• Temple EM

Venous Thromboembolic Disease and Pregnancy

Venous Thromboembolic Disease and Pregnancy

Gabriela Guez

The Article: Marik, P.E., Plante, L.A.; “Venous Thromboembolic Disease and Pregnancy”. NEJM 2008. 359:2025-2033.

The Idea: Diagnostic algorithm for suspected DVT and PE during pregnancy.

The Study: This paper provides a diagnostic algorithm to approach the work-up for DVT and PE in pregnancy. If there is suspicion for either diagnosis, LMWH should be started right away. Compression ultrasonography should be performed first as it is without risk to the patient and is 97% sensitive & 94% specific for the diagnosis of symptomatic proximal DVT. If ultrasound is positive, continue LMWH. In the DVT pathway, if the ultrasound is negative, they recommend sending a d-dimer. A negative d-dimer might be helpful to rule out DVT. A positive d-dimer should prompt one to consider iliac-vein thrombosis. The need for high pressure to compress the femoral vein or the absence of flow on Doppler is suggestive of the diagnosis. If suspicion is high, one should pursue Magnetic Resonance Direct Thrombin Imaging or a pulsed Doppler study. If suspicion is low, repeat compression ultrasonography in 5-7 days. If it is positive for DVT at that time, restart LMWH. In the PE pathway, if the ultrasound is negative, they recommend getting a chest x-ray. If the x-ray is normal, they suggest either CTPA or VQ scan. If the x-ray shows an abnormality or if the patient has asthma, get a CTPA. VQ scanning delivers a higher fetal dose of radiation with a slightly higher risk of childhood cancer in offspring; perfusion scanning alone will decrease the radiation dose. CTPA delivers a higher dose of radiation to the mother. Lifetime risk of maternal breast cancer is 13% greater with CTPA than VQ scan. If imaging is normal, the patient can follow up as needed. If positive, restart LMWH. If imaging is non-diagnostic and there is still high suspicion, pursue other imaging modalities such as pulmonary angiography, serial compression ultrasonography, MRDTI, or pulsed Doppler study. When anticoagulating the patient is indicated, because of increased renal excretion of LMWH in pregnant patients, twice-daily weight-based regimens have been recommended.

Takeaway: In the diagnosis of DVT or PE in pregnancy, always perform compression ultrasonography first because if that’s positive, you can initiate treatment without need of further work-up or imaging. In evaluation of DVT, if the ultrasound is negative, send a d-dimer and if positive, consider repeat US in 1 week or pursue imaging for iliac vein thrombosis. Treat with LMWH if positive for DVT. In evaluation of PE, if the ultrasound is negative, get a CXR. If CXR abnormal, get a CTPA (higher radiation to mom). If normal, get a VQ scan (higher radiation to fetus) or a CTPA. When anticoagulation, administer LMWH twice daily given higher renal excretion in pregnant women. Although this article provided a useful algorithm to refer to, it does not explain or provide evidence behind the creation of the algorithm. Furthermore, it does not state in which setting this algorithm is to be applied to (ER vs inpatient vs outpatient), why d-dimer is only used in the DVT pathway, and why asthma serves as a reason to obtain a CTPA when evaluating for PE. Other literature can supplement & serve as references for the diagnosis and management of venous thromboembolism in pregnancy.

#ObstetricsGynecology #ThoracicRespiratory

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