Chronic Vitamin K Antagonist Use Ups In-Hospital Bleeding Among Primary PCI Patients

In patients with ST-segment elevation myocardial infarction (STEMI) who undergo primary percutaneous coronary intervention (PCI), chronic therapy with a vitamin K antagonist is associated with more in-hospital major bleeding, reports a US-based registry study published online October 21, 2014, ahead of print in Heart.

The elevated risk exists regardless of whether patients have a subtherapeutic international normalized ratio (INR) at baseline. However, antithrombotic therapy was found to play a role since the risk was lower with bivalirudin and higher with early glycoprotein IIb/IIIa inhibitor (GPI) use.

Methods
Wassef Karrowni, MD, of UnityPoint Clinic-St. Luke’s Hospital (Cedar Rapids, IA), and colleagues retrospectively studied 120,270 STEMI patients who underwent primary PCI and were enrolled in the Acute Coronary Treatment and Intervention Outcomes Network RegistryGet With The Guidelines (ACTION RegistryGWTG), which is part of the American College of Cardiology’s National Cardiovascular Data Registry (NCDR). Patients were treated at 596 participating hospitals between 2007 and 2012.

In-hospital major bleeding was defined as an absolute decrease in hemoglobin 4 g/dL, an intracranial hemorrhage, a retroperitoneal hemorrhage, or use of red blood cell transfusion in patients with baseline hemoglobin ≥ 9.0 g/dL or in those with baseline hemoglobin < 9.0 g/dL and a witnessed bleeding event.

 


The 3,101 patients (2.6%) who were taking vitamin K antagonists daily at home tended to be older, to present with heart failure or shock, and to have higher prevalence of CAD and other risk factors such as diabetes, hypertension, and dyslipidemia. The group also had more comorbidities including lung, end-stage renal, and cerebrovascular disease. Despite being on chronic therapy, 64.4% had an INR of < 2.0 at baseline.

Treatment patterns also varied. Patients on daily vitamin K antagonists had longer door-to-balloon times, were less likely to receive heparin, prasugrel, or a GPI, and more apt to receive bivalirudin or clopidogrel.

Difference Apparent Even With Adjustment

The chronic therapy group had more in-hospital major bleeding than those not on vitamin K antagonists, even when accounting for differences in baseline characteristics. In addition, bleeding risk did not differ between patients with INR levels above or below the cutoff of 2.0 (P = .08); within the subgroup of patients with INR < 2.0, chronic vitamin K antagonist use also was tied to increased bleeding. Early use of GPIs augmented the ill effect of chronic use, whereas that of bivalirudin curtailed it (table 1).

Table 1. In-Hospital Major Bleeding

According to the researchers, “This is the first study to describe the risk of in-hospital major bleeding among a large cohort of STEMI patients on chronic [vitamin K antagonist] therapy.”

Dr. Karrowni and colleagues note that current US and European guidelines advise waiting to initiate anticoagulants and invasive procedures until INR values drop below 2.0 for NSTEMI patients. “In contrast,” they say, “there are almost no guideline recommendations for acute management of STEMI patients on [vitamin K antagonists], as very limited evidence exists to support bleeding avoidance strategies in this population.”

Given that in-hospital bleeding has been linked to poorer prognosis after acute MI, strategies to reduce bleeding “should be strongly considered,” they say. Some possibilities include greater use of radial access and bivalirudin as well as cautious use of GPIs. 

 


Source:
Karrowni W, Wang TY, Chen AY, et al. Chronic vitamin K antagonist therapy and bleeding risk in ST elevation myocardial infarction patients. Heart. 2014;Epub ahead of print.

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Disclosures
  • Dr. Karrowni reports no relevant conflicts of interest.

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