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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 2, March/April 2016
AFRICA
113
filling of the left ventricle, promoting cardiac decompensation.
In addition, preload reduction is associated with the risk of
declining cardiac output.
25
Patients with severe mitral stenosis (valve area
<
1.0 cm
2
) have
high rates of complications and are likely to decompensate. In
these patients and those who remain symptomatic despite medical
treatment, elective percutaneous balloon valvuloplasty should
be considered if the valve is suitable for the procedure, ideally
during the second trimester, before 20 weeks of gestation.
19,26,27
Patients with moderate stenosis (valve area 1.0–1.5 cm
2
) should
be monitored closely and may require intervention. Mitral
regurgitation may develop following valvotomy but this is
usually better tolerated than a stenotic disease.
19
Whether or not a woman is suitable for mitral valvotomy
depends on the findings of echocardiographic assessment of
the mitral valve apparatus. The mobility, thickness and degree
of calcification of the leaflets are assessed, as is the structure
of the subvalvular apparatus. Those with calcification of the
commissures or significant mitral regurgitation are generally
unsuitable for the procedure.
24
If percutaneous valvuloplasty is
not available, closed commissurotomy remains an alternative.
Open-heart surgery should be reserved for patients without other
options, when the mother’s life is threatened.
28
Aortic stenosis (AS)
Aortic stenosis in pregnancy is a rare condition. It is mostly
associated with congenital bicuspid aortic valve (which may be
linked to aortopathy and risk of aortic dissection) and is not
usually the result of rheumatic disease.
29
A diagnosis of AS is
generally made pre-pregnancy and this allows for counselling,
optimisation of maternal care, and planning of antenatal
care. Echocardiographic quantification of AS severity and
measurement of aortic diameter should be performed before
pregnancy. Exercise testing is recommended in asymptomatic
patients to confirm asymptomatic status and evaluate exercise
tolerance, blood pressure response, arrhythmias, and the need
for interventions.
28
Features that predict a favourable outcome
during pregnancy include absent symptoms, normal ECG,
normal exertional blood pressure rise, aortic valve area ≥ 1 cm
2
and normal left ventricular function.
30
Pregnancy is usually well tolerated in asymptomatic AS,
even when severe, as long as the patient remains asymptomatic
during exercise testing and has a normal blood pressure response
during exercise.
31,32
Pregnancy should not be discouraged
in asymptomatic patients, even with severe AS, when left
ventricular size and function as well as the exercise test result
are normal. Cardiac deterioration due to AS may be indicated
by worsening breathlessness, syncope, chest pain, deterioration
in left ventricular ejection fraction, a reduction or failure to
increase transvalvular gradient (it should normally increase by
20% during pregnancy), and/or ischaemic ECG changes.
Symptomatic patientswith severeASor asymptomatic patients
with impaired left ventricular function or a pathological exercise
test should be counselled against pregnancy, and valvuloplasty
or surgery should be performed before pregnancy.
28,32
Medical
therapy involves the use of diuretics and cautious beta-
blockade at a low initial dose to avoid pre-syncope, syncope and
hypotension. Vasodilators should be avoided. Failure of medical
therapy can be managed, if gestational age allows, by delivery
of the foetus, which results in significant improvement in the
maternal cardiac status.
Percutaneous valvuloplasty can be undertaken in
non-calcified valves with minimal regurgitation when severe
symptoms persist.
33
Valve replacement should be reserved for
life-threatening symptoms, after early delivery by cesarean
procedure, if this is an option. Cesarean delivery should be
considered in severe, particularly symptomatic aortic stenosis.
34
Regurgitant lesions
The effects of rheumatic mitral regurgitation are usually
ameliorated in early pregnancy by the dominant physiological
change, peripheral vasodilatation. The increased plasma volume
is offset by the reduction in systemic vascular resistance and
consequently, the extent of the regurgitation diminishes. The
plasma volume, however, peaks in the middle of the third
trimester and that, together with a rise in vascular resistance,
may lead to worsening regurgitation and the onset of symptoms
and signs consistent with fluid overload or pulmonary oedema.
Hypertension may also precipitate similar cardiovascular
symptoms at an earlier stage of plasma volume expansion.
These patients respond well to diuretic therapy and usually no
further intervention is necessary to secure the successful outcome
of the pregnancy. Patients with severe regurgitation require
expert evaluation to assess the risks and benefits of surgical
intervention and the timing in relation to pregnancy. Severely
symptomatic women, those with impaired left ventricular systolic
dysfunction, or women with pulmonary hypertension are at high
risk of maternal and foetal complications.
An enlarged left atrium increases the risk of developing
atrial fibrillation. If valve surgery is indicated in women of
childbearing age who have severe mitral regurgitation, valve
repair should be offered when possible, thus avoiding the risks
of bioprosthetic valve degeneration and early repeat surgery
or anticoagulation, thrombosis and embolism associated with
a mechanical valve. A woman with symptomatic mitral valve
disease who is not a candidate for repair or replacement of the
valve should be advised against pregnancy.
Aortic regurgitation (AR) is less common and those of
rheumatic aetiology are usually associated with some degree
of mitral incompetence as well.
35
The most frequent cause of
AR in women of childbearing age is also bicuspid aortic valve.
The presentation during pregnancy is similar to that of mitral
regurgitation and the management follows the same principles.
Chronic, moderate or even severe aortic regurgitation is
usually well tolerated if left ventricular function is preserved;
nevertheless, women with severe aortic regurgitation are at a
risk of developing pulmonary oedema and arrhythmias during
pregnancy. Valve replacement during pregnancy for treatment of
aortic regurgitation is rarely required and should be considered
only in women with symptoms refractory to medical therapy.
24
Isolated tricuspid and pulmonary valve incompetence is
unlikely to be of rheumatic origin and therefore not considered
further here.
Mixed lesions
Generally, the risks of mixed valvular lesions depend upon the
dominant abnormality. Left-sided cardiac valvular disease is