Continuous intravenous infusion of a low-molecular-weight heparin during allogenic haematopoietic stem-cell transplantation.

Low-molecular-weight heparins are routinely administered once or twice daily by subcutaneous injection. With the exception of patients on haemodialysis or presenting with unstable angina or flat Q-wave myocardial infarction, in which short-term intravascular administration is recommended, little information is available regarding the efficacy of continuous intravenous administration of low-molecular-weight heparins. We report the case of a 50-year-old patient who underwent an allogenic haematopoietic stem-cell transplantation for acute myeloid leukaemia. Prior to transplantation, the patient was on long-term oral anticoagulant (acenocoumarol) following the placement of a mechanical aortic valve. Acenocoumarol was stopped and low-molecular-weight heparin (nadroparin calcium) was administered intravenously through a continuous infusion pump (30 000 anti-Xa U/day) starting from day 0 until day 23 after transplantation. The patient was prophylactically transfused with platelets when the daily platelet count fell below 50 x 10 l. Repeated blood measurements showed that a therapeutic level of anti-Xa activity was achieved and maintained at a fairly constant level. No haemorrhagic or thrombotic complications occurred. This observation suggests that intravenous continuous infusion of low-molecular-weight heparin may be an alternative to subcutaneous injections in selected patients who need anticoagulation.