Cardiovascular Journal of Africa: Vol 26 No 1 (January/February 2015)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 26, No 1, January/February 2015

AFRICA

Overall, there was no significant difference between the

two groups with regard to occurrence of early neurological

outcomes (

2, 5.8% vs

1, 4.3%,

0.12) (Table 3). None

of the patients had revision for bleeding, cardiac tamponade, low

cardiac output syndrome, arrhythmia and systemic, respiratory

or wound infection. The length of intensive care unit stay and

hospital stay were similar between the two groups (Table 3).

Because of the limited sample size (34 vs 23 patients) and very

low occurrence rate of neurological events, the study power (1-

error) was quite low (

25%) in this study to provide evidence for

rejection of the null hypothesis. When significantly shorter mean

CPB time in group 2 than in group 1 patients (59.6

20.8 vs 72.3

21.9) was considered as a secondary outcome, our study had

71% power (1-

error) with an

error of 0.05 and an estimated

effect size of 0.60 (medium effect size).

Discussion

Our study showed that single-stage CEA and CABG is safe and

carotid intervention may be performed either before or after

initiation of CPB without adding much more complexity to the

procedure. However, because of the low effect size, which is a

direct measure of the occurrence rate of the outcomes, our study

could not draw a definitive conclusion regarding the protective

effect of hypothermia during CEA.

The decision whether each patient would receive CEA under

hypothermia or not was the surgeon’s discretion in general,

and this decision was not dependent on objective criteria.

However, it could not be totally neglected that the surgeon might

preferentially have intended to take the short CPB time into

consideration and performed CEA initially in the presence of

certain conditions or features, such as patient fragility or poor

coronary arterial structure. These features were not taken into

consideration as potential risk factors since patient records were

not standardised to provide objective information.

In addition, the majority of our patients were asymptomatic

of neurological complaints, which was another known risk factor

for the development of neurological events after simultaneous

CEA and CABG surgery. The operations were performed

within a period of seven years, in which the standard of surgical

approach did not undergo modification by the surgeon.

Similar to ours, in one earlier study where Di Tommaso

performed 73 combined CEA and CABG procedures, the

occurrence rate of temporary neurological deficits was quite low

(five patients), and an additional six patients had cerebrovascular

events during the late follow up. These authors attributed the

low rate of neurological complications to CPB-related benefits,

including haemodilution, pulsatile flow and hypothermia.

Yildirim

et al

used a similar technique for single-stage

operation and reported that four of 72 patients had neurological

complications and two of these became permanently disabled. In

a report on a small series of patients, neurological events occurred

in one of 15 patients undergoing combined CEA and CABG

under mild hypothermia.

Finally, Sadeghi

et al

reported no

early neurological outcomes and only one stroke during follow

up when CEA was performed under mild hypothermia.

Although all these studies have implied that hypothermia is

likely to have cerebral protective effects, our results and those of

others suggest that the lower complication rates may not only be

produced by the effect of hypothermia but may also be related

to the surgeons’ cumulative experience with the CEA technique.

Darling

et al

reported in their series of 420 patients that

the risk of stroke was 1.2% and mortality was 2.4% in patients

undergoing CEA prior to CABG. Another study showed that rate

of major stroke was 3.3%, whereas transient neurological deficit

rate was 9.9%

in 30 patients undergoing CEA before CABG.

Santos

et al

recommended a

30-day peri-operative period

between initial CEA and CABG. Although some authors

have

suggested that the indication for performing combined CEA and

CABG should be restricted to patients requiring urgent CABG,

we believe that a single-stage operation would often be the desired

option both for the surgeon and the patient, provided that there

would be no additional risks using a combined technique.

We are aware that our study had many limitations, including

retrospective design, lack of randomisation, single institution

experience and small sample size. Also, patients in this study

were not divided into treatment arms based on objective criteria,

a fact that may be a source of potential bias. Finally, follow-

up information was not sufficient to report since the majority

of patients could not respond to our invitation for follow up

because they lived in distant regions of the country.

Conclusions

Low rate of adverse neurological outcomes after simultaneous

CABG and CEA under CPB were previously attributed to

hypothermia by a possible mechanism of reducing neuronal

ischaemia. However, our study and previous ones showed that it

is difficult to establish such a relationship due to low occurrence

of adverse outcomes after combined operations. Single-stage

operation is effective and safe, and performing the CEA before

initiation of CPB may be considered when short duration of

CPB is required.

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