Elevated plasma fibrinogen level predicts suboptimal response to therapy with both single- and double-bolus eptifibatide during percutaneous coronary intervention.

Abstract

This study sought to determine the factors associated with suboptimal platelet inhibition (PI) with single- and double-bolus eptifibatide during percutaneous coronary intervention (PCI). Although PI > or = 95% measured 10 min after glycoprotein IIb/IIIa inhibitor therapy is associated with improved outcomes following PCI, this level of PI often is not achieved. We prospectively studied 150 patients undergoing PCI with single-bolus eptifibatide (180 microg/kg) (n = 100) and double-bolus eptifibatide (180 microg/kg administered 10 min apart) (n = 50) followed by standard infusion (2 microg/kg/min). Measuring platelet aggregation at baseline and at 10 min and 30 to 45 min after eptifibatide bolus, patients were classified as optimal responders (OPT) (> or =95% PI) or suboptimal responders (sub-OPT) (<95% PI) based on 10-min PI after final bolus. Suboptimal PI was achieved in 61% of patients with single-bolus eptifibatide and in 36% with double-bolus eptifibatide. In the single-bolus group, sub-OPT had higher fibrinogen levels (324 +/- 85 mg/dl vs. 259 +/- 49 mg/dl, p = 0.0002), platelet counts (221 +/- 70 vs. 186 +/- 47, p = 0.008), and white blood cell counts (7.7 +/- 2.3 vs. 6.6 +/- 1.9, p = 0.02). In the double-bolus group, sub-OPT also had higher fibrinogen levels (324 +/- 68 mg/dl vs. 278 +/- 53 mg/dl, p = 0.01) and were more likely to be smokers (38.9% vs. 9.4%, p = 0.01). Multivariable analysis showed that fibrinogen level was the only independent predictor of suboptimal PI, with fibrinogen cutoffs at 375 and 325 mg/dl predicting suboptimal PI (single-bolus: 100% and 90.0%, respectively; double-bolus: 100% and 60%, respectively) with both doses. During PCI, both single- and double-bolus eptifibatide provide suboptimal PI in a substantial proportion of patients. A fibrinogen level >375 mg/dl is a strong predictor of suboptimal PI.