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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 2, March/April 2016
AFRICA
115
mitral or aortic valvular heart disease. The development of
pulmonary hypertension in this setting does not necessarily
imply a worsening prognosis. A prospective Canadian study
identified rheumatic valvular disease as being the single most
common cause for pulmonary hypertension, accounting for
52% of cases, but was not associated with any independent
increase in risk for pregnant women with left heart obstruction.
43
The authors of this article noted that reactive pulmonary
hypertension may have a different prognosis from those with
primary hypertension, although there is no clarity on this issue.
The risk of maternal morbidity and mortality (17–50%)
is however, generally reported to be high in all categories of
pulmonary hypertension. Mortality occurs mainly in late
pregnancy and after delivery, owing to heart failure, pulmonary
thrombosis and arrhythmias.
44
Recent evidence showed better
outcomes in women with mild pulmonary hypertension
(systolic pulmonary arterial pressure
<
50 mmHg), however, no
safe cut-off value is known.
45
There is limited literature and research into the treatment
of pulmonary hypertension during pregnancy.
46
In a recent
small series, no mortality occurred when nebulised iloprost
was started early during pregnancy, upgraded to intravenous
iloprost in some cases, with the addition of sildenafil when
clinically indicated.
47
These medications are favoured over
endothelin receptor antagonists, which are teratogenic.
34,47
Of the various treatment options, the use of pulmonary
vasodilator therapy with sildenafil is currently under ongoing
investigation and there is insufficient experience to make any
recommendations.
Heart failure complicating rheumatic valvular heart disease
in pregnancy has been described in 22% of women with
valvular rheumatic disease presenting for care in 12 different
African countries, Yemen and India.
48
The onset of pulmonary
oedema may be related to fluid overload during pregnancy,
resulting from the combined alterations in intravascular volume
and peripheral resistance characteristic of normal pregnancy,
but may be precipitated by the injudicious use of intravenous
fluids. An increasingly hyperdynamic circulation caused by the
development of anaemia, subclinical hyperthyroidism, infection
or the onset of labour itself may also lead to pulmonary
oedema. Hypertension, whatever the precipitating mechanism,
will increase left-sided filling pressures during pregnancy, with
an attendant risk of pulmonary oedema. Treatment is directed
towards anticipation and prevention of precipitating causes;
the treatment of the cardiac lesion itself is usually combined
with diuretic therapy.
An American study found that endocarditis has a rising
incidence, with rates increasing from 11 per 100 000 population
to 15 cases per 100 000 population.
49
Similar trends have been
seen in the United Kingdom, and the temporal relationship
of this increase to the promulgation of a revised guideline
advocating more conservative use of prophylactic antibiotics for
individuals having interventions associated with bacteraemia is
clearly demonstrable.
50
Cardiac valves damaged by rheumatic
disease are associated with turbulent blood flow, and bacteraemia
triggers infection on the valve itself.
The most frequently implicated organisms are
Staphylococcus
aureus
, followed by streptococci and other gram-negative
organisms. Fungi can result in infection of the valve. Obstetric
practice is confronted by high rates of sepsis at the time of
parturition; risk factors that identify a greater probability of
infection include rupture of the membranes, prolonged labour,
multiple vaginal examinations during labour, instrumentation
of the genital tract, surgical delivery, co-morbidity with HIV
infection, and exposure to virulent organisms, especially group
A streptococcal infection. Consequently, prophylactic antibiotics
should be administered routinely according to established
guidelines.
Principles of combined obstetric and cardiac
management
Prior to pregnancy, the severity of the cardiac condition and the
cardiovascular reserve of each patient should be assessed. All
women who reach childbearing age should have a discussion with
their physician about the maternal and foetal risks a pregnancy
would pose. In addition, drug therapy should be reviewed with
the patient, particularly when potentially teratogenic drugs such
as warfarin are involved. These women should be made aware
of the risks of an unplanned pregnancy and should have a safe
environment in which to initiate a discussion about planning a
pregnancy. Contraception should also be discussed and offered
to these young women.
51
A multidisciplinary team involving the
obstetrician, cardiologist, anaesthetist, neonatologist and on
occasion, a cardiothoracic surgeon, is vital to the successful
management of the pregnant women with heart disease.
51
ESC guidelines and WHO risk stratification
The European Society of Cardiology (ESC) guidelines on
the management of cardiovascular disease during pregnancy
recommend that all women with maternal heart disease should
have a risk assessment performed at least once prior to pregnancy
and then again during pregnancy.
34
This risk assessment should
be according to the modified World Health Organisation
(WHO) risk classification, which integrates all known maternal
cardiovascular risk factors, illustrated in Tables 2–5.
Table 2. Risk classification
Risk
class
Risk of pregnancy by medical condition
I No detectable increased risk of maternal mortality and no/mild
increase in morbidity.
II Small increase risk of maternal mortality or moderate increase in
morbidity.
III Significantly increased risk of maternal mortality or severe morbidi-
ty. Expert counselling required. If pregnancy is decided upon, inten-
sive specialist cardiac and obstetric monitoring needed throughout
pregnancy, childbirth and the puerperium.
IV Extremely high risk of maternal mortality or severe morbidity;
pregnancy contra-indicated. If pregnancy occurs, termination
should be discussed. If pregnancy continues, care as for class III.
Table 3.WHO class I
• Uncomplicated, small or mild
–– pulmonary stenosis
–– patent ductus arteriosus
–– mitral valve prolapse
• Successfully repaired simple lesions (atrial or ventricular septal defect,
patent ductus arteriosus, anomalous pulmonary venous drainage).
• Atrial or ventricular ectopic beats, isolated