NSTE-ACS

LMWH and, to a lesser extent, fondaparinux, have taken over from UFH in the management of ACS, but these agents too, although effective, have important limitations. Perhaps the most important limitations of LMWH and fondaparinux are that they have long half-lives and they are renally cleared. In the emergency room, we are really looking for flexibility in terms of treating the patients.

Fondaparinux, is not really suitable for the cath lab because of the issues related to catheter-related thrombosis.

Bivalirudin is the other available agent, and it also has partly replaced UFH. It has a short half-life, but still it does not have an antidote. It still is partially renally cleared. It is relatively expensive, and it is certainly not used across the spectrum of ACS.

There is another agent that has attracted some attention, pegnivacogin (its earlier name was RB006), and its accompanying complementary aptamer, anivamersen, which is a reversal agent. These are ribonucleic acid (RNA) oligonucleotides. They have a unique 3-dimensional structure. They specifically target factor IX; pegnivacogin can selectively block factor IX and achieve effective anticoagulation. The reversal agent, the complementary aptamer, can promptly and completely reverse the effect of pegnivacogin. This combination is extremely attractive, at least in theory, in ACS and certainly has the potential to help replace heparin.