Patients hospitalized with non–ST-segment myocardial infarction who received fondaparinux had significantly lower risk of suffering a major bleed or dying in the hospital, compared with those treated with low-molecular-weight heparin, investigators reported online Feb. 17 in JAMA.
The differences persisted 1 and 6 months after hospitalization, said Dr. Karolina Szummer at Karolinska University Hospital in Stockholm, and her associates. However, fondaparinux was not linked to lower rates of stroke or recurrent heart attack, compared with low-molecular-weight heparin (LMWH), the researchers said.
The European Society of Cardiology changed its NSTEMI guidelines in 2011, recommending fondaparinux as a first-choice anticoagulant for both patients treated either noninvasively or with PCI, spurring a “rapid switch” from LMWH to the indirect factor Xa inhibitor fondaparinux for treating non–ST-segment myocardial infarction (NSTEMI), said the investigators. (American Heart Association/American College of Cardiology guidelines, issued in 2012, do not favor fondaparinux over LMWH.) To study the effects of ESC’s change, they analyzed registry data from 40,616 patients hospitalized with NSTEMI between 2006 and 2010, of whom 36% of patients received fondaparinux and 64% received LMWH (JAMA 2015 Feb. 17;313:707-16).
Only 3.7% of the fondaparinux group suffered severe bleeding events or died in the hospital, compared with 5.5% of the heparin group (adjusted odds ratio, 0.67; 95% confidence interval, 0.58-0.78), the study found. Significant differences in bleeding and death rates persisted 30 days and 6 months after hospitalization, but rates of recurrent heart attack and stroke were similar between the treatment groups at all time points, the researchers said.
“This is not a randomized trial; therefore, residual confounding is very likely,” the investigators cautioned, adding that because the study used registry data, it probably underestimated bleeding events.
The work was funded by the Swedish Foundation for Strategic Research, the Swedish Heart and Lung Foundation, ALF Medicin, and the Swedish Medical Research Council. Dr. Szummer has received lecture fees from AstraZeneca. One coauthor reported financial relationships with GlaxoSmithKline, which markets fondaparinux. Other coauthors reported funding from numerous pharmaceutical companies.