title: Subcutaneous low molecular weight heparin for management of anticoagulation in infants on excor ventricular assist device.
abstract: Anticoagulation in infants and children on a ventricular assist device presents particular challenges. Unfractionated heparin has poor bioavailability; it can be difficult to achieve a stable anticoagulant effect; and, in the long-term, there is a risk of osteopenia. Long-term warfarin can be difficult to manage in infants on formula milk with vitamin K supplementation. We review our recent experience with subcutaneous low molecular weight heparin. Two patients received a left ventricular assist device (Excor, Berlin Heart AG) as a bridge to transplantation. Initial anticoagulation consisted of unfractionated heparin infusion beginning 6 hours after implantation to maintain an activated partial thromboplastin time of 70 seconds, checked every 4 to 6 hours. Platelet count (aim >80,000/microl) and thromboelastography were assessed daily. Antithrombin required substitution to maintain levels >70 IU/dl. To optimize anticoagulation, both infants were switched to subcutaneous low molecular weight heparin twice daily aiming for an anti-Xa activity between 0.5 and 1.0 IU/ml. Aspirin was added on day 4, checking platelet aggregation every 2 to 4 days, aiming at arachidonic acid stimulated aggregation 10% to 30% of baseline, collagen 100% of baseline. Dipyridamole was added once stability was reached if platelets count exceeded 150,000/microl. There were no clinical thromboembolic or bleeding events. Both patients had successful transplantation.
authors.affiliation: Cardiac Unit, Great Ormond Street Hospital for Children NHS Trust, London, United Kingdom.
authors.forename: Olivier
authors.initials: O
authors.lastname: Ghez
authors.forename: Ri
authors.initials: R
authors.lastname: Liesner
authors.forename: Ann
authors.initials: A
authors.lastname: Karimova
authors.forename: Cho
authors.initials: C
authors.lastname: Ng
authors.forename: Allan
authors.initials: A
authors.lastname: Goldman
authors.forename: Carin
authors.initials: C
authors.lastname: van Doorn
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage*; D000991:Antithrombins / Q000378:metabolism; D015951:Factor Xa / Q000378:metabolism; D005260:Female; D006333:Heart Failure / Q000601:surgery*; D016027:Heart Transplantation; D006353:Heart-Assist Devices; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage*; D006801:Humans; D007223:Infant; D007279:Injections, Subcutaneous; D010314:Partial Thromboplastin Time; D010976:Platelet Count; D013927:Thrombosis / Q000188:drug therapy / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D000991:Antithrombins; D006495:Heparin, Low-Molecular-Weight; D015951:Factor Xa