Venous thromboembolism

1. Venous thromboembolism

2. Pathophysiology
Pregnancy is associated with a 6–10-fold increase in the risk of VTE
Virchow's triad : Hypercoagulation , stasis , vascular injury
Hypercoagulation in pregnancy : increase in clotting factors VIII, IX, X and fibrinogen
levels, and a reduction in protein S and antithrombin (AT) III concentrations

3. Pathophysiology
Venous stasis in pregnancy :venous stasis in the lower limbs due to the weight of
the gravid uterus placing pressure on the IVC in late pregnancy and immobility,
particularly in the puerperium.
The most common cause of direct maternal death in the developing countries

4. Risk
factors

5. Thrombophilia (1)
Can be inherited or acquired
Inherited as :
deficiencies of the endogenous anticoagulants protein C, protein S and AT III
abnormalities of procoagulant factors, factor V Leiden (caused by a
mutation in the factor V gene) and the prothrombin mutation G20210A
•Acquired : as antiphospholipid syndrome

6. Thrombophilia (2)
more than 50% of women with pregnancy-related VTE will have a
thrombophilia
Screening for thrombophilia should be carried out in those with a
strong family or personal history of VTE.

7. Diagnosis of APS

8. Diagnosis of DVT
Symptoms and signs : pain , redness , swelling ,
hotness , tenderness
First investigation : Compression ultrasound
If ultrasound is normal but you highly suspect
DVT, repeat ultrasound after 3-7 days

9. Pulmonary embolism
Symptoms : breathlessness , chest pain , tachycardia , tachypnea , mild fever ……
Initial investigation : electrocardiogram (ECG), chest X-ray and arterial blood gases
If signs of DVT also present : do compression ultrasound and treat if positive …
•If all tests are normal but high suspicion : CTA , V/Q scan

10. Pulmonary embolism
•If chest x ray is abnormal CTA is preferred to rule out other chest pathology
•CTA has more radiation risk on maternal breast while VQ scan carries a slightly
higher risk on the baby ( risk of childhood cancer )
Importantly, both CTA and VQ scan are below the threshold potentially
dangerous to the fetus
D DIMER is not reliable in pregnancy

11. Treatment of VTE
Drug of choice in pregnancy : LMWH (for treatment and prevention)
Both warfarin and LMWH are safe in women who are breast feeding
Newer anticoagulants such as fondaparinux (a direct factor Xa inhibitor) are
not licensed for use in pregnancy and experience with them is limited
Graduated elastic stockings should be used for the initial treatment of DVT
and should be worn for 2 years following a DVT to prevent post-thrombotic
syndrome.

12. 
Rapid treatment of suspected VTE
in pregnancy should be
commenced while awaiting
diagnosis