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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 5, September/October 2018
AFRICA
289
Haemorrhage and other complications in pregnant
women on anticoagulation for mechanical heart valves:
a prospective observational cohort study
S Kariv, F Azibani, J Baard, A Osman, P Soma-Pillay, J Anthony, K Sliwa
Abstract
Objective:
To document maternal and foetal morbidity and
mortality in anticoagulated, pregnant patients with mechani-
cal heart valves until 42 days postpartum.
Methods:
In a tertiary single-centre, prospective cohort, 178
consecutive patients at the cardiac-obstetric clinic were screened
for warfarin use between 1 July 2010 and 31 December 2015.
Of 33 pregnancies identified, 29 were included. Patients
received intravenous unfractionated heparin from six to 12
weeks’ gestation and peripartum, and warfarin from 12 to 36
weeks. Maternal outcomes including death, major haemor-
rhage and thrombosis, and foetal outcomes were documented.
Results:
There were two maternal deaths, five returns to thea-
tre post-delivery, eight patients transfused, six major haemor-
rhages, one case of infective endocarditis and three ischaemic
strokes. Ten pregnancies had poor foetal outcomes (six
miscarriages, three terminations, one early neonatal death).
Twenty patients required more than 30 days’ hospitalisation,
and 15 required three or more admissions. HIV positivity was
associated with surgical delivery (
p
=
0.0017).
Conclusions:
Complication rates were high despite centralised
care.
Keywords:
warfarin, heparin, pregnancy, anticoagulation,
mechanical heart valves, Africa
Submitted 4/2/18, accepted 22/5/18
Published online 13/6/18
Cardiovasc J Afr
2018;
29
: 289–295
www.cvja.co.zaDOI: 10.5830/CVJA-2018-029
Rheumatic heart disease (RHD) is common in urban Africans,
with an estimated yearly incidence of 23.5 cases per 100 000
population aged over 14 years.
1
Mechanical prosthetic heart
valves (MHVs) require lifelong, uninterrupted anticoagulation
treatment, therefore,many femalepatients require anticoagulation
during childbearing years. This anticoagulation is essential
during pregnancy as without it, up to 25% of pregnant women
will experience a thrombotic event.
2
Cardiac disease is the most important non-obstetric cause
of maternal deaths,
3
and RHD is an important contributor.
4
Mortality and serious morbidity are higher in patients with
MHVs than in those with tissue valves, or those who have
cardiac disease without prosthetic valves. It has been reported
that only 58% of women with MHVs survive pregnancy without
any serious adverse events.
5
Although warfarin is the most effective anticoagulant in
preventing thrombotic complications,
2,6,7
its use in pregnancy
remains problematic. It is associated with warfarin embryopathy
if administered between six and 12 weeks’ gestation,
2,8
and
with foetal loss and stillbirth later in pregnancy.
7,9,10
Warfarin
crosses the placenta, placing the vitamin K-deficient foetus at
risk of haemorrhage.
6
Some findings suggest that certain foetal
complications of warfarin may be dose dependent,
11,12
but not
all studies have replicated these findings.
13
In some patients,
low doses may also result in sub-therapeutic anticoagulation.
Heparin, an alternative to warfarin, does not cross the placenta
14
but results in higher rates of thromboembolic complications.
6
The challenge of administering anticoagulation to pregnant
women with valve replacements includes management of the
underlying cardiac condition and its complications, as well as
the obstetric risks of the anticoagulant regimen. A low-resource
setting (such as South Africa) may further exacerbate these
difficulties, although there are limited data available to inform
local practice.
The objective of this study was to characterise the clinical
course of patients with MHVs needing anticoagulation in
pregnancy, and to document antenatal, intra-partum and post-
partum morbidity and mortality rates as well as foetal outcomes.
Methods
In the ongoing, single-centre, prospective Cardiac Disease in
Maternity (CDM) cohort study, 178 women with heart disease
Department of Medicine, Groote Schuur Hospital and
University of Cape Town, Cape Town, South Africa
S Kariv, MB BCh,
Sarah.kariv@gmail.comThe Cardiac Clinic, Department of Medicine, Groote
Schuur Hospital and University of Cape Town
F Azibani, PhD
J Baard, MB BCh
K Sliwa, PhD
Hatter Institute for Cardiovascular Research in Africa,
Department of Medicine, Faculty of Health Sciences and
IDM, University of Cape Town, Cape Town, South Africa
F Azibani, PhD
J Baard, MB BCh
K Sliwa, PhD
Department of Obstetrics and Gynaecology, Groote Schuur
Hospital and University of Cape Town, Cape Town, South
Africa
A Osman, MB BCh, FCOG
J Anthony, MB BCh, FCOG
Department of Obstetrics and Gynaecology, Steve Biko
Academic Hospital and University of Pretoria, Pretoria,
South Africa
P Soma-Pillay, MB BCh, FCOG