Chronic vitamin K antagonist therapy and bleeding risk in ST elevation myocardial infarction patients.

Objectives: Acute management of ST elevation myocardial infarction (STEMI) patients on chronic vitamin K antagonist (VKA) therapy is uncertain. This study aims to estimate in-hospital major bleeding risk among STEMI patients on chronic VKA treated with primary percutaneous coronary intervention (PCI); and determine the relationship between bleeding and acute treatments stratified by international normalised ratio (INR) values.

Methods: We retrospectively examined 120,270 STEMI patients treated with primary PCI at 586 national registry hospitals (2007-2012).

Results: Overall, 3101 patients (2.6%) were on VKA which was associated with increased in-hospital major bleeding risk when compared with patients not on VKA (17.0%, vs 10.1%; adjusted OR 1.26, 95% CI 1.13 to 1.40). In patients on VKA, admission INR ≥2.0 was not associated with an increase in bleeding risk compared to INR <2.0. Patients on VKA were more likely to receive clopidogrel or bivalirudin within 24 h of presentation (acute), but less likely to receive prasugrel, heparin, or glycoprotein IIb/IIIa inhibitors (GPI). In those patients, acute GPI was associated with increased bleeding risk (adjusted OR 1.92, 95% CI 1.54 to 2.40) while bivalirudin was associated with decreased risk (adjusted OR 0.69, 95% CI 0.55 to 0.86); bleeding risk associated with heparin, bivalirudin, ADP-receptor blockers, or GPI was similar between INR ≥2.0 and <2.0.

Conclusions: In STEMI patients treated with primary PCI, chronic VKA therapy was associated with a significant increase in in-hospital major bleeding risk compared to no VKA therapy, irrespective of whether admission INR was ≥2.0 or not. In patients on VKA, GPI was associated with increased bleeding risk while bivalirudin was associated with decreased risk.