Cardiovascular Journal of Africa: Vol 28 No 1 (January/February 2016)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 1, January/February 2017

AFRICA

artery disease guidelines.

10-14,15

The NCEP ATP III stressed the

cardiovascular risk factors associated with the MS.

In Turkey,

prevalence of the MS is as high as three out of every eight

people in the adult population.

Among coronary artery disease

patients, its prevalence is 42.7% in males and 64.0% in females,

with an overall prevalence of 53.0%.

In our study, 42% of the

patients had the MS, which is similar to other studies in MS

patients undergoing CABG (42, 48, 47%).

11,12,17

Although not statistically significant, MS patients also had

a higher smoking rate, which reflected their habits and lifestyle.

Patients with and without the MS did not differ in mortality

rates; mortality occurred in two patients in the MS group (3.1%)

and in one patient in the non-MS group (1.1%).

Other studies reported similar mortality rates in the two

patient groups.

11,12,17

Swart

et al

compared 370 patients with

the MS (as defined by the International Diabetes Federation

and NCEP ATP III criteria) and 503 patients without the MS

in terms of mortality and morbidity rates following CABG. The

two groups had a similar age distribution and had mortality

rates of 1.9 and 1.6%, respectively (

0.7348). The average

EuroSCORE differed significantly between the two groups,

being 3.26 (median 3) in the MS group and 3.61 (median 3) in the

non-MS group (

0.0494). The rates of re-exploration, stroke,

renal insufficiency, prolonged mechanical ventilation, and the

need for rewiring of sternal dehiscence were similar in the two

groups. The amount of mediastinal drainage was also similar

(624 vs 670 ml). The need for homologous blood transfusion was

less (

0.0012), but hospital stay was longer (

0.00001) in

the MS group. The authors concluded that MS did not have any

detrimental clinical effects on either pre-operative risk factors or

outcomes after CABG.

Özyazıcıo

et al

examined the effects of the MS on

postoperativemortality andmorbidity rates inpatients undergoing

CABG. Compared with patients without the MS, those with the

MS (NCEP ATP III criteria) had a higher incidence of wound

infection (

0.05), but similar rates of atrial fibrillation, revision

surgery due to haemorrhage, ventricular tachycardia, ventricular

fibrillation, prolonged intubation and mortality rates.

These discrepancies may have resulted from differences in the

definition of postoperative morbidity and postoperative serious

events, and in the duration of follow-up periods. Criteria used

to define the MS may also lead to discrepant results, namely,

cut-off points of criteria for the MS in various populations

or even parameters of the MS (waist circumference instead of

BMI) may vary. These differences may have a confounding effect

on assessing the association between pre-operative MS and

postoperative complications.

11,12

Inhibition of adipocytes is increased in obese people,

along with many proteins with immunomodulatory activity.

Thromboembolic events are more commonly seen in MS

patients undergoing CABG because a prothrombotic state

frequently occurs postoperatively.

Yılmaz

et al

suggested that

the MS might serve as a predictor of postoperative occlusion of

saphenous vein grafts after CABG. In our study, the incidences

of peri-operative myocardial infarction were similar between

patients with and without the MS. It is likely that peri-operative

myocardial infarction is not determined by early graft occlusion,

but rather by factors related to myocardial protection strategies

or unknown factors, which could explain the absence of a

significant difference between patients with and without the MS.

In the present study, lengths of hospitalisation and ICU

stay were significantly longer in the MS group. Brackbill

et al

showed that female patients with the MS undergoing CABG

surgery were at increased risk for longer postoperative stay as

well as for in-hospital death. Bardakcı

et al

reported that,

compared with the patients without the MS, those with the MS

had a significantly higher female-to-male ratio, and significantly

higher rates of family history of ischaemic heart disease, and

coronary artery occlusions involving the anterior descending

coronary, circumflex and right coronary arteries. This difference

could be noteworthy not only for increased morbidity rates, but

also for treatment costs.

Similar to previous studies,

11,12,17,20

no significant difference was

found in the occurrences of stroke and renal impairment after

CABG between the MS and non-MS groups (

0.05). However,

many parameters of morbidity, including AF, wound infection,

pulmonary complications, prolonged intubation, and lengths of

ICU and hospital stay were significantly higher in patients with

the MS (

0.01). Ardeshiri

et al

found that the MS represented

an increased risk for atelectasis and that patients with the MS

had a longer ICU stay following CABG. Özyazıcıo

et al

concluded that wound infection was significantly more frequent

in coronary artery disease patients with the MS than in those

without the MS (

0.05). In a multivariate analysis, the odds

ratios of postoperative stroke and renal failure in MS patients

were found to be 2.47 and 3.81, respectively.

The high prevalence of postoperative events in MS patients

may be associated with BMI and an increased incidence of

diabetes.

Bardakçı

et al

found significantly prolonged

intubation times, ICU and hospital stay, and a significantly

higher rate of pulmonary complications in MS patients; however,

in contrast with our study, they reported significant increases in

the rates of mortality and peri-operative myocardial infarction.

Moulton

et al

reported that obesity was not a risk factor

for adverse events after cardiac surgery, except for the increased

number of superficial surgical wound infections and a higher

incidence of atrial arrhythmias. Kopelman

et al

concluded

that thoracic and abdominal adipose tissue might be a cause of

ventilation and perfusion mismatch, which could induce a decline

in respiratory function by creating resistance to breathing exercises.

In our study, pulmonary complications were significantly

higher among patients with the MS (

0.01). This may be

explained by a negative effect of the MS on postoperative

respiratory function, leading to increased postoperative

pulmonary complications. Concerning the relationship between

pulmonary function and the MS, it was shown that male

adults with the MS had decreased vital capacity.

Bagheri

et al

indicated that BMI was not a predictor of mortality

after CABG, but pulmonary complications were independent

predictors of mortality in the postoperative period.

Cardiopulmonary bypass procedures are related to

inflammatory response and free radical accumulation.

It is known that MS patients have an ongoing, low-grade

inflammatory process, which can be exacerbated during surgery.

They also have increased systemic oxidative stress caused by

oxidative transformation of LDL-C.

The role of lipolytic

activity by abdominal fat storage has been emphasised in the

production of free fatty acids.

These free fatty acids exert a

significant pro-arrhythmic effect in ischaemic events. This effect

has been documented for ventricular arrhythmogenicity, but it