Anticoagulant Bridge Comparison in Mechanical Circulatory Support Patients

Abstract

Maintaining mechanical circulatory support (MCS) device patients in a specified therapeutic range for anticoagulation remains challenging. Subtherapeutic international normalized ratios (INRs) occur frequently while on warfarin therapy. An effective anticoagulant bridge strategy may improve the care of these patients. This retrospective review of MCS patients with subtherapeutic INRs compared an intravenous unfractionated heparin (UFH) strategy with a subcutaneous enoxaparin or fondaparinux strategy. Native thromboelastography (n-TEG) was used to evaluate anticoagulant effect with coagulation index (CI) as the primary outcome measure. Enoxaparin 0.5 mg/kg SC q12hrs or fondaparinux 2.5-5 mg SC daily were compared with an initial UFH rate of 5 units/kg/hr and titrated to stated n-TEG goal range. The anticoagulant groups UFH, enoxaparin, and fondaparinux were found to be statistically similar with regard to frequency in n-TEG goal range, above range (hypercoagulability), or below range (hypocoagulability). Clinical outcomes were similar among groups with three gastrointestinal bleeds in UFH, one in enoxaparin, and one in fondaparinux groups. Device thrombosis occurred in one UFH patient, while UFH and fondaparinux groups had one ischemic cerebrovascular accident event each. These strategies provided comparable n-TEG results and clinical outcomes when compared with intravenous UFH. Low-dose enoxaparin or fondaparinux may provide an alternative anticoagulant bridging option in MCS patients presenting with subtherapeutic INR.

Unfractionated and Low-Molecular-Weight Heparin for Bridging Patients with Left Ventricular Assist Device: An Event-Based Analysis

“…21 To date, however, data available to evaluate the safety and efficacy for bridging with UFH, and in particular LMWH, in the LVAD population is limited and with mixed results. 13–18…”

“…21 To date, however, data available to evaluate the safety and efficacy for bridging with UFH, and in particular LMWH, in the LVAD population is limited and with mixed results. [13][14][15][16][17][18] To address the limited data regarding appropriate bridging strategies in patients with LVADs, this study aimed to critically examine the safety and efficacy, characterized by major bleeding events and thrombotic events, respectively, of using LMWH or UFH for bridging in patients with an LVAD. Both UFH and NB episodes were used as comparator groups.…”

“…11,12 Small retrospective trials examining the use of low-molecular-weight heparin (LMWH) versus no anticoagulation during both the immediate postimplant period and anytime afterward show mixed results, with some reporting increased risk of major bleeding events. [13][14][15][16][17][18] To our knowledge, no trial to date has compared the use of LMWH to UFH for bridging in patients with LVADs with subtherapeutic INRs after the index hospitalization. The objective of this study was to further examine the safety and efficacy of UFH and LMWH for bridging in patients with an LVAD.…”

Anticoagulant treatment and bleeding complications in patients with left ventricular assist devices

“…The most practical strategy to reduce the need for bridging is to lower the threshold for subtherapeutic INR levels. Such a strategy has been investigated in a recent small observational study where LVAD patients were not bridged unless INR levels were below 1.8 [56]. In addition, reduced doses of enoxaparin (0.5 mg/kg twice daily) or fondaparinux (2.5 mg once daily) were used.…”

Enoxaparin Use and Adverse Events in Outpatients With a Continuous Flow Left Ventricular Assist Device at a Single Institution

“…Initial studies supported the use of enoxaparin as a bridging strategy compared to no bridging or intravenous heparin for inpatients bridging immediately post-operatively or readmitted for a subtherapeutic INR. 6,7 However, the evidence regarding outpatient enoxaparin use in LVAD patients is scarce and conflicting. Single center studies have evaluated the use of half-therapeutic or full-therapeutic dose with varying lengths of enoxaparin bridging, without a consensus of impact on patient outcomes.…”