232 Comparative efficacy and safety of enoxaparin and fondaparinux in non-high risk acute pulmonary embolism: an adjusted propensity score analysis

Abstract

Guidelines recommend low molecular weight heparin (LMWH) and fondaparinux (fonda) over unfractionated heparin (UFH) for initial treatment of acute pulmonary embolism (PE), except in patients (pts) at high risk of bleeding & with severe renal dysfunction. No trial has assessed the comparative efficacy of enoxaparin (enox) and fonda in this setting. Prospective, multicenter registry. Pts with proven recent PE (symptom onset <15 days), treated with approved regimens of enox or fonda were included. Pts with high risk PE, and those with recent or active bleeding, recent surgery or stroke, or renal failure were excluded. We calculated a propensity score by logistic regression (i.e. predicted probability of treatment by enox as opposed to fonda). Combined in-hospital endpoint was defined as death, recurrent PE or major bleeding. Secondary endpoints were residual pulmonary vascular obstruction (RPVO) at discharge and 6 m, and 6 m mortality. Of 501 pts included between 2006 and 2010, 229(46%) received enox and 272 (54%) received fonda. 5(2.2%) pts under enox had recurrent PE vs 5 (1.8%) fonda pts (p = 0.96). 13(5.7%) enox pts and 9(3.3%) fonda pts had major bleeding (p = 0.19), in-hospital mortality was 3.5% and 1.1% respectively (p = 0.07). During in-hospital stay, 19(8.3%) of pts treated with enox reached at least 1 clinical endpoint vs 12(4.4%) fonda pts (p = 0.07). After adjusting on propensity score, there was no significant difference in death, recurrent PE, major bleeding or combined endpoint (enox vs fonda, OR = 1.45 [0.67–3.14]). RPVO at discharge was 28.4 ± 14.6% in enox vs 27.2 ± 13.9 in fonda pts (p = 0.57). There was no difference in RPVO at 6 m. The 6 m mortality rate was 8.5% in enox pts vs 9.3% in fonda pts (p = 0.76). Our results suggest that enox and fonda can be used interchangeably, as efficacy and safety profiles are comparable in non-high risk acute PE patients. Neither molecule appears to induce an excess bleeding risk as compared to the other.