Leukocyte activation with platelet adhesion after coronary angioplasty: mechanism for recurrent disease?

Objectives. The purpose of this pilot study was to determine whether leukocyte activation occurs, whether leukocyte-platelet complexes develop and whether there is any association between these findings and clinical outcome after coronary angioplasty. Background. Increased expression of CD11b on monocytes and neutrophils promotes their adhesion to endothelial cells, extracellular matrix and smooth muscle cells. Thrombin-activated platelets adhere to monocytes and neutrophils through P-selectin. These cell complexes may affect the inflammatory process and, thus, the outcome of coronary angioplasty. Methods. During elective single-vessel coronary angioplasty in 11 men, samples were obtained for flow cytometric detection of CD11b, as well as the percent of leukocytes with adherent platelets and the intensity of bound platelet fluorescence (number of platelets/leukocyte). Results. After angioplasty, there was an increase in CD11b (monocytes: p = 0.001, neutrophils: p = 0.02) and leukocytes with adherent platelets (p = 0.02). During follow-up, five patients remained in stable condition and six had subsequent clinical events: restenosis and progression of disease requiring coronary artery bypass grafting (n = 3), myocardial infarction involving the dilated artery (n = 1) and unstable angin (n = 2). Values for leukocyte CD11b expression, the percent of leukocytes with adherent platelets and the intensity of bound platelet fluorescence were higher both before and after angioplasty in the six patients experiencing clinical events. Conclusions. Despite standard aspirin and heparin therapy, leukocyte activation with platelet adherence occurs after coronary angioplasty. The magnitude of leukocyte activation and platelet adherence appears to be higher in patients experiencing late clinical events.