Effects of platelet glycoprotein IIb IIIa inhibition with abciximab on thrombin generation and activity during percutaneous coronary intervention

Background Antagonists of the platelet glycoprotein IIb/IIIa decrease acute ischemic complications after percutaneous coronary interventions (PCI). Ab ciximab (c7E3 Fab, ReoPro) has been reported to decrease thrombin generatio n in vitro. We investigated in vivo the effect of abciximab therapy on thro mbin generation, thrombin activity, and the activated clotting time (ACT) d uring PCI. Methods We studied 32 consecutive patients who underwent PCI for unstable c oronary syndromes. Group I (n = 11) was treated with heparin plus aspirin, and group II (n = 21) was treated with heparin plus aspirin plus standard-d ose abciximab, administered 5 minutes after the initial heparin bolus. Pati ents received a standardized heparin bolus at time 0, and arterial blood sp ecimens for prothrombin fragment F1.2, fibrinopeptide A (FPA), and ACT were obtained from the guiding catheter at 5 minutes, 10 minutes (ACT only), 20 minutes, and at the end of the PCI. Standard-dose abciximab was administer ed in group II only. Each patient served as his or her own control, and the changes against the baseline were compared between the 2 groups. Results There were no significant differences between the 2 groups regardin g baseline characteristics, hematocrit, and platelet count. Group I patient s had higher ACT and lower F1.2 and FPA compared with group II at baseline. Subsequent measurements demonstrated a gradual decrease in FPA and F1.2 in group II; the end of procedure versus baseline changes that occurred in F1 .2 were significantly different compared with group I (decrease of 0.59 +/- 0.22 nmol/L in group II vs increase of 0.22 +/- 0.3 nmol/L in group I, P = .04), and a trend in the same direction was evident for FPA changes (decre ase of 1.46 +/- 1.16 ng/ml in group II vs increase of 2.25 +/- 1.58 ng/ml i n group I, P = .07). The ACT response to abciximab was variable, but a 6.3% increase (+20 sec) in ACT was documented 5 minutes after abciximab bolus i n group II compared with the 3.4% decrease (-10 sec) observed in group I at the same time point (P = .1). Conclusion Addition of abciximab to heparin plus aspirin during PCI was ass ociated with a significant decrease in thrombin generation and a borderline decrease in thrombin activity.