VTE and PE in pregnancy Flashcards

1
Q

What % of women who develop VTE in pregnancy have an underlying thrombophilia?

A

50%

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2
Q

What % of PE in pregnancy are fatal?

A

15%

66% occur within 30 mins of embolic event.

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3
Q

Antenatal risk factors for VTE

A
  • AMA
  • Obesity
  • Hospitalisation
  • Varicose veins
  • Multiple pregnancy
  • Diabetes
  • Inflammatory bowel disease
  • Thrombophilia
  • UTI
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4
Q

Postnatal risk factors for VTE

A
  • AMA
  • Obesity
  • CS especially emCS
  • PPH
  • HTN and PET
  • Smoking
  • Medical comorbidities
  • Stillbirth
  • Postpartum infection
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5
Q

Outline the pathophysiology of why pregnancy has higher risk of VTE using Virchow’s triad

A

Venous stasis:

  • Increased venous capacitance
  • Compression of large veins by the gravid uterus.

Endothelial injury: delivery is associated with vascular injury and changes at the uteroplacental surface, which probably contribute to the increased risk of VTE in the immediate postpartum period.

Hypercoagulable state:

  • Increases in factors I, II, VII, VIII, IX, and X
  • Decrease in protein S
  • Increase in resistance to activated protein C
  • Increased activity of the fibrinolytic inhibitors PAI-1 and PAI-2 .
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6
Q

Discuss the utility of compression duplex ultrasound in DVT/PE diagnosis

A

Indication:

  • Suspected PE with DVT signs/sx
  • Suspected DVT

If confirms DVT, no further investigation for PE should be performed to limit radiation exposure. Commence tx.

If USS negative and low suspicion: stop anticoagulation.
If USS negative but high suspicion: stop anticoagulation but perform serial USS day 3 and day 7.

Sensitivity 95%
NPV 99.5%

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7
Q

What ECG changes are associated with PE?

A
  • TWI
  • S1Q3T3
  • RBBB
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8
Q

What the advantages and disadvantages of CTPA (cf. VQ scan)?

A

Advantages:

  • Quick and easily accessible.
  • Radiation dose to fetus low with shielding
  • NPV 99%
  • Can diagnose other pathology e.g. aortic dissection, pulmonary oedema, pneumonia
  • Can continue to breastfeed after

Disadvantages:

  • Radiation dose 20-100x more than VQ scan.
  • Increased risk of maternal breast cancer
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9
Q

What the advantages and disadvantages of V/Q scan (cf. CTPA)?

A

Advantages:

  • Lower radiation exposure to mum.
  • Better at diagnosing peripheral PE
  • Less prone to suboptimal image quality due to poor contrast filling of pulmonary vessels or respiratory motion artefact.
  • NPV 100%

Disadvantages:

  • Increased childhood cancers
  • Diagnostic accuracy compromised if CXR abnormal
  • Unable to breastfeed for 12 hours after.
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10
Q

What is the indication for peak anti Xa activity?

A
  • Extremes of bodyweight
  • Renal impairment
  • Recurrent VTE
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11
Q

When is platelet monitoring indicated?

A
  • Post-op and receiving unfractionated heparin.

Every 2-3 days until stopped.

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12
Q

In a massive PE, is clexane or unfractionated heparin preferred and why?

A

Unfractionated heparin preferred.
Rapid effect.
Easier to adjust if thrombolysis is administered.

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13
Q

How would you manage a woman usually on clexane in labour and elective delivery?

A
  • Advise to stop injecting clexane when labour starts.
  • If injected recently, monitor APTT; if abnormal may need protamine sulphate reversal.

Planned delivery:
- Stop clexane 24 hours prior to unfractionated heparin 6 hours prior to.

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14
Q

When is it safe to remove an epidural catheter?

A

At least 12 hours after last clexane dose.

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15
Q

When is it safe to administer epidural or spinal?

A

At least 24 hour after clexane or 6 hours after heparin.

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16
Q

Following regional anaesthesia, when is it safe to give clexane?

A

After at least 4 hours from spinal anaesthesia or epidural catheter removal.

17
Q

Is breastfeeding contraindicated with clexane and warfarin use?

A

No

18
Q

Outline follow-up plan after VTE diagnosis/tx

A
  • Obstetric medicine or haematology clinic
  • Thrombophilia testing to be considered
  • Post-thrombotic venous damage assessment
  • Future pregnancy counselling
19
Q

Why should warfarin not be used in pregnancy?

A

Crosses placenta.
Risk of: first trimester embryopathy; miscarriage, prematurity, low BW, neurodevelopmental issues, fetal and neonatal bleeding