TE in pregnancy

Thromboembolism (TE)

Thromboembolism is one of the problems that may complicate pregnancy and the postpartum period is the commonest time in pregnancy for a thromboembolism.
What are the risk factors for venous TE in pregnancy includes:
1 Increased coagulation. The increase in clotting factors in pregnancy lead to predominance of thrombosis over fibrinolysis.
2 Stasis. Many women have been immobilized in pregnancy, during labour or the immediate puerperium, and by the pressure of the gravid uterus on the lower limb circulation.
3 Damage to venous endothelium.
• Uterine veins—following uterine sepsis.
• Deep leg veins—weight of legs compresses veins if immobilized.
4 operative delivery: 20 times risk after C/S.
5 congenital thrombophilia: e.g. protein C deficiency and antithrombin III deficiency.
6 antiphospholipid syndrome: with anticardiolipin and lupus anticoagulant antibody.
7 miscellaneous factors: age >35 years, grand multiparity, obesity, smoking, sickle cell disease, previous TE, prolonged bed rest.


Diagnosis


Clinical features:
1 superficial thrombophlebitis
2 DVT
3 pulmonary TE (PTE)
The 1st one may present in pregnancy and puerperium and limited to the superficial saphenous system leading to superficial varicosity presenting with redness, tenderness, and edema of the affected area. There is no immediate hazard to PTE treated by analgesia, active movement of the affected limb, and elastic support.


Symptoms of DVT:
1 More than 50% are asymptomatic and may progress to PE.
2 severe pain in the lower limb.

Signs:
1) Pale extremity from reflex arterial spasm.
2) Edema and swelling of the affected part.
3) Increased local temperature.
4) Positive Homan s sign (calf tenderness on dorsiflexion of the foot).
5) Low-grade postpartum pyrexia.
6) An unexplained maternal tachycardia

INVESTIGATIONS:
1) ultrasound: either Doppler or real time
• Simple continuous wave Doppler ultrasound will fail to show flow in the femoral vein, it is not useful in DVT below the knee.
• Colour flow Doppler may demonstrate the clot in the veins.
2) Venography.
• This is the definitive test using image intensifiers and low-viscosity contrast medium.
3) isotope venography (gold standard in the diagnosis of DVT).
4) MRI. Used in the diagnosis of symptomatic DVT.

Management
PREVENTION
1 Early mobilization—all women are encouraged to be up as soon as they wish. Non-weight-bearing exercises used for postoperative mothers.
2 Prophylaxis is usually given to women who have had a previous history of TE or are at moderate to high risk.
• Compression stockings worn during labour or Caesarean section.
• Subcutaneous low molecular weight heparin (LMWH).

TREATMENT OF DVT:
Consist of 3 factors anticoagulation, rest and analgesia:

Acute phase:
1 Anticoagulate immediately:
(1) with full dose i.v. UH: to prevent further extension of the thrombus with the risk of pulmonary embolism and allows earlier recanalization of the clotted veins.
Heparin is the best one in the acute phase: because it exhibit both antithrombotic and anticoagulant actions:
Heparin is given initially 10,000 IU as bolus dose i.v. then followed by 30,000-40,000 IU over the next 24 hours as continuous infusion or repeated doses every 2-3 hours because of the short half life of heparin.
This therapeutic dose should be continued for 5-10 days until signs and symptoms resolved, this treatment require monitoring by APTT which should be 1.5-2 times the lab control, if bleeding occur heparin should be stopped and it will be cleared from circulation within 6 hours but if severe bleeding occur give protamine sulphate 1-2 mg for each 100 IU and if not responding give FFP.

{ if labor started:
*stop heparin. And at least 2 hours after delivery and if the uterus is well contracted reinstitute heparin.
* reverse effect of heparin by protamin sulphate.
*avoid epidural anesthesia.
Of the advantages of heparin: it does not cross the placenta, rapidly removed from the circulation.
But: it cause bruising and bleeding with therapeutic doses, thrombocytopenia, allergic reactions, and if prolonged use (>6 months) ?osteopenia may occur}

(2) Thrombolytic agents:
Streptokinase and urokinase are alternative to heparin especially in case of iliofemoral thrombosis.

(3) Surgery:
Thrombectomy is indicated when there is gross swelling enough to cause venous gangrene.

Chronic case:
Then the patient after the subsidence of the acute phase should be treated as chronic case and should take subcutaneous heparin (prophylaxis dose 5000 IU 2-3 times per day and it does not need monitoring because the APTT is not altered) this dose does not interfere with hemostasis.
Or give oral warfarin instead which is started in the 6-7th days of heparin treatment and the dose adjustment is by the PT and the INR, the therapeutic effect is achieved in the 5th day of the treatment, it inhibit the vit. K dependent factors: II, VII, IX, X. Treatment must be continued for at least 6-12 weeks postpartum or 6 months after the initial insult.
Warfarin crosses the placenta and causes congenital anomalies in the 1st trimester use namely the chondrodysplasia punctate, microcephaly, also increase incidence of abortion and IUD, fetal optic atrophy, mental retardation. AND causes maternal bleeding.

Pulmonary embolism
The most dangerous form of a clot embolus from the leg or pelvic veins is in the pulmonary circulation, the incidence of PTE 1/2700- 1/7000 deliveries.

Clinical presentation:
1 Mild cases following microemboli: Dyspnoea and slight poorly defined pleural pain. The condition resolves in a few days with no specific treatment and may not even be diagnosed; its diagnosis can be made by high index of suspicion.
2 Severe cases arise from clot from the:
• Soleal veins—clot extends to popliteal vein and breaks off (30%).
• Uterine and ovarian veins—a thrombophlebitis with a friable clots following midpelvic sepsis (20%).In 50%, no clinical signs of the origin exist before the pulmonary embolism.
Diagnosis
HISTORY
History of Pre-existing deep vein thrombosis (in half the cases only).

Early:
• Acute dyspnoea.
• Faintness.

Later:
• Chest pain.
• Haemoptysis.

EXAMINATION
• may be no physical signs beyond dyspnoea.
• Cyanosis.
• Local signs of pulmonary under perfusion.
• Right heart failure, raised JVP.
• Tachypnea.
• Pleural signs.
• Collapse of a pulmonary lobe.

INVESTIGATIONS: Often no positive tests early.
Next day:
1) X-ray:
• Raised diaphragm on affected side because of collapsed lobe.
• Consolidation and infiltration of lung(s).
2) ECG—rhythm disturbance.
• Lead I—S wave inversion.
• Lead III—T wave inversion and deep Q wave.
• Leads VI, 2, 3, 4—T wave inversion.
• Excludes cardiac infarction.
3) Lung ventilation–perfusion scan {V/Q} with radioactive albumin to show ischemic areas.
4) Pulmonary angiography with shielding of the abdomen to show clot is the gold standard investigation in diagnosing PE.
5) Recent advance is by utilization of contrast spiral CT scan which is highly sensitive for detection of clot in the pulmonary artery.

Management:
Two-thirds of those dying do so within 2 hours, so act quickly on suspicion, not awaiting the sophisticated tests even if they are available.

IMMEDIATE TREATMENT
1 External cardiac massage if required.
2 Positive pressure O2 by intubation if necessary.
3 Heparin (see below).
4 Emergency embolectomy is only performed in hospitals with their own thoracic units with bypass facilities and rarely used.

DEFINITIVE TREATMENT
If resuscitation is successful, give:
1) Anticoagulants (i.v. heparin):
• 20,000 units immediately.
• Treatment course is the same as in acute DVT, this is to prevent further emboli.
At the same time start warfarin oral therapy controlled by PT and INR.
2) Thrombolytics (streptokinase). Actively accelerate lysis of existing clot:
3) Embolectomy (mortality rate 0.5%)
Useful if:
• Thoracic unit in the same hospital.
• No response to streptokinase.
• Too ill for streptokinase.
• Contraindication to streptokinase, e.g. recent surgery, peptic ulcer or hypertension.
Both high-dose heparin and streptokinase have high risk of starting bleeding. Not indicated unless embolus is thought to be life-threatening.

INDICATIONS FOR PROPHYLAXIS TREATMENT DURING PREGNANCY:
To prevent DVT/ TE in patients at risk:
1) Patient with previous TE ? risk of recurrence.
2) Patients with cardiac disease especially artificial heart valves.
3) Patient with: congenital thrombophilia, obesity (>80 kg), age >35 y, prolonged bed rest, operative delivery.

Drugs to be used for prophylaxis are either:
1) UH 5000-7000 IU (2-3) times daily.
2) LMWH either fragmin 5000 IU / day or enoxaparin 40 mg/day (4000 IU).
3) Warfarin.
4 antiplatelets: low dose aspirin 75mg/day, it prevent arterial and venous thrombosis without fetal harms.