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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 4, July/August 2021
228
AFRICA
Prosthetic heart valve thrombosis in pregnancy:
a case series on acute management
S Foolchand, H Ramnarain
Abstract
Rheumatic heart disease is one of the leading causes of
valve dysfunction, resulting in prosthetic valve implantation.
Changes in physiology and the haemodynamics of pregnancy
increase the susceptibility of thrombosis to the prosthetic
valve in the pregnant woman. Valve redo surgery carries a
considerable risk of maternal and perinatal morbidity and
mortality. Women of reproductive age should be well coun-
selled regarding compliance with anticoagulation, contracep-
tion and pre-pregnancy planning.
Keywords:
thrombosis, prosthetic valves, pregnancy, cardiac
surgery, cardiopulmonary bypass pregnancy
Submitted 28/2/21, accepted 21/3/21
Published online 4/5/21
Cardiovasc J Afr
2021;
32
: 228–232
www.cvja.co.zaDOI: 10.5830/CVJA-2021-013
Cardiovascular disease (CVD) is one of the leading causes of
morbidity and mortality worldwide,
1
and remains one of the top
five causes of maternal death in South Africa.
2
Cardiac disease
accounted for 34.3% of maternal deaths in the sub-category
of medical and surgical conditions as a cause of maternal
mortality in the Sixth Triennial report.
2
The burden of rheumatic
heart disease and its sequelae contribute to a large proportion
of women presenting with CVD in low- and middle-income
countries (LMIC) such as South Africa.
1
The increased risk of
heart failure secondary to valve degeneration may be abrogated
by valve-replacement surgery,
1
resulting in amarked improvement
of an individual’s quality of life as well as life expectancy.
3
Mechanical and biological prosthetic (bio) heart valves are
used in replacement surgery depending on clinical presentation,
preference of the patient and availability of the various types
of prosthetic valves.
3
However, bio prosthetic valves often result
in re-operation due to dysfunction, especially when implanted
in younger patients.
3
Mechanical valve prostheses are more
commonly used in South Africa. These operations are generally
performed on younger women in the reproductive age group and
the implications of surgery and especially the use of warfarin (an
oral anticoagulant) and its potential problems associated with
pregnancy are often poorly understood.
The use of warfarin is lifelong, which poses the risk of
teratogenicity in pregnancy, particularly in the first trimester, and
foetal wastage later in the pregnancy.
3,4
The use of unfractionated
heparin is associated with adverse effects on the mother.
4
Reports
also include the risk of postpartum haemorrhage at delivery in
patients who have been anticoagulated.
5
Cardiac surgical intervention in pregnancy historically carries
a greater risk to both mother and foetus. A recent meta-analysis,
assessing maternal and foetal outcomes after cardiac surgeries
during pregnancy involving cardiopulmonary bypass (CPB),
found the following in women: per 100 pregnancies, the pooled
unadjusted estimate of maternal mortality was 11.2 (95%
CI: 6.8–17.8), pregnancy loss was 33.1 (95% CI: 25.2–41.2),
maternal complications were 8.8 (95% CI: 2.8–24.2) and neonatal
complications were 10.8 (95% CI: 4.2–25.2).
6
Thrombosis of prosthetic valves is a medical/surgical
emergency and all healthcare workers attending to pregnant
women with prosthetic valves should have a high index of
suspicion for valve thrombosis and resultant valve dysfunction.
It can be life-threatening and appropriate management reduces
maternal and foetal adverse outcomes.
7
Pregnant women are
at greater risk for valve thrombosis due to poor compliance
secondary to risk of possible foetal affectation, poor knowledge
of healthcare workers in counselling patients on the different
anticoagulation regimes in pregnancy, resource limitations in
terms of assessments and monitoring, poor access to healthcare,
nausea and vomiting during pregnancy, and a reduction in
fibrinolysis and anti-thrombin III, contributing to the
prothrombotic nature of pregnancy.
5
Open-heart surgery carries considerable risk, especially in
early pregnancy.
8
Therefore, CVD is considered a significant
non-obstetric cause of maternal mortality.
9
In resource-limited
countries such as South Africa, the management of such patients
is challenging due to the obstetric risks and complications of
anticoagulant therapy.
9
The following are six cases of pregnant patients on
anticoagulant therapy with malfunctioning prosthetic mitral
valves, seen during the period of a year at two tertiary institutions
in KwaZulu-Natal, requiring emergent valve replacement.
Case reports
Patient 1
A 30-year-old patient, P3G4, presented at 15 weeks’ gestation.
She had a routine echocardiography, which revealed dysfunction
of a single mitral leaflet. This was confirmed by fluoroscopy.
The patient had defaulted on multiple follow-up appointments
and obtained warfarin from her local clinic. She had utilised an
Department of Obstetrics and Gynaecology, University of
KwaZulu-Natal, Grey’s Hospital, Pietermaritzburg, South
Africa
S Foolchand, MB ChB, FCOG (SA), Certificate Maternal-Foetal
Medicine,
foolchand.s@gmail.comDepartment of Obstetrics and Gynaecology, University
of KwaZulu-Natal, Inkosi Albert Luthuli Central Hospital,
Durban, South Africa
H Ramnarain, MB ChB, FCOG (SA)