VTE in Pregnancy: Understanding the Risk

VTE in Pregnancy:
Understanding the Risk
Dr Carol Lim
HoSHAS, Temerloh, Pahang
7 March 2014
“Blocked Drains” – VTE in Pregnancy Seminar 2014
Serena Williams – DVT  PE
Other famous faces who had VTE…
Zsa Zsa Gabor,
DVT in 2010
Placido Domingo,
Pulm Embolism in 2013
Hilary Clinton,
VTE in 2012
VTE in Asians?
• Not that uncommon
• Under-diagnosed, unsuspected
• Lack of awareness, ?does not believe (the eyes
do not see what the mind doesn’t know)
• Similar risk factors
• Expect rising incidence:
-obesity
-older age at child-bearing
-rising CS rates
-ART pregnancy
Thirucelvam Ayadurai, 2008
VTE
• VTE in 14-22% of gynaecological surgery pt without
prophylaxis (symptomatic & subclinical)
• Pulmonary embolism attributes to 10% of hospital
deaths
• Pulmonary embolism – most common preventable
cause of hospital death
VTE in Pregnancy
VTE incidence 1-2/1000 pregnancies
Pregnancy : 10x risk
Any stage of pregnancy
Highest during puerperium :
5x risk vs pregnancy
60x risk vs non-pregnant
Elective CS 2x risk vs Vaginal delivery
Emergency CS 2x risk vs Elective CS
Emergency CS 4x risk vs Vaginal delivery
RCOG Green-top Guideline No.37a, Nov 2009
UK : VTE MMR
 1% overall case fatality for VTE in pregnancy
VTE MMR:
UK 1.56/100K LB maternities (2003-2005);
0.79/100K maternities (2006-2008) (n= 18/155; 11.6%)
Some of the learning points:
• There is still poor awareness re VTE risk in
pregnancy
• Chest symptoms arising for the 1st time in at-risk
patients calls for investigation
• Pay attention to hydration esp in hyperemesis
gravidarum pt
Saving Mothers’ Lives, 2006-2008
Malaysia : VTE MMR
1.9/100K LB (2006) (n= 9/127; 7.1%)
1.5/100K LB (2007) (n= 7/136; 5.1%)
4.7/100K LB (2008) (n= 23/133; 17.3%)
• Mostly clinical diagnosis; <25% confirmed by PM
Examination
• Obstetric embolism* is the leading cause of
Maternal Death in 2008
Report on CEMD in Malaysia 2006-2008
* 40 cases of Obstetric embolism (AFE + blood clot embolism), ie 30%
Maternal Deaths in 2012: Phg vs Sbh
Pahang
Sabah
Total maternal deaths (n)
14
49
Total deliveries
24085
62476
MMR (per 100K LB)
58.1
78.4
MMR (minus Fortuitous)
45.8
54.4
MMR (minus PTI & fortuitous)
33.3
46.2
Obstetric blood clot embolism (n)
2
1
% Obstetric blood clot embolism
/Mat Death (minus Fortuitous)
18.2%
2.9%
Mortality rate of Obstetric Bld Clot Embolism
per 100K LB* (per 100K LB)
*Msia: 1.5/100K LB in 2007; Msia: 4.7/100K LB in2008;
*UK: 1.56/100K LB in 2003-2005; UK: 0.79/100K LB in 2006-2008
8.3
1.6
Maternal Deaths in 2013: Phg vs Sbh
Pahang Sabah
Total maternal deaths (n)
10
56
(1 BWN)
(36 BWN)
Pulm (blood clot) embolism (n) 1
0
Cerebral venous thrombosis*
2
0
Thrombotic Deaths
UK 2006-2008
Total 18 deaths (out of 155; 11.6%)
16 pulmonary embolism
2 cerebral vein thrombosis
Msia 2006-2008
Total 39 deaths (out of 396; 9.8%)
 All pulmonary embolism
VTE is less common than massive PPH, yet..
VTE
Incidence per 1000 pregnancies
(maternities)
M’sia 2008
number of mat deaths due to..
1-2
Massive
PPH
5-7
23
26
% of Indirect + Direct (133)
17.3%
19.5%
MMR per 100K LB
4.7
5.3
Pahang 2012
number of mat deaths due to..
2
1
MMR per 100K LB
8.3
4.2
HoSHAS 2004-2013
Total 35 maternal deaths in 10yr
7 pulmonary embolism deaths (20%)
5 obstetric hemorrhage deaths (14.3%)
Total deliveries in these 10yr = 70253
VTE MMR 9.96/100,000 LB
VTE in Obstetric Patients in HoSHAS
Total of 7 VTE from July 2013 – Feb 2014
Antenatal
presentation
Postnatal
presentation
Total
DVT
3
PE
1
Total
4
1
2
3
4
3
7
Reported incidence 1-2/1000 pregnancies
Virchow’s Triad
Compression of left iliac vein by
-gravid uterus,
-right iliac art
-left infundibulopelvic vessels
Immobilisation
Hormonally mediated dilatation
of vein
Vascular compression at delivery
Assisted / operative delivery
Hypercoagulobility in pregnancy
-increase clotting factors (VIII, IX, X)
& fibrinogen
-reduced levels of anti-coagulators
(protein S, antithrombin)
Modifications to Haemostasis by Pregnancy
• Hypercoagulability
in
pregnancy,
in
preparation for parturition.
1. Increased concentration of clotting factors
VIII, IX and X. Fibrinogen level increase by 50%
while fibrynolytic activity is decreased.
2. Levels in anticoagulators such as antithrombin
and protein S fall.
• These changes are observed from 1st trimester
to 6 weeks after delivery.
• Peak in coagulation in immediate postpartum
which tails off after 3 weeks postpartum.
Venous stasis exaggerated in pregnancy by:
1.Venous dilatation
2.Compression of the gravid uterus
on the IVC
3.Compression of the iliac vein by
left infundibulopelvic vessels
Endothelial injury
1.Vascular compression at
delivery
2.Assisted / operative delivery
Pathophysiology of thrombosis
• Thrombosis occurs when there is disruption of
Virchow’s triad.
• Modifications of haemostasis by pregnancy renders
blood hypercoagulable.
• Hyperemesis and pre-eclampsia further contribute
to thrombogenesis.
• Excessive fluid loss in hyperemesis concentrates
blood and the resultant bed rest further promotes
stasis of blood flow.
Pregnancy…..
….an independent risk factor for VTE
Risk Assessment –Very High Risk
VERY HIGH RISK
• Recurrent VTE associated with either antithrombin
deficiency or antiphospholipid syndrome, who will often be
on long-term oral anticoagulation
 Require higher dose of LMWH (high prophylactic 12-hourly
or 75% of treatment dose)
 Antenatal + 6 weeks postnatal or until conversion to
warfarin
Risk Assessment – High Risk
High Risk
• Original VTE was unprovoked, idiopathic or
estrogen-related;
• Has other risk factors eg family (1st degree relatives)
history of VTE
• Thrombophilia
Antenatal + 6w Postnatal thromboprophylaxis
Risk Assessment –Intermediate Risk
Intermediate Risk
• Original VTE provoked by transient major risk factor
(& no longer present) and does not have other risk
factor
Surveillance for development of other risk factor
6w Postnatal thromboprophylaxis
Consider antenatal thrombophylaxis
High Risk:
ANTENATAL
POSTNATAL
• Single VTE with thrombophilia • Any previous VTE
(or family history), or
• Was on antenatal
unprovoked / estrogen-related
thromboprophylaxis
• Previous recurrent VTE (>1
episode)
 Antenatal + 6w postnatal
thromboprophylaxis
 6w postnatal
thromboprophylaxis
Intermediate Risk
ANTENATAL
• Single previous VTE with no
family history or
thrombophilia
• Thrombophilia but no VTE
• Has medical co-morbidities
• Intravenous drug user
• Surgical procedure
POSTNATAL
• Emergency LSCS
• Asymptomatic thrombophilia
(inherited or acquired)
• BMI >40kg/m2
• Prolonged hospital admission
• Medical co-morbidities
 Consider antenatal + 6 weeks  At least 7days of postnatal
postnatal thromboprophylaxis
thromboprophylaxis
 Longer if risk persists or >3
risk
Low Risk
ANTENATAL
• Categorised according to
number of risk factors
a) If >3 risk factors 
Intermediate Risk
b)If >2 risk factors AND
admitted 
Intermediate Risk
c) If <3 risk factors 
Lower Risk
POSTNATAL
• Categorised according to
number of risk
a) If >2 risk factors 
Intermediate Risk
b) If <2 risk factors  Lower
Risk
 Advice mobilisation &
adequate hydration
 Advice mobilisation &
adequate hydration
Risk Factors
•
•
•
•
•
•
•
Age >35yr
BMI >30kb/m2
Parity >3
Smoker
Gross varicose veins
Current systemic infection
Immobility including long
distance travel
• Pre-eclampsia
• Dehydration/ hyperemsis/
OHSS
• Multiple pregnancy/ ART
Additional postnatal risk factors:
• Elective CS
• Mid-cavity rotational oerative
delivery
• Any surgical procedure in
puerperium
• Prolonged labour (>24hr)
• PPH >1L or requiring blood
transfusion
The other sort of risks – of pt on
antenatal thromboprophylaxis…
•
•
•
•
•
Medication error (wrong dosage)
Hematoma / bruising
Sharp injuries
Safe disposal of needle
Beware of pt started on antenatal anticoagulation – prophylaxis or treatment
Risk of bleeding – if goes into labour or suffer
miscarriage
Change in Practice
•
•
•
•
Offer UH & LMWH, pt’s choice of medication
SOPs refined
Checklist / risk factors in smart phone
Enquire re DVT / Pulm Embolism during postnatal
ward rounds
• Involve primary care / community level
• Contraceptive – must be addressed too; Implanon
offered
 VTE is Preventable!
Summary
• Pregnancy itself is a risk for VTE
• CS; puerperium – higher risk
• All obstetric unit must have SOP for
thromboprophylaxis
• All women (antenatal & postnatal) must be
assessed for VTE risk, at booking, every
admission, at delivery
• All assessment must be documented
• On going training to increase awareness
• Beware of pt on antenatal anti-coagulation
What
Why
When
Where
Who
How
Pregnancy is a risk for VTE
Virchow’s Triad fulfilled
Postnatal & Antenatal
Pulmonary Embolism, DVT,
Cerebral Vein Thrombosis
Elderly, Obese, ↑CS rate, ↑ART
pregnancy
SOPs, assess for risk, training,
create awareness, daily practice
… don’t forget about Family
Planning!
….. and one of us survived DVT+ massive
bilateral PE
(among the not-so-famous faces)
(NOT the one with raised hand …..)
Thank you
[email protected]

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