Low-molecular-weight heparin for thromboprophylaxis in pregnant women with mechanical heart valves |
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Authors: | Andra H. James MD Leo R. Brancazio Thomas R. Gehrig Andrew Wang Thomas L. Ortel |
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Affiliation: | 1. Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC, USAandra.james@duke.edu;3. Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC, USA;4. Division of Cardiology, Duke University Medical Center, Durham, NC, USA;5. Division of Hematology, Department of Medicine, Duke University Medical Center, Durham, NC, USA |
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Abstract: | Background.?Pregnancy in a woman with a mechanical heart valve is a life-threatening situation. Due to the inability of unfractionated heparin to prevent valvular thromboses, warfarin or other vitamin K antagonists have been the preferred anticoagulants for the mother. They are, however, potentially harmful to the fetus. With the advent of low-molecular-weight heparins, clinicians were hopeful for an alternative that was safe for the fetus, but more effective than unfractionated heparin, which carries a 29–33% risk of life-threatening thromboses and a 7–15% chance of mortality. Unfortunately, fatal thromboses have occurred with low-molecular-weight heparin as well.Methods.?We searched the MEDLINE database and other sources to identify cases of the use of low-molecular-weight heparin for thromboprophylaxis in women with mechanical heart valves.Results.?We found 73 cases and added three of our own for a total of 76. There were 17 thrombotic events (22%). Thirteen were valve thromboses, two were strokes, and two were myocardial infarctions. There were three deaths (4%).Conclusions.?While pregnant women with mechanical heart valves who receive low-molecular-weight heparin for thromboprophylaxis are at extremely high risk of life-threatening thromboses, there is no evidence that low-molecular-weight heparin is inferior to unfractionated heparin. |
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Keywords: | Mechanical heart valve pregnancy low-molecular-weight heparin |
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