DEATH and in-hospital bleeding in patients with non-ST-segment elevation myocardial infarction (NSTEMI) appears less likely through the use of fondaparinux, a factor Xa inhibitor, compared with low-molecular-weight heparin (LMWH).
These conclusions were drawn from the results of a Swedish registry, which consisted of 14,791 patients with NSTEMI treated with fondaparinux and 25,825 treated with LMWH. Of those who received fondaparinux, 1.1% had a bleeding event and 2.7% died in-hospital, whereas of those who received LMWH 1.8% had a bleeding event and 4.0% died in-hospital, according to the report by Dr Karolina Szummer, Karolinska University Hospital, Stockholm, Sweden and colleagues.
Patients in the fondaparinux group also showed a significantly reduced risk of severe bleeding and mortality at 30 and 180 days when compared with those in the LMWH group. 4.2% and 8.3% of patients treated with fondaparinux died at 30 and 180 days, respectively, compared with 5.8% and 11.8% of patients treated with LMWH. The results confirm the conclusions of the earlier OASIS-5 study that treatment with fondaparinux is associated with a significant reduction in mortality at 30 and 180 days. Patients in the Swedish registry had lower rates of hypertension and a more frequent history of myocardial infarction and stroke compared with OASIS-5.
The rate of severe bleeding was 5-fold greater in patients with impaired renal function, although fondaparinux lowered bleeding rates in-hospital and at 30 days compared with LMWH. However, these results were not statistically significant in those with the most severe renal dysfunction. The authors note that the successful prevention of bleeding may result in reduced mortality.
“However, even though the odds of bleeding were consistently lower across all renal-function categories, the lower mortality with fondaparinux compared with LMWH was not significant in those with worst renal function,” wrote Dr Szummer and colleagues. “This may indicate that the elevated risk of death in those with the lowest renal-function category is explained by other mechanisms unrelated to bleeding.”
While the European Society of Cardiology recommends fondaparinux as a first-choice anticoagulant for acute coronary syndrome patients treated noninvasively or with percutaneous coronary intervention (PCI), in the USA the American College of Cardiology/American Heart Association recommends an anticoagulant for patients with NSTEMI, either fondaparinux or enoxaparin, but only for those not undergoing PCI.