VTE Pregnancy Flashcards
Physiological changes in pregnancy with coagulable state
Physiological hypercoagulable state
Increase in factor 8,9,10
Fibrinogen rises by 50%
Decreased fibrinolytic activity
Endogenous anticoagulants like protein S and antithrombin fall
This risk is present from the T1 and to 12 weeks post partum
APTT is normal
Vasodilation in the lower limbs, Decreased flow L>R due to compression of the L iliac vein by the R iliac artery + ovarian artery
What is the highest direct cause of maternal mortality in the UK
PE
Kills 5-10 woman/ year
When is the greatest risk for VTE
Post partum
How much is the risk of VTE increased compared to the general population
6X increased risk
This is doubles if you have an ElLSCS
EMLSCS doubles the risk compared to an ELLSCS
What is the actual risk of VTE after a caesarean?
1-2%
Which leg
90% L side
increased risk venous stasis
iliofemoral is much more common then in the non pregnant patient
clinical assessment for VTE
Not reliable
clinical judgement will be wrong in 30-50% of cases in pregnancy
oedema and leg pain are common in pregnancy without VTE
What are the exam signs of PE
Tachycardia Tachypnoea Raised JVP Loud second heart sound R ventricular heave
If there is pulmonary infarction a fever and pleural rub may be present
Risk factors for VTE
Thombophilia Heritable Anti thombin deficiency Protein C or S deficinecy Factor V leiden Prothrombin gene G20210A
Acquired
Anti phospholipid syndrome
Persistent high antibodies
medical comorbidities: Cancer, HF, SLE, IBD/joint disease nephrotic syndrome, T1DM with nephropathy, sickle cell disease, IVDU Age over 35 P3 BMI over 30 Gross varicose veins Paraplegia
Pregnancy related Multiple pregnancy Current PET LSCS Prolonged labour Midcavity rotational operative delivery still birth preterm birth PPJ over 1 L or requiring transfusion
Transient factors Hyperemesis and dehyration Surgical procedure in pregnancy Overian hyperstimulation Admission / immobility Systemic infection req antibiotics or admission Long distance travel - over 4 hours
What investigations are needed for the diagnosis of an acute DVT?
Compression duplex ultrasound should be undertaken where there is clinical suspicion of DVT.
If ultrasound is negative and there is a low level of clinical suspicion, anticoagulant treatment can
be discontinued. If ultrasound is negative and a high level of clinical suspicion exists, anticoagulant
treatment should be discontinued but the ultrasound should be repeated on days 3 and 7.
What investigations are needed for the diagnosis of an acute pulmonary embolism (PE)?
What does the ECG show?
What does the CXR show?
Women presenting with symptoms and signs of an acute PE should have an electrocardiogram
(ECG) and a chest X-ray (CXR) performed.
ECG R axis deviation RBBB Peaked T waves in lead 2 S1Q3T3 can be normal in pregnancy - not reliable CXR - areas of translucency in underperfused lung Atelectasis Wedge shaped infarction Pleural effusion
What if sx of PE and DVT - what test?
In women with suspected PE who also have symptoms and signs of DVT, compression duplex
ultrasound should be performed. If compression ultrasonography confirms the presence of DVT,
no further investigation is necessary and treatment for VTE should continue.
In women with suspected PE without symptoms and signs of DVT, a ventilation/perfusion (V/Q) lung
scan or a computerised tomography pulmonary angiogram (CTPA) should be performed.
If the CXR is abnormal - what Ix is best next in PE work up ?
When the chest X-ray is abnormal and there is a clinical suspicion of PE, CTPA should be performed
in preference to a V/Q scan.
Compare and contract CTPA with VQ scanning
Women with suspected PE should be advised that, compared with CTPA, V/Q scanning may carry
a slightly increased risk of childhood cancer but is associated with a lower risk of maternal breast cancer; in both situations, the absolute risk is very small.
Where feasible, women should be involved in the decision to undergo CTPA or V/Q scanning.
Ideally, informed consent should be obtained before these tests are undertaken.
What baseline blood investigations should be performed before initiating anticoagulant therapy?
Before anticoagulant therapy is commenced, blood should be taken for a full blood count,
coagulation screen, urea and electrolytes, and liver function tests.
Performing a thrombophilia screen prior to therapy is not recommended.
What is the initial treatment of VTE in pregnancy?
In clinically suspected DVT or PE, treatment with low-molecular-weight heparin (LMWH) should be
commenced immediately until the diagnosis is excluded by objective testing, unless treatment is
strongly contraindicated.
LMWH should be given in doses titrated against the woman’s booking or early pregnancy weight.
There is insufficient evidence to recommend whether the dose of LMWH should be given once daily or in two divided doses.
There should be clear local guidelines for the dosage of LMWH to be used.
How do monitor heparin levels?
Routine measurement of peak anti-Xa activity for patients on LMWH for treatment of acute VTE in pregnancy or postpartum is not recommended except in women at extremes of body weight
(less than 50 kg and 90 kg or more) or with other complicating factors (for example, with renal
impairment or recurrent VTE).
Routine platelet count monitoring should not be carried out.
How should massive life-threatening PE in pregnancy and the puerperium be managed?
Collapsed, shocked women who are pregnant or in the puerperium should be assessed by a team
of experienced clinicians including the on-call consultant obstetrician.
Women should be managed on an individual basis regarding: intravenous unfractionated heparin,
thrombolytic therapy or thoracotomy and surgical embolectomy.
Intravenous unfractionated heparin is the preferred, initial treatment in massive PE with cardiovascular compromise.
The on-call medical team should be contacted immediately.
An urgent portable echocardiogram or
CTPA within 1 hour of presentation should be arranged. If massive PE is confirmed, or in extreme circumstances prior to confirmation, immediate thrombolysis should be considered.
Should graduated elastic compression stockings be employed in the acute management of VTE in pregnancy?
In the initial management of DVT, the leg should be elevated and a graduated elastic compression
stocking applied to reduce oedema. Mobilisation with graduated elastic compression stockings
should be encouraged
What is the role of inferior vena cava filters in the management of VTE in pregnancy?
Consideration should be given to the use of a temporary inferior vena cava filter in the peripartum
period for patients with iliac vein VTE to reduce the risk of PE or in patients with proven DVT and
who have recurrent PE despite adequate anticoagulation.
What is the maintenance treatment of DVT or PE?
Treatment with therapeutic doses of subcutaneous LMWH should be employed during the remainder
of the pregnancy and for at least 6 weeks postnatally and until at least 3 months of treatment has
been given in total.
Women should be taught to self-inject LMWH and arrangements made to allow safe disposal of
needles and syringes. Outpatient follow-up should include clinical assessment and advice with
monitoring of blood platelets and peak anti-Xa levels if appropriate
Should anticoagulant therapy be altered during labour and delivery?
The woman on LMWH for maintenance therapy should be advised that once she is in established
labour or thinks that she is in labour, she should not inject any further heparin.
Where delivery is planned, either by elective caesarean section or induction of labour, LMWH
maintenance therapy should be discontinued 24 hours prior to planned delivery.
Regional anaesthetic or analgesic techniques should not be undertaken until at least 24 hours
after the last dose of therapeutic LMWH.
LMWH should not be given for 4 hours after the use of spinal anaesthesia or after the epidural
catheter has been removed, and the epidural catheter should not be removed within 12 hours of the most recent injection.
Are specific surgical measures required for anticoagulated patients undergoing delivery by caesarean
section?
In patients receiving therapeutic doses of LMWH, wound drains (abdominal and rectus sheath)
should be considered at caesarean section and the skin incision should be closed with interrupted
sutures to allow drainage of any haematoma.
What anticoagulant therapy should be employed in women at high risk of haemorrhage?
Any woman who is considered to be at high risk of haemorrhage, and in whom continued heparin
treatment is considered essential, should be managed with intravenous unfractionated heparin
until the risk factors for haemorrhage have resolved.
How should anticoagulation be managed postnatally?
Therapeutic anticoagulant therapy should be continued for the duration of the pregnancy and for at
least 6 weeks postnatally and until at least 3 months of treatment has been given in total. Before
discontinuing treatment the continuing risk of thrombosis should be assessed.
Women should be offered a choice of LMWH or oral anticoagulant for postnatal therapy after discussion about the need for regular blood tests for monitoring of warfarin, particularly during the first 10 days of treatment.
Postpartum warfarin should be avoided until at least the fifth day and for longer in women at
increased risk of postpartum haemorrhage.
Both ok for breast feeding
What measures can be employed to prevent the development of post-thrombotic syndrome?
Women should be advised that prolonged use of LMWH (more than 12 weeks) is associated with a significantly lower chance of developing post-thrombotic syndrome
Following a DVT, graduated elastic compression stockings should be worn on the affected leg to reduce pain and swelling. Clinicians should be aware that the role of compression stockings in the
prevention of post-thrombotic syndrome is unclear
What is post thrombotic syndrome and what increases its risk ?
What is the rate?
A chronic persistent leg swelling, pain,
a feeling of heaviness, dependant cyanosis, telangiectasis, chronic pigmentation, eczema,
associated varicose veins and in the most severe cases, venous ulceration. A case–control
study from Norway found a prevalence of PTS of 42% following DVT in pregnancy; proximal
postnatal thrombosis, smoking and age greater than 33 years were independent predictors of
the development of PTS
When to assess the risk:
All women should undergo a documented assessment of risk factors for VTE in early pregnancy
or prepregnancy.
Risk assessment should be repeated if the woman is admitted to hospital for any reason or develops
other intercurrent problems
Risk assessment should be repeated again intrapartum or immediately postpartum.
How to manage multiple risk factors?
4 or more should be considered for prophylactic low-molecular-weight
heparin (LMWH) throughout the antenatal period and will usually require prophylactic LMWH for 6/52 PN (with PN risk assessment)
3 current risk factors = prophylactic LMWH from 28 weeks and usually required for 6 weeks PN (with PN risk assessment)
2 current RF = LMWH for 10 days post partum
How should women with previous VTE be managed in pregnancy?
Prepregnancy counselling and a prospective
management plan.
Those who become pregnant before receiving such counselling should be referred at the earliest opportunity
Women with previous VTE (except those with a single previous VTE related to major surgery and no other risk factors) should be offered thromboprophylaxis with LMWH throughout the antenatal period
Women with previous VTE should have a careful history documented. Where objective documentation is not available, the previous diagnosis of VTE can be assumed in cases where the woman gives a good history and received prolonged (greater than 6 weeks) therapeutic
anticoagulation.
How to manage Heritable thrombophilia in pregnancy
with previous VTE
Women with previous VTE associated with antithrombin deficiency (who will often be on long-term oral anticoagulation) should be offered thromboprophylaxis with higher dose LMWH (either 50%, 75% or full treatment dose) antenatally and for 6 weeks postpartum or until returned to oral anticoagulant therapy after delivery.
MDT approach
Consideration given to antenatal anti-Xa monitoring +/- antithrombin replacement at initiation of labour or prior to caesarean section
If anti-Xa levels are measured, a test that does not use exogenous antithrombin should be used and 4-hour peak levels of 0.5–1.0 iu/ml aimed for
Other heritable thrombophilic defects are lower risk and can be managed with standard doses of thromboprophylaxis
How to manage Women with VTE associated with the antiphospholipid syndrome
should be offered thromboprophylaxis with higher dose LMWH (either
50%, 75% or full treatment dose) (see Appendix IV) antenatally and for 6 weeks postpartum or until
returned to oral anticoagulant therapy after delivery
Pregnant women with APS and prior VTE or arterial thromboses should be managed in collaboration
with a haematologist and/or rheumatologist with expertise in this area.
What extra advice is needed for women with previous recurrent VTE?
Advice regarding doses of LMWH in pregnancy should be sought from a clinician with expertise in
haemostasis and pregnancy
Some women with previous recurrent VTE require higher doses of LMWH
Women not on warfarin or other oral anticoagulants should be advised to start LMWH as soon as they have a positive pregnancy test
How to manage woman on long term warfarin?
Women on long-term warfarin or other oral anticoagulants should be counselled about the risks of these agents to the fetus and advised to stop their oral anticoagulant therapy and change to LMWH as soon as pregnancy is confirmed, ideally within 2 weeks of the missed period
and before the sixth week of pregnancy.
Previous VTE:
summary of how to stratify risk
Who gets high dose / treatment dose
WHo gets prophylaxis throughout
Who can start at 28 weeks?
Highest risk: Women with VTE + + antithrombin deficiency
+ APS
+ with recurrent VTE
(who will often be on long-term oral anticoagulation)
= higher dose LMWH (either 50%, 75% or full treatment dose antenatally and for 6/52 PP OR until on oral anticoagulant again
Manage MDT - haematologists
Medium risk
original VTE was unprovoked/idiopathic or related to OCP or related to a transient risk factor (other than major surgery) or who have
other risk factors
LMWH throughout the antenatal period.
Lower risk
In women in whom the original VTE was provoked by major surgery from which they have recovered and who have no other risk factors, thromboprophylaxis with LMWH can be withheld antenatally until 28 weeks provided no additional risk factors are present (in which case they should be offered
LMWH). They require close surveillance for the development of other risk factors.
Which women with prior VTE require thrombophilia testing?
Anyone on it antenatally
Previous VTE
thrombophilia
Anti Phospholipid
Prior to testing for thrombophilia, women should be counselled regarding the implications for
themselves and family members of a positive or negative result. The results should be interpreted
by clinicians with specific expertise in the area.
Women with a family history of VTE and either antithrombin deficiency or where the specific
thrombophilia has not been detected should be tested for antithrombin deficiency.
Women with an unprovoked VTE should be tested for the presence of antiphospholipid antibodies
Post natal prophylaxis
BMI over 40 – should have 10/7 LMWH
2 or more risk factors should have 10/7 LMWH
EMLSCS 10/7 LWMH
ELLSCS +1 RF = 10/7 LWMH
Additional risks = 6/52
Wound infection
surgery
Prolonged admission
Intrapartum management of LMWH
If any bleeding or labour – stop clexane
Reginal anaesthetic should wait 12 hours after prophylactic dose
Should not be given until 4 hours after a spinal or catheter removal
The catheter should not be removed within 12 hours of an injection
Early pregnancy risks for VTE and how to reduce them
OHSS - clexane throughout T1
Hyperemesis + admission = clexane until hyperemesis resolves
IVF is a risk factor to add in
