EXTENDING anticoagulant treatment with bivalirudin for at least four hours following completion of PCI did not improve outcomes any better than stopping treatment immediately after the procedure. The MATRIX trial, published simultaneously in the New England Journal of Medicine, provided no clear winner.
Bivalirudin is known to reduce bleeding as compared to unfractionated heparin; but concomitantly increases risk of stent thrombosis. ‘But,’ said study presenter Marco Valgimigli from the Swiss Cardiovascular Centre, Bern, ‘whether prolonging bivalirudin after PCI mitigates ischaemia without increasing bleeding risk is unknown due to a lack of properly controlled randomised trials.’
The Minimizing Adverse Hemorrhagic Events by Transradial Access Site and Systemic Implementation of Angio (MATRIX) study was designed to determine whether bivalirudin given during intervention followed by a post-PCI infusion for at least four hours was associated with reductions in adverse cardiovascular events. The study is part of a series of three randomised trials involving patients with acute coronary syndromes.
Between 2011 and 2014, 3610 patients were randomised to receive bivalirudin either during PCI only (n = 1,188) or both during and after the procedure (n = 1,799). The study, sponsored by the Italian Society of Interventional Cardiology, took place at 78 sites in Italy, the Netherlands, Spain and Sweden.
Rates of the primary outcome (a composite of urgent target vessel revascularisation, definite stent thrombosis, and net adverse clinical events up to 30 days) were 11.0% for patients with post-procedure bivalirudin versus 11.9% for patients who only received bivalirudin during the procedure (RR 0.91, P=0.34). Additionally, no component of the primary end point was found to be reduced in the group receiving prolonged infusions of bivalirudin.
‘The study leaves both options open. There were no safety signals with respect to prolonging bivalirudin - which had been a professional concern,’ said Valgimigli.
The results, wrote the authors, reinforce the concept that reducing the rate of major bleeding events among patients with acute coronary syndromes treated with PCI does not necessarily affect the risk of major ischaemic adverse cardiovascular events. ‘The difference between the findings of this study and other studies may reflect the way in which nonfatal peri procedural ischaemic events and bleeding events were defined,’ they suggest.
Nevertheless, according to an accompanying editorial in the NEJM, ‘the MATRIX trial provides the best evidence to date on the question of whether prolonging the infusion of bivalirudin after the end of the PCI procedure is beneficial’.
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