51 / 74
CARDIOVASCULAR JOURNAL OF AFRICA • Volume 25, No 5, September/October 2014
AFRICA
245
Pre-operative patient characteristics
The study consisted of 114 patients, including 22 (19.3%)
aged
≥
80 years. The mean age was 76.6
±
3.6 years (range
70–87). Baseline demographic characteristics and clinical data
are presented in Table 1.
A total of 110 patients (87.7%) had at least one or more
extra-cardiac co-morbidity, such as pulmonary disease (
n
=
26),
cerebrovascular accident (
n
=
7), peripheral artery disease (
n
=
1),
or renal failure (
n
=
11). Coronary angiography revealed significant
lesions in 28 patients (24.5%), including five with left main
coronary artery disease (LMCA). Twenty-three patients (20.2%)
had logistic EuroSCORE
≥
15. Ninety-eight patients (86%) had
NYHA (LMCA) class III–IV symptoms, whereas 16 patients
(14%) had clinical manifestations of congestive heart failure.
Seventeen patients (14.9%) had chronic atrial fibrillation,
including two with a pacemaker. The common pathology
of the valve was aortic stenosis in 97 patients (85.1%), while
22 (19.3%) had concomitant aortic regurgitation. Only 17
patients had uncomplicated pure regurgitation. Transthoracic
echocardiography showed that 10.5% of patients (
n
=
12) had
poor left ventricular function, defined as LVEF
<
40% (Table 2).
Surgical data
A median sternotomy was performed in all patients.
Cardiopulmonary bypass (CPB) equipment was uniform:
systemic moderate hypothermia was employed along with
antegrade
±
retrograde isothermic blood perfusion in case of
aortic valve regurgitation. Three patients (2.6%) had a history of
previous CABG surgery.
A mechanical valve was implanted in all but 22 patients
(19.2%) received bioprosthetic valves. The proportion of
bioprothetic valve replacement was higher in patients aged
≥
80
years (27.2 vs 17.3%). We mostly used bileaflet prostheses based
on our experience with mechanical valve implantation and due
to the poor socio-economic status of the country in those years.
Isolated aortic valve replacement was performed in 61
patients (53.5%), whereas 29 underwent concomitant CABG
surgery, 12 received mitral valve surgery, and 13 patients received
interpositional graft replacement of the ascending aorta, including
a flanged Bentall de Bono procedure due to type I dissection in
one patient. The mean CPB time was 139.9
±
73.7 min, while the
mean aortic cross-clamp time was 96
±
41.5 min (Table 3).
Sixty patients (52.6%) required inotropic support for
haemodynamic recovery, either in the operating room or during
the postoperative period. Twelve received intra-aortic balloon
pump (IABP) support. The chi-square test showed a significant
correlation between the logistic EuroSCORE and inotropic
support. In addition, 19 patients (82.6%) with EuroSCORE
≥
15 needed pharmacological support (
p
=
0.001). Patients
with LMCA stenosis (
p
=
0.008), NYHA
≥
3 (
p
=
0.033) and
EuroSCORE
≥
15 (
p
=
0.002) were found to be correlated for
the use of IABP.
International normalised ratio (INR) levels were measured
daily and postoperative anticoagulant therapy was administered
with oral sodium warfarin in all patients. Three-month therapy
following bioprosthetic valve replacement was prescribed.
Statistical analysis
Statistical analysis was performed using the SPSS software
v12.0 (SPSS Inc, Chicago, IL, USA). Continuous variables are
expressed as mean
±
standard deviation or percentages. The
Student’s
t
-test and Mann–Whitney
U
-test were used to compare
differences among the variables.
Table 2. Pre-operative measurements
Number
%
Pre-operative AF
17
14.9
Pacemaker
2
1.8
Echocardiography
Aortic stenosis (AS)
97
85.1
Aortic regurgitation (AR)
22
19.3
LVEF (mean)
56.9
±
9.3
(35–78)
LVEF
<
40%
12
10.5
Aortic area (cm
2
)
0.8
±
0.3
(0.4–1.35)
Max gradient (mmHg)
81.2
±
25
(0–160)
Mean gradient (mmHg)
50.3
±
16.4
(0–110)
AF: atrial fibrillation; LVEF: left ventricular ejection fraction.
Table 1. Baseline demographic characteristics and clinical data
Number
%
Median age (years)
76.6
±
3.6
(70–87)
Women/men
50/64
43.8/56.1
Hypertension
88
77.2
Diabetes
26
22.8
Chronic pulmonary disease
26
22.8
Pulmonary hypertension
8
7
Cerebrovascular disease
7
6.1
Peripheral vascular disease
1
0.9
Coronary artery disease
28
24.5
Chronic renal failure
11
9.6
Dyspnoea
75
65.8
NYHA
Class II
14
12.3
Class III
81
71.1
Class IV
17
14.9
Angina pectoris
56
49.1
Previous MI
33
28.9
EuroSCORE
<
15
91
79.8
> 15
23
20.2
NYHA: New York Heart Association; MI: myocardial infarction.
Table 3. Intra-operative data
Number
%
Re-operation
6
5.2
Isolated AVR
61
53.5
AVR+ concomitant surgery
CABG
29
25.4
Mitral valve surgery
12
10.5
CABG + MVR
1
0.8
Tubular graft interposition
13
11.4
Valve size (mm)
2.89
Aortic cross clamping time (min)
96
±
41.5
(26–240)
Cardiopulmonary bypass time (min) 139.9
±
73.7
(46–480)
Postoperative inotropic support
60
52.6
IABP support
12
10.5
AVR: aortic valve replacement; CABG: coronary artery bypass graft-
ing; MVR: mitral valve replacement; IABP: intra-aortic balloon
pump.