Randomized comparison of platelet-leukocyte aggregates and platelet activation in blood: heparin-coated coiled wire stent implantation versus balloon angioplasty in acute myocardial infarction.

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.