Low-molecular-weight heparin beats unfractionated in STEMI

 A new meta-analysis has found that low-molecular-weight heparins (LMWHs) are associated with a reduction in mortality and major bleeding rates in STEMI patients treated with primary PCI as compared with unfractionated heparin (UFH) [1]. And patients at greatest risk seem to derive the most benefit from LMWHs, report Dr Eliano Pio Navarese (Nicolaus Copernicus University, Bydgoszcz, Poland) and colleagues in their paper published online July 20, 2011 in the Journal of Thrombosis and Haemostasis.

 

UFH has generally been recognized as the standard anticoagulant for use in STEMI patients undergoing primary PCI, and current AHA/ACC and European Society of Cardiology (ESC) guidelines recommend the use of UFH in this setting, Navarese. And althoughpreliminary data from the ATOLL study, which is not yet published, show the efficacy and safety of the LMWH enoxaparin for this use, ATOLL was underpowered to assess the effect of LMWHs on a single outcome such as mortality, he explained.

"But based on our meta-analysis, I would say a new scenario could be envisaged in which LMWH may be considered as a preferred anticoagulant among these patients."

He added that, to date, there has been no comparison of LMWHs with another newer strategy for primary PCI in STEMI, the use of bivalirudin (Angiomax, the Medicines Company), "which in HORIZONS-AMI has been shown to be superior to UFH and GP IIb/IIIa inhibitors in STEMI. This is a black hole we have to date. However, I am not convinced that bivalirudin spells the end of other anticoagulants in PCI for STEMI, as some uncertainty remains in the early phase of primary PCI, when thrombotic complications seem to be higher with bivalirudin monotherapy."

But Navarese says, in any case, ideally, "the next step should be to move toward personalized anticoagulant therapy in primary PCI, where a stratification of thrombotic and bleeding risk of each patient could guide the choice of the proper anticoagulant regimen."