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.
Thrombosis within the membrane oxygenator (MO) during extracorporeal membrane oxygenation (ECMO) can lead to sudden oxygenator dysfunction with deleterious effects to the patient. The purpose of this study was to identify predictors of circuit exchange during ECMO. This is a single-center, retrospective study of all patients who received ECMO at our institution from January 2010 to December 2015. Changes in potential markers were compared on Day 3 vs. Day 0 before MO exchange. Of the 150 patients who received ECMO, there were 58 MO exchanges in 35 patients. Mean ECMO duration was 21.1 (±12.7) days. D-dimer (DD) (μg/mL) (mean difference −2.6; 95% confidence interval [CI]: −4.2 to −1.1; p = .001) increased significantly in the 3 days leading up to MO exchange, whereas fibrinogen (mg/dL) (mean difference 90.7; 95% CI: 41.8–139.6; p = .001), platelet (PLT) count (1,000/μL) (mean difference 23.3; 95% CI: 10.2–36.4; p = .001), and heparin dose (units/h) (mean difference 261.7; 95% CI: 46.3–477.1; p = .02) decreased. Increasing DD or decreasing fibrinogen, PLT count, or heparin dose may indicate an impending need for MO exchange in patients receiving ECMO. Early identification of these changes may help prevent sudden MO dysfunction.
Device thrombosis is a devastating complication of left ventricular assist devices. The definitive treatment has been device exchange or explant. Evidence of increasing morbidity and mortality with device exchange has shifted strategies toward conservative management. In this report, we detail the use of thrombolytics as salvage therapy in a patient with an occlusive HeartWare ventricular assist device (HeartWare Inc., Framingham, MA) thrombus, resulting in long-term survival without further intervention.
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