Differentiation of low molecular weight heparins in acute coronary syndromes: an interventionalist's perspective.

The more predictable and sustained anticoagulant effects of low molecular weight heparins (LMWHs) compared with unfractionated heparin (UFH) has led to increasing interest in their potential use in association with interventional cardiac procedures. Available data demonstrate that dalteparin, nadroparin, reviparin and enoxaparin can be safely used during percutaneous transluminal coronary angioplasty. As yet there is, however, no evidence of a reduction in restenosis. Preliminary evidence indicates that a novel antithrombotic combination of ticlodipine and enoxaparin in association with coronary stenting may reduce the frequency of acute events compared with conventional antithrombotic therapy, although it remains unclear as to whether ticlopidine alone is equally effective. Enoxaparin also reduces the frequency of ischemic events following thrombolytic therapy for acute myocardial infarction, and is the only LMWH to have been shown to reduce the frequency of revascularization procedures in patients with acute coronary syndromes. Some evidence suggests that, in patients with acute coronary syndromes, plaque passivation may be adequately managed using long-term LMWH therapy, rather than immediate intervention, given the potential increase in thromboembolic burden by the interventional procedure. On the basis of available evidence, peri-interventional use of LMWH is broadly feasible. Given the United States Food and Drug Administration's position that LMWHs are distinct noninterchangeable drugs, further trials are needed to establish acceptable protocols and the LMWH of choice. Until that time, interventional cardiologists can rely on available clinical data to choose a LMWH that will simplify patient management and improve patient outcome.