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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 26, No 3, May/June 2015
AFRICA
131
arrhythmia due to myocardial ischaemia.
5,10
The patients were classified according to their ages: whether
they were younger than 65 years or older. The mortality rate,
complications of IABP, intra-operative properties, pre-operative
clinical characteristics of patients, and length of stay in the
intensive care unit (ICU) were recorded.
The pre-operative parameters of the patients were age, gender,
re-operation, hypertension, body mass index, diabetes mellitus,
chronic renal failure, the value of the EuroSCORE, previous
cerebrovascular accidents, left ventricular ejection fraction, left
main coronary artery disease, chronic obstructive pulmonary
disease (COPD), and the presence of a myocardial infarction
more recently than one week previously. The pre-operative
clinical characteristics, postoperative complications, duration of
ICU and hospital stays, and mortality rates of the groups were
compared.
Statistical analysis
Demographic characteristics were compared using mean and
median values. Parametric results were evaluated using the
Student’s
t
-test and Tukey test. The chi-square method, Pearson’s
test, and Fisher’s test were used to analyse the categorical
parameters. Risk factors for mortality were assessed using a
binary logistic regression analysis. The standard deviation value
of
p
<
0.05 was considered significant. SPSS 18 was used for the
statistical analysis.
Results
In this study, 138 of the 190 patients were male. The mean patient
age was 62.7
±
9.9 years. Ninety-eight patients were younger than
65 years of age, and 90 patients were 65 years of age or older.
The number of patients with COPD and the mean
EuroSCORE of the patients were higher in the older group.
In contrast, the number of patients with diabetes mellitus was
higher in the younger group. In terms of other demographic
characteristics, there were no statistically significant differences
between the groups (Table 1). The mean CPB times, mean cross-
clamp times, and number of grafts used were similar between the
two groups (Table 2).
Fifty-seven (30.1%) patients died in the first 30 days following
the operation. Twenty-three of these patients were in the younger
group. The mortality rate of the younger group was significantly
lower compared to the older patients (
p
=
0.043). In the subgroup
analysis, the mortality rate of emergent operations was similar
in the both groups (
p
=
0.964). However, the mortality rate was
higher in the older group for elective operations (
p
=
0.018).
Among the surviving patients, the number of older patients,
rate of emergency operations, mean EuroSCORE values, and
number of patients with chronic renal failure were lower
than that in the group of patients who died (Table 3). Binary
logistic regression analysis showed that the only factor affecting
mortality was prolonged CPB time. However, in the subgroup
analysis of patients without emergency conditions, age was the
second determinant of mortality (
p
=
0.018, OR
=
5.5).
In the subgroup analysis, CPB time and pre-operative chronic
renal failure were independent risk factors for mortality in the
older group. In the younger group, female gender, diabetes
mellitus, high EuroSCOREs, emergency operations, prolonged
CPB (
p
=
0.001, OR
=
7.6), and prolonged stays in the ICU were
independent risk factors for mortality (Table 4).
In our study, a few serious complications were observed due
to IABP support. Iliac artery injury occurred in two patients and
peripheral ischaemia was observed in three patients. The other
complications were thrombocytopenia and minor bleeding at
the catheter site (Table 5). The rate of complications was similar
between the groups.
Discussion
Postoperative recovery in elderly patients requires a longer time
period than for younger patients. Postoperative atrial fibrillation
requiring medical treatment, and other complications occur
more frequently in the elderly; the total intubation time was also
longer for this group. Therefore, delayed recovery in the elderly
may simply be due to the aging process affecting all organs.
9
For
this reason, elderly patients may need more mechanical support
in cases of low cardiac output following CPB.
Table 1. Demographic characteristics of the patients
Younger
group
(
n
=
98)
Older
group
(
n
=
92) Total
p
-value
Gender (M:F)
74/24
64/28 138/52 0.358
Mean age (years)
54.7
±
6.1 71.4
±
4.5 62.7
±
9.9
<
0.001
Mean EF (%)
37.1
±
8.3 39.2
±
9.5 38.1
±
8.9 0.121
MI,
n
(%)
31 (31.9)
24 (26) 55 (27.7)
0.400
COPD,
n
(%)
5 (5.1)
13 (14.1)
18 (9)
0.034
CRF,
n
(%)
3 (3)
5 (5.4)
8 (4.2)
0.487
Redo,
n
(%)
3 (3)
0
3 (1.5)
0.297
HT,
n
(%)
47 (48)
56 (60)
103 (54)
0.074
DM,
n
(%)
48 (49)
23 (25) 71 (37.3)
0.001
CVA,
n
(%)
4 (4.1)
5 (5.4)
9 (4.7)
0.745
Recent MI,
n
(%)
18 (18.3) 16 (17.4) 34 (17.9)
0.861
EuroSCORE
4 (0–10) 5 (2–10) 4 (0–10)
<
0.001
BMI (kg/m
2
)
27.2
±
4 26.7
±
4.4 27.2
±
4.1 0.112
LMCA,
n
(%)
8 (8.1)
5 (5.4)
13 (6.8)
0.457
Prophylactic levosi-
mendan,
n
(%)
18 (18.3)
12 (13) 30 (15.8)
0.315
Emergency,
n
(%)
18 (18.3) 16 (17.4) 34 (17.8)
0.861
Pre-operative IABP,
n
(%) 8 (8.1)
9 (9.7)
17
0.405
COPD: chronic obstructive pulmonary disease, CRF: chronic renal
failure, HT: hypertension, DM: diabetes mellitus, CVA: cerebrovascu-
lar accident, BMI: body mass index, LMCA: left main coronary artery
disease, EF: ejection fraction.
Table 2. Mortality rates and clinical outcomes of the patients
Younger group Older group
p
-value
Mortality,
n
(%)
23 (23.4)
34 (36.9)
0.043
Mortality,
n
(%)*
8 (44.4)
7 (41.1)
0.964
Mortality,
n
(%)**
15 (18.7)
27 (36)
0.018
CPB time (min)
143
±
59
140
±
58
0.786
Graft number
3.1 (2–5)
3.2 (2–5)
0.789
Cross-clamp time (min)
90
±
34
88
±
38
0.604
ICU time (day)
5.9
±
4
6.6
±
5
0.284
ICU: intensive care unit. CPB time: cardiopulmonary bypass time,
*patients with emergency operation, **patients undergoing elective
operation.