CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 4, May 2012
AFRICA
217
investigations done and all maternal and foetal complications.
All data were captured onto a structured data form.
The policy states that pregnant women with MPHV receive
heparin in the first trimester, which is switched to warfarin in
the second trimester and then replaced by intravenous heparin at
37 weeks prior to delivery. Heparin is stopped six hours before
elective caesarean section (C/S) or induction of labour and
re-started 12 hours post C/S or six hours post vaginal delivery
if no bleeding complication has occurred. Warfarin, usually 10
mg, is given on the first day, simultaneously with intravenous
heparin and the doses adjusted until the INR is 2.5–3 on two
consecutive occasions; heparin is then stopped. All patients were
treated according to this policy.
Descriptive statistics were used and all results are presented as
frequencies, means and percentages.
Results
Over the five-year study period, 1 021 hospital records of
patients with cardiac disease were identified. Sixty-one (6%) had
prosthethic valves, mean age 24 (15–45) years. Thirteen (21%)
presented in the first trimester; 37 (61%) in the second and 11
(18%) in the third trimester. Fifty-three (85%) were aged
≤
30
years and 34 (56%) were primigravidae. The demographic and
relevant clinical details are shown in Table 1.
9
In addition to
prosthetic heart valve replacements, five patients had associated
medical conditions, namely systemic lupus erythematous (
n
=
1),
tuberculosis (
n
=
1), insulin-dependent diabetes mellitus (
n
=
1),
parathryoidism (
n
=
1) and epilepsy (
n
=
1).
The dosage details of prophylactic anticoagulation therapy
are shown in Table 2 (
n
=
56). Two patients had bioprosthetic
valves and were not on any anticoagulation therapy, while three
with MPHV had stopped anticoagulation of their own accord
prior to pregnancy. Forty-seven patients had isolated mitral
valve replacements, 11 had mitral and aortic valve replacements
and one an aortic valve replacement for a mean duration of 10
(7–21) years.
Five patients had thrombotic events. Four with isolated mitral
valve prostheses were found on admission to hospital to have
thrombosis on echocardiography. The characteristics of four
patients with mechanical heart valve thrombosis are shown in
Table 3. Three of these patients had repeat MPHV surgery prior
to delivery and one at the time of elective C/S. The details of all
valve replacement data are shown in Fig. 1.
The fifth patient with a thrombotic event resulted in a
maternal death. The brief details are as follows: a 24-year-old
P1G2 presented at 34 weeks gestational age, had a mitral valve
replacement and was on warfarin 5 mg daily. Following the
stabilisation of her INR at a warfarin dose of 2.5 mg for five
to seven days, she complained of severe headache and her INR
was 6. The patient was given frozen plasma to stabilise her INR.
Shortly thereafter she complained of severe headache and had a
low Glasgow coma scale (GCS). CT scan revealed a large left
intracerebral bleed. A post mortem C/S was performed and a
2.6-kg live baby with good Apgar scores was delivered.
Echocardiography was performed in all patients. The mean
ejection fraction in 57 patients was 55% (range: 34–70) and in
four patients
<
45%. Five patients showed dilated right ventricle
and right atrium. Another patient showed dilated right atrium;
one had an ascending aortic aneurysm and another patient had
an aneurysm of the aortic root. Two patients had secondary
pulmonary hypertension; three had vegetations and were treated
for infective endocarditis.
There were 41 live births, two of which ended in early
neonatal deaths. There were six stillbirths and 12 miscarriages.
The mode of delivery and foetal outcomes are shown in Table 4.
TABLE 1. BASELINE CHARACTERISTICS OFALL PREGNANT
WOMENWITH PROSTHETIC HEARTVALVES
Characteristics
Number (
n
=
61)
Maternal age (years)
Mean (range)
24 (16–45 )
Age groups (years)
15–20
17
21–25
23
26–30
13
>
30
8
Parity
P0
34
P1
17
P2–3
4
P0+1
3
P0+4
1
P1+1
2
Gestational age (weeks) on admission
<
14
18
14–28
32
28–38
11
History of previous pregnancies
Miscarriage
6
Intrauterine death
3
Stillbirth (MSB)
2
Neonatal death
2
HIV status
Negative
43
Positive
16
CD
4
>
200 cells/ml
14
CD
4
<
200 cells/ml
2
Declined
2
NYHA functional class
1
49
11
6
111
4
1V
2
NYHA – NewYork Heart Association classification.
9
TABLE 2. DOSAGE DETAILS OFANTICOAGULATION
USED BY PATIENTS ON PRESENTATIONAT THE
FIRSTANTENATALVISIT (
n
=
56)
Dose of anti-
coagulation drug
Trimester 1
(
n
=
12)
n
(%)
Trimester 2
(
n
=
35)
n
(%)
Trimester 3
(
n
= 9)
n
(%)
Warfarin
2.5 mg
1 (8)
0 (0)
0 (0)
5 mg
6 (50)
23 (66)
5 (56)
7.5 mg
3 (25)
7 (20)
3 (33)
10 mg
0 (0)
1 (3)
1 (11)
40 mg
1 (8)
0 (0)
0 (0)
7.5 mg alt 5 mg
1 (8)
2 (6)
0 (0)
10 mg alt 7.5 mg
0 (0)
2 (6)
0 (0)
