[30] Thromboembolic Disease Flashcards
What is meant by VTE?
It is a collective term that describes DVT and PE
Why is VTE important in pregnancy?
Pregnancy is a major risk factor for VTE, resulting in 4-5x increased risk
Why is there an increased risk of VTE in pregnancy?
Thought to be due to changes in levels of some of the proteins in the clotting cascade
What changes are there in the clotting cascade during pregnancy?
- Increased fibrinogen
- Decreased protein S
What happens to the changes in the clotting cascade as the pregnancy progresses?
They become more pronounced
What is the period of highest risk for VTE in pregnancy?
Post-partum
Describe the relationship between VTE and maternal mortality in the UK
It is the leading cause of maternal mortality in the UK, responsible for 1/3 of maternal deaths
What can the additional risk factors for VTE in pregnancy be divided into?
- Pre-existing factors
- Obstetric factors
- Transient factors
What are the pre-existing risk factors for VTE in pregnancy?
- Thrombophilia
- Medical co-morbidities
- Age >35
- BMI >30
- Parity >3
- Smoking
- Varicose veins
- Paraplegia
Give an example of a pre-existing cause of thrombophilia
Anti-phospholipid syndrome
Give an example of a medical co-morbidity that can increase the risk of VTE
Cancer
What are the obstetric risk factors for VTE?
- Multiple pregnancy
- Pre-eclampsia
- C-section
- Stillbirth
- Preterm birth
- PPH
What are the transient risk factors for VTE?
- Any surgical procedure in pregnancy or puerperium
- Dehydration
- Ovarian hyperstimulation syndrome
- Admission or immobility
- Systemic infection
- Long distance travel
Give an example of a cause of dehydration in pregnancy
Hyperemesis gravidum
What is the most common presentation of DVT?
Unilateral leg pain and swelling
What are the other clinical features of DVT?
- Pyrexia
- Pitting oedema
- Tenderness or prominent superficial veins
What is it important to note when considering the symptoms of DVT?
Some of the symptoms are normal in pregnancy
Where do the majority of DVTs form in pregnant women?
In the proximal veins
Which leg is more commonly affected by DVT in pregnant women?
Left
Why is the left leg more commonly affected by DVT in pregnant women?
Thought to be due to the compression effect of the uterus on the left iliac vein
What are the key clinical features of PE?
- Sudden onset dyspnoea
- Pleuritic chest pain
- Cough
- Haemoptysis
What signs might a patient with PE have?
- Tachycardia
- Tachypnoea
- Pyrexia
- Raised JVP
- Pleural rub
- Pleural effusion
What is it important to examine for in any patient with suspected PE?
DVT
What are the differential diagnoses for unilateral leg pain and swelling?
- Cellulitis
- Ruptured Baker’s cyst
- Superficial vein thrombosis
- Feature of normal pregnancy
Why is the differential diagnosis of PE difficult?
Because there are a large number of possible diagnoses for sudden onset dyspnoea and chest pain
What should be excluded in a patient presenting with sudden onset chest pain and dyspnoea?
- Acute coronary syndromes
- Aortic dissection
- Pneumonia
- Pneumothorax
What investigations should be performed in suspected DVT or PE?
- FBC
- U&Es
- LFTs
- Coagulation screen
Are investigations required before treatment is initiated in DVT or PE?
Yes
Is testing for D-dimers recommended when DVT/PE is suspected in pregnancy?
No
Why is it not recommended to test for D-dimer when DVT/PE occurs in pregnancy?
Because a rise in D-dimer is normal in pregnancy
What is the definitive investigation for suspected DVT?
Compression duplex ultrasound scan
What should be done if the compression duplex ultrasound scan is negative, but clinical suspicion for DVT is still high in pregnancy?
The test can be repeated 1 week later, whilst maintaining the patient on anti-coagulation
How should women presenting with PE be initially assessed?
With ECG and CXR
How is the definitive diagnosis of PE in pregnancy made?
CTPA or V/Q scan
What should pregnant women receiving a VQ scan be informed of?
It is associated with an increased risk of childhood cancer
What investigation should be performed if a woman presents with clinical features of DVT and PE?
Duplex ultrasound scan
Why should a duplex ultrasound scan be performed if a woman presents with features of DVT and PE?
Because if it is positive, a CTPA or VQ scan doesn’t need to be performed, and it saves the woman from unnecessary radiation exposure
How should all women with symptoms of VTE in pregnancy be managed?
They should receive LMWH, started immediately until diagnosis is excluded by definitive testing
How is the dose of LMWH for suspected VTE in pregnancy determined?
It should be titrated against the woman’s booing weight
How should pregnant women with confirmed VTE be managed after the acute event?
Anti-coagulation should be maintained throughout the pregnancy, until 6-12 weeks post-partum
What advice should pregnant women on anti-coagulation for confirmed DVT in pregnancy be given regarding delivery?
They should omit their dose 24 hours before any planned induction of labour or C-section. Furthermore, they should not take their dose if they think they are going into labour
What is the anticoagulant of choice for VTE in pregnancy in the UK?
LMWH
What are the alternatives to LMWH for VTE in pregnancy?
- Unfractionated heparin
- New oral anticoagulants (e.g. rivaroxiban)
Can warfarin be used for VTE in pregnancy?
No
Why can warfarin not be used in pregnancy?
Because it is teratogenic, and can lead to fetal loss through haemorrhage
What treatment should be considered when VTE occurs at term?
The use of IV unfractionated heparin
When should the use of IV unfractionated heparin be discontinued around delivery?
6 hours before planned induction of labour or C-section
What is the advantage of the use of IV unfractionated heparin at term compared to LMWH?
It is discontinued at 6 hours before delivery, rather than 24
When should pregnant women be assessed for risk of VTE?
Early in their pregnancy, and again in the intrapartum and postnatal periods
When should women be offered thromboprophylaxis in pregnancy?
If they have;
- 4 or more risk factors in first trimester
- 3 or more risk factors in second trimester
- 2 or more risk factors in post-partum period
How long should a woman receiving thromboprophylaxis antenatally continue anticoagulation for?
At least 6 weeks post-partum
Why should a woman receiving thromboprophylaxis continue for at least 6 weeks post-partum?
As the immediate post-natal period carries the highest risk
Should anticoagulation be given to women who have a C-section?
Yes, should be considered in all women who have had a C-section, particularly in emergency cases
What course of anticoagulation should be given to women who have had a C-section?
10-day course of LMWH
Who has a particularly high risk of developing a VTE in pregnancy?
- Women with previous VTE
- Known thrombophilia
Who should be involved in the management of woman at particularly high risk of VTE in pregnancy?
Haematologist
How should women who had previous VTE provoked from major surgery be managed in pregnancy?
Should have LMWH thromboprophylaxis from 28 weeks onwards
How should women with any other previous VTE be managed in pregnancy?
LMWH thromboprophylaxis throughout antenatal period
How should women with known antithrombin deficiency or antiphospholipid syndrome be managed in pregnancy?
Should have thromboprophylaxis with high dose LMWH, usually 50 or 75% of treatment dose, or full treatment dose
