Comparison of Safety and Efficacy of Unfractionated Heparin Versus Bivalirudin in Patients Undergoing Percutaneous Coronary Intervention.

Background: Anti-platelet and anti-coagulant adjunctive therapies are associated with a clinically significant increased risk of major bleeding. We retrospectively assessed in-hospital major adverse clinical events (MACE) and major bleeding in patients undergoing percutaneous coronary intervention (PCI) who received either unfractionated heparin (UFH) or bivalirudin.

Method: Consecutive patients undergoing PCI for acute coronary syndrome (ACS) at Fremantle Hospital from August 2008 to December 2013 were identified. Patients received dual antiplatelet therapy (DAPT), with either UFH (50-100IU/kg) or bivalirudin (bolus 0.75mg/kg and infusion 1.75mg/kg/hr). Adjunctive glycoprotein IIb/IIIa (GPIIbIIIa) antagonist use was at the operator's discretion. In-hospital events were identified from case notes and PCI database review.

Results: Of 3371 patients identified, 1740 received UFH and 1631 received bivalirudin. The two groups were similar with respect to age, 62.5 SD 12.1 yrs vs. 62.8 SD 12.2 yrs, (p=0.575) female gender, 24% vs. 26% (p=0.10), current smokers, 66% vs. 70% (p=0.53), diabetes, 25% vs. 26% (p=0.62) and the use of DAPT (p=ns). Presentation with ST-segment-elevation myocardial infarction (STEMI) was significantly higher in the UFH group (28% vs. 19%, p<0.001). The use of transfemoral arterial access was similar (93% UFH vs. 92% bivalirudin) (p=0.41). More patients received GPIIb/IIIa antagonist in the UFH group (30% vs. 3%; p <0.001). There was no difference in pre-discharge acute stent thrombosis (<24hours) occurring in 1.0% with UFH vs. 0.5% with bivalirudin (p=0.20). The equipoise on the outcomes of stent thrombosis persisted after multivariate adjustment for difference in rates of STEMI. In-hospital BARC Type 1-3 major bleeding occurred in 3.7% in the UFH group vs. 2.9% in the bivalirudin group (p=0.20).

Conclusion: Unfractionated heparin compared with bivalirudin was not associated with a higher incidence of in-hospital MACE or major bleeding in a cohort with overall high rates of transfemoral access, despite significantly higher use of GPIIb/IIIa antagonists in the UFH group.