Cardiovascular Journal of Africa: Vol 28 No 3 (May/June 2017)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 3, May/June 2017

192

AFRICA

with the amended Declaration of Helsinki and Good Clinical

Practice 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

Following cross-clamping of the aorta, the heart was arrested

using 10–15 cm

/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 cm

/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

-test and Mann–Whitney

-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

-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

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 (

0.680 and

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 show

significant 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).

Pre-operative, first hour postoperative, POD 1 and POD 5

microalbuminuria levels were 16.5

17.2, 28.5

17.2, 59.0

29.8 and 23.0

20.0 mg/l in group T, and 30.0

17.7, 51.0

28.4, 75.0

25.6 and 52.5

27.5 mg/l in Group N-T, respectively,

and there were statistically significant differences between four