Bivalirudin in Briefer PCI May Boost Stent Thrombosis Risk

By David Douglas

NEW YORK (Reuters Health) - Shorter percutaneous coronary intervention (PCI) procedures are associated with an increased risk of acute stent thrombosis (AST) in patients treated with bivalirudin, according to a secondary analysis of a randomized clinical trial.

Given these findings, Dr. Duane S. Pinto told Reuters Health by email, "additional studies are needed to evaluate antithrombotic therapies with different pharmacokinetics."

As reported March 1 online in JAMA Cardiology, Dr. Pinto of Beth Israel Deaconess Medical Center, Boston, and colleagues studied 1,286 such patients who received bivalirudin and 1,412 who received heparin plus a glycoprotein IIb/IIIa receptor inhibitor (GPI) in the HORIZONS-AMI trial.

During follow-up for up to three years, bivalirudin use was associated with less major bleeding, thrombocytopenia and mortality but with a higher risk for AST, compared with heparin and GPI.

All stent thromboses occurred after the procedure and definite AST was more likely in bivalirudin patients in whom procedures were shorter than 45 minutes (2.1%) than in those with longer procedures (0.7%).

This was despite the fact that patients undergoing shorter procedures were younger and less likely to be hypertensive and smokers. Shorter procedures were also less complicated, with fewer stents implanted and less multivessel stenting.

The median procedure time for bivalirudin-treated patients with AST was 49 minutes, compared to 60 minutes for such patients without AST.

There were no instances of AST in the heparin patients during shorter procedures. AST developed in only three patients (0.3%) during longer procedures.

There were no substantial differences in stent thrombosis between the treatment groups from one to 30 days and from one to three years postoperatively.

The team suggests that when the procedure is completed rapidly, "adequate antiplatelet effect may not have been achieved with oral agents, particularly if gastrointestinal tract absorption has been slowed in ST-segment elevation myocardial infarction."

The half-life of bivalirudin is 25 minutes. Dr. Pinto concluded, "The risk of stent thrombosis may increase during fast procedures given bivalirudin¹s short half life especially without prolonged infusion or adequate anti-platelet effect."

He and his colleagues call for "additional studies evaluating strategies aimed at mitigating this effect, including a high-dose prolonged bivalirudin infusion or intravenous cangrelor.”

Commenting by email, Dr. Dmitriy N. Feldman, director of endovascular services at Weill Cornell Medicine / New York-Presbyterian Hospital in New York City told Reuters Health that the results “support the hypothesis that bivalirudin use in STEMI can lead to a 'vulnerable period' after PCI. This vulnerable period occurs due to lack of antithrombotic effects because of a short half-life of bivalirudin and due to lack of P2Y12 inhibition because of delayed onset of platelet inhibition with oral agents in the setting of STEMI."

Because of this, he concluded, "strategies to mitigate such a vulnerable period should be pursued (e.g. prolonged high-dose bivalirudin infusion)."

SOURCE: https://bit.ly/2n2Qkpc

JAMA Cardiol 2017.

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