Abstract
OBJECTIVES: The purpose of this study was to describe temporal trends and determine the comparative effectiveness of bivalirudin versus unfractionated heparin (UFH) during percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI).
BACKGROUND: Several clinical trials have compared the safety and effectiveness of bivalirudin versus UFH during PCI for STEMI, but results have been conflicting.
METHODS: Trends in anticoagulant use were examined among 513,775 PCIs for STEMI from July 2009 through December 2014 within the National Cardiovascular Data Registry CathPCI Registry. We conducted an instrumental variable analysis comparing bivalirudin with UFH, using operator preference for bivalirudin as the instrument. We used a test of mediation to determine the extent to which differences in outcomes between anticoagulants were due to differences in use of glycoprotein IIb/IIIa inhibitors (GPI). Primary outcomes were in-hospital bleeding and mortality.
RESULTS: Bivalirudin use increased from 2009 through 2013, followed by a new decline. GPIs were used in 74.7% of UFH PCIs versus 26.5% of bivalirudin PCIs. In unadjusted analyses, bivalirudin was associated with decreased bleeding (risk difference [RD]: -4.2%; p < 0.001) and mortality (RD: -0.84%; p < 0.001). After instrumental variable analyses, bivalirudin remained associated with less bleeding (RD: -3.75%; p < 0.001), but not mortality (RD: -0.10%; p = 0.280). The higher rate of GPI use with UFH was responsible for more than one-half of bivalrudin's bleeding reduction (GPI-adjusted RD: -1.57%; p < 0.001). Bleeding reductions were negligible for transradial PCI (RD: -0.11%; p = 0.842).
CONCLUSIONS: The use of bivalirudin during STEMI has decreased. Bivalirudin was associated with reduced bleeding and no mortality difference. The bleeding reduction with bivalirudin was largely explained by the greater use of GPIs with UFH.