Introduction: Stent implantation has been shown to be superior to balloon angioplasty in patients with acute myocardial infarction (AMI). Newer trials indicate that platelet-leukocyte aggregates are a more sensitive marker for platelet activation than platelet surface marker. Our study examined platelet activation and platelet-leukocyte interaction in blood in patients with AMI randomized to heparin-coated stent implantation versus balloon angioplasty.
Materials and methods: Forty-seven patients with AMI were included into our study. Patients were randomized to heparin-coated stent implantation (n=31) or balloon angioplasty (n=16). Platelet activation, total platelet-leukocyte aggregates and aggregate composition in blood were assessed by flow cytometry before, immediately after and 24 h after intervention.
Results: No differences in platelet activation, total platelet-leukocyte aggregates and aggregate composition were found between both groups before intervention. Immediately after intervention, platelet activation was comparably increased in both groups. Patients treated with heparin-coated stent showed a decrease in total platelet-leukocyte aggregates 24 h after intervention (3.9% [2.8; 4.7] versus 3.2% [2.4; 4.1]; p<0.01). Platelet-monocyte conjugates decreased 24 h after heparin-coated stent implantation compared to balloon angioplasty alone (0.28% [0.17; 0.42] versus 0.49% [0.45; 0.79]; p<0.05). No difference in total platelet-leukocyte aggregates was found in patients treated with balloon angioplasty alone.
Conclusions: An inhibitory effect of heparin-coated stent implantation on total platelet-leukocyte aggregates and platelet-monocyte conjugates in blood was demonstrated in patients with AMI. This reflects heparin-coated stent implantation to be less thrombogenic than balloon angioplasty alone.