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RESEARCH ARTICLE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
58
VOLUME 14 NUMBER 2 • DECEMBER 2017
regulations. Written informed consent was obtained from all
subjects. Patients admitted to the Department of Cardiovascular
Surgery of our tertiary centre between June 2006 and February
2007 who had type 2 diabetes mellitus and had undergone CABG
surgery constituted the study group.
Patients were divided into two groups with block randomisation,
using the sealed envelope technique: group T (telmisartan group)
consisted of patients who received the angiotensin receptor
blocking agent, telmisartan (Micardis
®
, Boehringer Ingelheim,
Istanbul, Turkey) 80 mg daily for at least six months in the pre-
operative period; group N-T (non-telmisartan group) consisted
of patients who received neither telmisartan nor any other
angiotensin receptor blockers. In both groups, no patients were
using angiotensin converting enzyme inhibitors for at least six
months prior to the study.
Cases with severely impaired left ventricular function, chronic
pulmonary obstructive disease, severe systemic non-cardiac
disease, severe renal or liver impairment, infectious diseases
before surgery, malignancy, those receiving corticosteroids or
other immunosuppressive treatment, and patients with stroke,
inflammatory disease, and/or previous cardiac surgery, and valvular
heart disease were excluded from the study.
Surgical technique and postoperative care
Cardiac medication, including beta-adrenergic blocking agents,
calcium channel blocking agents and nitrates, was continued until
the morning of surgery. The same general anaesthetic drugs were
used in all patients. A standard median sternotomy incision was
used to expose the heart and place the internal mammary artery
and saphenous vein grafts used for coronary anastomosis.
In each group, routine surgery was performed using a
membrane oxygenator (Edwards Vital, Edwards Lifesciences LLC,
Irvine, CA, USA), a 3-mg/kg dose of sodium heparin, 2 000 ml of
Ringer’s lactate primer and a roller pump at a body temperature of
28°C. Cardiopulmonary bypass was instituted via the ascending
aorta and single two-stage venous cannulation (maintained at
2.2–2.4 l/min/m
2
).
Following cross-clamping of the aorta, the heart was arrested
using 10–15 cm
3
/kg cold blood cardioplegia through the aortic root
and topical ice slush was continued every 20 minutes for myocardial
protection. Heparin was neutralised with protamine hydrochloride
(Protamin 1000; Roche, Istanbul, Turkey). The circuit was primed
with 2 000 ml Ringer’s lactate.
After completion of the surgery, patients were transferred to the
intensive care unit (ICU), where standard care and processes were
followed until discharge. Patients were weaned from mechanical
ventilation when they were haemodynamically stable, responding
to verbal stimulation, and had been fully rewarmed. Patients were
discharged from the ICU if they were haemodynamically stable,
had normal blood gasses during spontaneous breathing, and had a
satisfactory renal function.
Outcome parameters and other variables
Smoking, obesity, hypertension, duration of diabetes, family history
of coronary artery disease, pre-operative myocardial infarction,
and pre-operative haemodynamic data were recorded. During the
surgical procedure, haemodynamic parameters, including heart
rate, mean arterial pressure, central venous pressure, arterial blood
gasses and urine output were monitored.
In the postoperative period in the ICU, cardiovascular and
respiratory values and temperature were recorded every 15 minutes
before extubation and then hourly until discharge from the ICU.
The length of stay in the ICU was also recorded.
Microalbuminuria levels were studied pre-operatively, on the
first hour postoperatively, and on postoperative days (POD) one and
five. High-sensitivity C-reactive protein (hsCRP) levels were studied
pre-operatively, and on POD 1 and 5. Patients who were considered
to be in a low-cardiac output state received positive inotropic
agents (dopamine or adrenaline or both). They were assessed
for persistent systemic blood pressure below 90 mmHg, urinary
output lower than 20 cm3/h, and the state of peripheral circulation
was evaluated for adequate preload and optimal afterload. Urine
samples were measured for microalbuminuria using Micral test
sticks (Roche).
Statistical analysis
Categorical variables were analysed with chi-squared and Fisher’s
exact tests, as appropriate, in contingency tables, whereas the
unpaired
t
-test and Mann–Whitney
U
-test were performed, as
appropriate, for comparison of continuous variables. Comparisons
for microalbuminuria and hsCRP levels in the groups were done
with repeated measures of ANOVA and the Bonferroni test.
Data are expressed as means ± standard deviation. A
p
-value <
0.05 was considered statistically significant. All statistical analyses
were performed with the Statistical Package for Social Sciences
(SPSS 10.0 for Windows, SPSS, Inc., Chicago, IL).
The calculation of sample size was based on a power analysis. At
a power of 80% using a significance level of
p
< 0.05, the sample
size required was 20 subjects per study group.
Results
Forty patients met the eligibility criteria for the study. Of the 40
patients (29 males, 11 females) whose charts were reviewed, the
average age was 65.0 ± 8.6 (range 40–79) years. Group T included
20 patients (15 males, 5 females) with a mean age of 65.6 ± 7.8
years, who had been using telmisartan 80 mg daily for at least six
months. Group N-T included 20 patients (14 males, 6 females) with
a mean age of 64.4 ± 9.5 years, who used no angiotensin receptor
blocking agent prior to the operation. The groups were similar with
regard to age and gender (
p
= 0.680 and
p
= 0.723, respectively).
With regard to clinical characteristics such as body mass index,
smoking habit, hypertension, hyperlipidaemia, and history of
myocardial infarct, the two groups did not showsignificant differences
and were comparable (Table 1). The groups were also similar with
regard to number of bypass grafts, cardiopulmonary bypass time,
cross-clamp time, flow, atrial fibrillation, inotrope usage, time of
endotracheal intubation and mortality rate (Table 2).
Table 1.
Clinical and demographic characteristics of the study group
Characteristics
Group T Group N-T
p
-value
Age (years)
65.6 ± 7.8 64.4 ± 9.5
0.680
Gender (M/F)
15/5
14/6
0.723
Body mass index
28.0 ± 4.7 26.5 ± 2.8
0.234
Smoking,
n
(%)
11 (55)
10 (50)
0.752
Hypertension,
n
(%)
18 (90)
16 (80)
0.661
Hyperlipidaemia,
n
(%)
19 (95)
18 (90)
1.000
History of myocardial infract,
n
(%)
12 (60)
13 (65)
0.744
Group T = telmisartan group; group N-T = non-telmisartan group.