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How long should a patient continue anticoagulation and should she continue during pregnancy?

December 30, 2021
Jean Marie Connors, MD
Assistant Professor, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts

This month, Jean Marie Connors, MD, discusses how long a 31-year-old patient should continue anticoagulation and the recommendations for pregnancy.


A 31-year-old female, who had a recent miscarriage at six weeks of pregnancy, was participating in boot camp. She developed sudden onset left arm pain and numbness and was found to have brachial and axillary artery thromboses. She underwent an emergent thrombectomy. She was noted to have a dual brachial system, and a subacute thrombus was removed. An ECHO was negative for cardiac thrombus or defect. Her angiogram was negative for stenosis or dissection. A hypercoaguable workup was negative. The patient was placed on rivaroxaban; she wants to conceive again as soon as she can. How long should she continue anticoagulation, and any recommendations regarding pregnancy?


This young woman with high estrogen state presented with acute arterial thrombosis of the left upper extremity while participating in high-intensity exercise at "boot camp," which likely involved upper extremity exercise. She was appropriately treated with an emergent thrombectomy to restore arterial blood flow and placed on anticoagulation with rivaroxaban.

Effort-induced thrombosis is a syndrome of upper-extremity thrombosis in young patients following vigorous exercise. It involves significant use of the arms, such as might occur in long-distance swimming, pitching, gymnastics, or other sports. Paget–Schroetter syndrome is a disease associated with these types of thrombotic complications, which occur more commonly as venous events, than arterial events. In young patients, both effort-induced venous and arterial thromboses are usually the result of thoracic outlet syndrome, which must be considered in this patient. With thoracic outlet syndrome, anatomic variations of the structures in the thoracic outlet can result in compression of the axillary or subclavian arteries, veins, or nerves, with resultant thromboses. These variants can include cervical ribs and other boney abnormalities, as well as variations in muscle anatomy that affect the size of the space that the vessels traverse.

This patient should be evaluated for the presence of a cervical rib, as it is found in more than 90 percent of young patients with arterial thoracic outlet syndrome. Imaging that has already been performed can be reviewed for the presence of a cervical or anomalous rib, but often specific arm positioning is needed to demonstrate compression. If this patient is found to have a bony abnormality, surgical thoracic outlet decompression should be performed, as the rate of recurrent arterial thrombotic events is high. If an anatomic defect can be corrected, then the risk of recurrence is dramatically lowered and three months of anticoagulation is sufficient, without the need to continue anticoagulation during pregnancy.

Rivaroxaban is a small molecule and likely crosses the placenta; its use is contraindicated in pregnancy. The hypercoagulable state post-early miscarriage might have contributed to the development of the arterial thrombotic event, in addition to thoracic outlet syndrome. You could consider testing for antiphospholipid antibodies if evaluation for thoracic outlet syndrome is negative.

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Disclaimer: ASH does not recommend or endorse any specific tests, physicians, products, procedures, or opinions, and disclaims any representation, warranty, or guaranty as to the same. Reliance on any information provided in this article is solely at your own risk.


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