Platelet activation after stenting with heparin-coated versus noncoated stents

In animal models, heparin coating reduces platelet accumulation induced by coronary stenting. However, reduced platelet activation has never been demonstrated in humans. The purpose of the current study was to investigate the effect of heparin coating on platelet activation after coronary artery stenting.

In a prospective, randomized, pilot study of 50 consecutive elective patients, platelet activation was analyzed by measuring aggregation and surface receptor expression before and at 2 hours, 24 hours, 5 days and 30 days after implantation of either heparin-coated or noncoated stents.

There was less platelet activation after implantation of a heparin-coated stent, as indicated by reduced expression at 24 hours of active glycoprotein (GP) IIb/IIIa (10.3 +/- 6.1 vs 6.7 +/- 2.1, P =.014), and total GP IIb/IIIa (382 +/- 101 vs 306 +/- 88, P =.01). A trend at 30 days poststenting of lower total (383 +/- 150 vs 296 +/- 86, P =.07) and active GP IIb/IIIa expression (10.3 +/- 6.9 vs 7.5 +/- 2.9, P =.15) was also observed with the heparin-coated stent). Aggregation and stimulated p-selectin did not differ between stent types.

Use of a heparin-coated stent in this pilot study of elective patients was associated with primarily less early platelet expression of GP IIb/IIIa. These findings have implications on the risk of subacute thrombosis and deserve further investigation.