VTE in pregnancy GT37a, b Flashcards

1
Q

How many DVTs in pregnancy occur on the left?

A

90%

60 when not pregnant

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2
Q

How many DVTs arise in the ileo-femoral veins?

A

70%

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3
Q

How many with a clinical diagnosis go on to have a proven DVT?

A

8%

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4
Q

How many proven DVT patients will have a PE?

A

5%

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5
Q

How much more likely to develop DVT if previous VTE?

A

25 times

Recurrence rate 2-11% in pregnancy

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6
Q

What is the advice if there is a strong clinical suspicion but a negative scan?

A

Repeat 3/7

MRV if still suspicious

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7
Q

Which LFT is affected by tinzaparin?

A

ALT

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8
Q

How many will have a skin allergy to LMWH within 60 days?

A

2%

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9
Q

How does LMWH work?

A

Potentiates antithrombin III which inhibits conversion of X to Xa

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10
Q

What is the advice around delivery for those on antenatal treatment dose LMWH?

A

IOL when favourable or 40/40 - consider prophylactic dose if unfavourable on day IOL
24 hours from dose before regional anaesthetic
Prophylactic dose 1-2 days following VB and 2-3 days following CS
Protamine if labours within 3 hrs of LMWH dose

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11
Q

How much does CS increase the risk of a PE?

A

5 times

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12
Q

How much does VQ scan increase the risk of childhood cancer?

A

1:1000,000 background to 1:280,000

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13
Q

How much does CTPA increase breast cancer risk?

A

14%

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14
Q

How much does antithrombin deficiency increase risk of VTE?

A

10 times - 50% of untreated patients will have a VTE

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15
Q

What % of patients with pregnancy related VTE will have an underlying thrombophilia?

A

50%

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16
Q

How many of general population have factor V leiden deficiency?

What is the risk of VTE in pregnancy?

A

5%

1:100 (1:1000 when not pregnant)

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17
Q

What is the risk of devloping a VTE in subsequent pregnancies?

A

10%

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18
Q

How should anti-Xa levels be measured?

A

A test that does not use exogenous antithrombin, aim for 4 hour peak levels of 0.5-1.0iu/ml

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19
Q

What is the advice for women who are taking warfarin antenatallly and fall pregnant?

A

Stop and change to LMWH as soon as pregnancy confirmed, ideally within 2/52 of missed period and by 6/40

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20
Q

Which women with prior VTE require thrombophilia testing?

A

Only if result will influence Rx - antithrombin/APS may alter dose of LMWH

FHx VTE with antithrombin deficiency or thrombophilia not detected
Unprovoked VTE - test for APL antibodies

Consider if no personal hx but FHx of unprovoked/oestrogen dependent VTE in 1st degree relative <50

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21
Q

How long after prophylactic/therapeutic LMWH should regional anaesthetic be avoided?

A

Prophylactic - 12 hours

Therapeutic - 24 hours

22
Q

How often should platelets be checked if unfractionated heparin is used?

A

Every 2-3 days from days 4-14 or until heparin is stopped

23
Q

What is the recommended calf pressure of graduated compression stockings?

A

14-15mmHg

24
Q

What was the mortality rate from VTE in 2006-2008?
What % were BMI >30?

How many had identifiable risk factors?

A

0.70/100,000 maternities
60% obese

Risk factors in 89%

25
Q

What is the incidence of antenatal PE according to UKOSS?

A

1.3/10,000 maternities

26
Q

What is the absolute risk/incidence of VTE in pregnancy and the puerperium? When does it peak postpartum?
And the relative risk?

A

Incidence 1-2/1000
Peaks week 3
RR 4-6x

27
Q

What % of pregnancy-related VTE are due to heritable thrombophilia?

A

20-50%

28
Q

By how much is VTE risk increased by admission to hospital?

A

x18

29
Q

At what level of creatinine clearance does LMWH need to be adjusted?

A

<30ml/min for enoxaparin and dalteparin

<20ml/min for tinzaparin

30
Q

What are the features of warfarin embryopathy and how many fetuses are affected at 6-12/40 exposure?

A
Hypoplasia of nasal bridge
Congenital heart defects
Ventriculomegaly
Agenesis of corpus callosum
Stippled epiphyses
5%
31
Q

What are the ‘high’ risk factors for VTE and what is the LMWH regime?

A

Any previous VTE except a single event related to major surgery
Anyone requiring antenatal LMWH
High risk thrombophilia
Low risk thrombophilia + FHx

LMWH as early as possible
6/52 postnatally

32
Q

What are the high risk thrombophilias?

A

Antithrombin deficiency
Protein C or S deficiency
Compound/homozygous for low risk thrombophilias
APS with previous VTE

33
Q

What are the low risk thrombophilias?

A

Heterozygous for Factor V Leiden or prothrombin G20210A mutations

34
Q

What are the ‘intermediate’ antenatal risk factors for VTE and what is the management?

A

Hospital admission
Single previous VTE related to major surgery
High risk thrombophilia + no VTE
Medical comorbidities
Any surgical procedure e.g. appendicectomy
OHSS (T1 only)

Consider antenatal LMWH

35
Q

What are the ‘intermediate’ postnatal risk factors for VTE and what is the management?

A
Caesarean section in labour
BMI >= 40
Readmission/prolonged PP admission (>3/7)
Surgical procedure in the puerperium
Medical comorbidities
>= 2 or more moderate risk factors

LMWH for 10/7; consider extending to 6/52 if persisting or >=3 moderate risk factors

36
Q

What are the moderate risk factors antenatally for VTE and what is the management?

A
BMI >30
Age >35
Para >=3
Smoker
Gross varicose veins
Current pre-eclampsia
Immobility
FHx unprovoked/oestrogen VTE in 1st deg relative
Low risk thrombophilia
Multiple pregnancy
ART/IVF
Transient: Dehydration/HG, systemic infection, travel >4hrs

> = 4 - prophylaxis from T1
3 RFs - from 28/40

37
Q

What are the moderate postnatal risk factors for VTE and what is the management?

A
BMI >30
Age >35
Para >=3
Smoker
Elective CS
Gross varicose veins
Current pre-eclampsia
Immobility incl long distance travel
FHx VTE
Low risk thrombophilia
Multiple pregnancy
Systemic infection
Prem delivery
SB this pregnancy
Midcavity rotational operative delivery
Labour >24 hours
PPH >1L or blood transfusion

> = 2 risk factors - treat as intermediate risk

38
Q

What are the top 5 increased risk factors for VTE (by OR)?

A
Heart disease - PE (aOR 43.4)
Previous VTE (24.8)
Immobility PN (10.8)
Obstetric haemorrhage (9)
SLE (8.7)
39
Q

What is the management of a highly clinically suspicious DVT but negative on compression duplex ultrasound?

A

Discontinue anticoagulation treatment

Repeat USS on day 3 and 7

40
Q

When should a temporary IVC filter be used?

A

When there is an iliac vein VTE or patients with proven DVT and recurrent PE despite adequate anticoagulation

41
Q

What is the maintenance treatment for VTE?

A

Throughout remainder of the pregnancy and 6/52 postnatal, until 3/12 total treatment

42
Q

What is the delay for giving LMWH following spinal/epidural catheter removal?

A

4 hours

Catheter should not be removed within 12 hours of most recent injection

43
Q

How long should postpartum warfarin be avoided in women at high risk of PPH?

A

5 days

44
Q

What is the relative risk of VTE in the puerperium?

A

20x

45
Q

How many patients will develop a PE with untreated DVT?

A

15-24%

46
Q

What % of women on peripartum anticoagulation develop wound haematoma?

A

9%

47
Q

What is the prevalence of post-thrombotic syndrome following DVT in pregnancy?
What is the guidance re: anti embolism stockings?

A

42%

>23mmHg worn for 2 years

48
Q

what thromboprophylaxis for 29yr, pri, heterozygous for FV leiden

A

prophylactic LMWH for 10/7 p/n

49
Q

what thromboprophylaxis for 24yr old pri, no Hx of VTE but homozygous for FV Leiden?

A

prophylactic LMWH antenatally and 6/52 p/n

50
Q

what thromboprophylaxis for 28 yr old multi, BMI=42, no other RF

A

prophylactic LMWH for 10/7 post natal

51
Q

32 yr old, multip, DVT in previous pregnancy, no other RF

A

prophylactic LMWH antenatally and 6/52 p/n

52
Q

27yr old pri, has antiphospholipid syndrome, previous PE

A

high dose LMWH antenatally and 6/52 p/n plus long term anticoagulation