2015 37a VTE Risk Reduction

Question 1

When should VTE risk assessment be undertaken?

Answer 1

1. Prepregnancy
2. Early pregnancy
3. Hospital admission
4. Intrapartum
5. Postpartum

Question 2

Which women should be given LMWH throughout pregnancy & then 6 weeks postnatally?

Answer 2

4+ risk factors
Previous VTE unprovoked by major surgery

Question 3

Which women should receive LMWH from 28 weeks to 6 weeks PN?

Answer 3

3 risk factors

Question 4

Which women should receive LMWH for 10 days postpartum?

Answer 4

2 risk factors

Question 5

What are the antenatal risk factors for VTE?

Answer 5

1. BMI > 30
2. Age > 35
3. Parity ≥ 3
4. Smoker
5. Gross varicose veins
6. Current PET
7. Immobility eg paraplegia, PGP
8. Family hx VTE
9. Low-risk thrombophilia
10. Multiple pregnancy
11. IVF/ART

Question 6

What are the transient risk factors for VTE?

Answer 6

1. Dehydration
2. Hyperemesis
3. Current systemic infection
4. Long-distance travel

Question 7

What are the intermediate risk factors for which LMWH is considered in pregnancy?

Answer 7

1. Hospital admission
2. Single previous provoked VTE
3. High-risk thrombophilia, no VTE
4. Medical comorbidities
5. Surgical procedure
6. OHSS

Question 8

For which medical comorbidities is LMWH considered?

Answer 8

1. Cancer
2. Heart failure
3. Active SLE
4. Inflammatory bowel disease
5. Inflammatory polyarthropathy
6. Nephrotic syndrome
7. Type 1 DM with nephropathy
8. Sickle cell disease
9. Current IVDU

Question 9

Which women need 6 weeks postnatal LMWH?

Answer 9

1. Anyone requiring antenatal LMWH
2. Any previous VTE
3. High-risk thrombophilia
4. Low-risk thrombophilia + FHx

Question 10

What are the intermediate risk factors needing 10 days postnatal LMWH?

Answer 10

1. CS in labour
2. BMI ≥ 40
3. Readmission or prolonged PN admission
4. Surgical procedure in puerperium other than immediate perineal repair
5. Medical comorbidities

Question 11

What additional postnatal risk factors score for VTE risk?

Answer 11

1. Elective CS
2. Current systemic infection
3. Preterm delivery < 37+0
4. Stillbirth
5. Mid-cavity rotational or OVB
6. Prolonged labour > 24 hours
7. PPH > 1L or blood transfusion

Question 12

Which heritable thrombophilia needs a higher dose of LMWH & how is this managed?

Answer 12

Antithrombin deficiency
50%, 75% or full treatment dose
In collaboration with haematologist
Consider anti-Xa monitoring, aim 4-hour peak level 0.5-1.0 units/ml
Consider antithrombin replacement

Question 13

Which acquired thrombophilia needs a higher dose of LMWH, and how much?

Answer 13

Antiphospholipid syndrome
50%, 75% or full treatment dose

Question 14

Which asymptomatic heritable thrombophilias should be referred to a local expert, be considered for antenatal LMWH & given 6 weeks PN?

Answer 14

1. Protein C deficiency
2. Protein S deficiency
3. Homozygous factor V Leiden
4. Homozygous prothrombin gene mutation
5. Compound heterozygotes

Question 15

How should LMWH be managed at delivery?

Answer 15

1. Stop if any PVB
2. Avoid RA for > 12 hours after dose, or 24 for therapeutic dose
3. Avoid LMWH for > 4 hours after spinal
4. Stop day before elective CS

Question 16

What risk factors for haemorrhage may indicate TEDS or UFH over LMWH?

Answer 16

1. Major APH
2. Coagulopathy
3. Progressive wound haematoma
4. Suspected intra-abdominal bleed
5. PPH

Question 17

If women on warfarin are converted to LMWH in pregnancy, how is the conversion back managed?

Answer 17

5-7 days after delivery
With bridging

Question 18

What is the calf pressure of TEDS?

Answer 18

14-15mmHg

Question 19

By how much does LMWH reduce VTE risk?

Answer 19

60-70%

Question 20

What is the UK incidence of PE?

Answer 20

1.3 in 10,000

Question 21

What is the UK incidence of VTE in pregnancy & the puerperium?

Answer 21

1-2 in 1000

Question 22

What are the benefits of LMWH over UFH?

Answer 22

1. Just as effective
2. Risk of heparin-induced thrombocytopenia much lower
3. Lower risk of osteoporosis & fractures

Question 23

What are the benefits of UFH over LMWH?

Answer 23

1. Shorter half-life
2. More complete reversal of activity by protamine sulphate

Question 24

What is the dosing regime for enoxaparin?

Answer 24

< 50 kg 20mg OD
50-90kg 40mg OD
91-130kg 60mg OD
131-170kg 80mg OD
>170kg 0.6 mg/kg/d

Question 25

What is the dosing regime for dalteparin?

Answer 25

< 50 kg 2500 units OD
50-90kg 5000 units OD
91-130kg 7500 units OD
131-170kg 10,000 units OD
>170kg 75 units/kg/d

Question 26

What is the dosing regime of tinzaparin?

Answer 26

75 units/kg/day
< 50 kg 3500 units
50-90kg 4500 units
91-130kg 7500 units
131-170kg 9000 units
>170kg 75 units/kg/d

Question 27

What are the characteristics of warfarin embryopathy?

Answer 27

1. Hypoplasia of nasal bridge
2. Congenital heart defects
3. Ventriculomegaly
4. Agenesis of corpus callosum
5. Stippled epiphyses

Question 28

What proportion of fetuses exposed to warfarin between 6 & 12 weeks of gestation develop warfarin embryopathy?

Answer 28

Approx 5%

Question 29

What are the contraindications/cautions to LMWH use?

Answer 29

1. Known bleeding disorders
2. Active AN or PN bleeding
3. Increased risk major bleed eg placenta praevia
4. Thrombocytopenia < 75
5. Acute stroke in previous 4 weeks
6. Severe renal disease
7. Severe liver disease
8. Uncontrolled HTN, > 200/120