Rates of short- and long-term mortality after an acute coronary syndrome (ACS) have been reduced dramatically through advances in percutaneous coronary intervention (PCI) techniques and the availability of new antithrombotic agents. This is particularly true for patients with ST-elevation myocardial infarction (STEMI) treated with primary PCI. On the antiplatelet side, we have, besides clopidogrel, two new P2Y 12 inhibitors – prasugrel and ticagrelor – for which data and subset analyses have allowed a better understanding of which patients with an ACS would truly benefit from these drugs. On the anticoagulant side, besides unfractionated heparin (UFH), we have three newer anticoagulants that can be used in ACS: enoxaparin, fondaparinux and bivalirudin. In this competitive field, the past decade has provided a large flow of evidence-based information in terms of the safety and efficacy of these antithrombotic agents. This information needs to be implemented both in guidelines and in our daily clinical practice. As always, there is no simple rule or conclusion; rather, different options exist according to current practice and our own personal environment and experiences.
The efficacy of anticoagulation therapy is evaluated on the basis of ischaemic complications of ACS and sometimes the outcome of PCI itself, both of which have a real impact on short- and long-term mortality. The first goal of anticoagulation therapy during primary PCI of STEMI is therefore to avoid or control at all times the development of thrombus and in doing so obtain or maintain blood flow through the coronary circulation and protect the myocardium from harmful damage related to ischaemia and necrosis. If the drug efficacy translates into a mortality reduction, there is a good chance of recognition and acceptation of the new treatment by practising physicians.
Safety is also a major issue of anticoagulation therapy: all of these drugs increase the risk of instrumental or spontaneous bleeding, leading to more transfusions and subsequently higher morbidity and mortality . Lowering instrumental or procedure-related bleeding is very important; when interventional cardiologists are not sufficiently skilled to perform PCI through the radial approach, this reduced bleeding risk can be achieved with the use of a more stable anticoagulant and a lower level of anticoagulation.
The latest data on the efficacy (ischaemic and mortality endpoints) and safety (major bleeding endpoint) of the three newest anticoagulants – enoxaparin, fondaparinux and bivalirudin – tested in primary PCI for patients with STEMI are provided in Table 1 .
| Authors | Study | Anticoagulant | Patients ( n ) | Ischaemic | Major bleeding | All-cause mortality |
|---|---|---|---|---|---|---|
| Silvain et al. | Meta-analysis (primary PCI) | Enoxaparin | 10,243 | 0.76 a (0.60–0.96) | 0.72 a (0.56–0.93) | 0.52 a (0.42–0.64) |
| Montalescot et al. | ATOLL | Enoxaparin | 910 | 0.59 a (0.38–0.91) | 0.92 (0.51–1.66) | 0.60 (0.33–1.07) |
| Stone et al. | HORIZONS | Bivalirudin | 3602 | 1.00 (0.75–1.32) | 0.60 a (0.46–0.77) | 0.66 a (0.44–1.00) |
| Yusuf et al. | OASIS 6 (primary PCI) | Fondaparinux | 3789 | 1.20 (0.91–1.57) | 1.18 (0.63–2.22) | 1.16 (0.85–1.58) |
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