as the difference in these values, across the coronary circulation. Results: A low level of complement activation was documented prior to PTCA by the finding of elevated C3a levels at baseline, but no further complement activation was demonstrated during or after uncomplicated PTCA. Conclusions: Complement activation does not occur during uncomplicated PTCA in patients treated with aspirin and heparin. These results give some assurance that uncomplicated PTCA does not produce the deleterious effects on coronary blood flow and myocardial function that can be associated with complement activation.