As one of the most common operations,
particularly after the introduction of CBP machine,
CABG surgery is subject to much interest, as it
may lead to prolonged weaning times, increased
renal dysfunction, stroke, deep sternal infections,
and death.[
6] These results are thought to be related
to systemic inflammation, which is most probably
caused by CBP machines.[
7,
8] Nevertheless, systemic
inflammation which occurs after CABG procedures is affected by many factors other than CPB machines.
Tissue damage, endotoxemia, and contact of blood
with non-endothelial surfaces are the main known
triggers of SIRS.[
9,
10]
There are two major ways to investigate SIRS
both in cardiac surgery and other fields. One is
through the use of laboratory parameters such as tumor
necrosis factor or interleukins. The other way is with
clinical criteria such as hypotension, hyperthermia,
leukocytosis.[5,11] Unfortunately, according to the
global studies, the number of patients who develop
SIRS after cardiac surgery cannot be neglected. In
the study of Sasse et al.,[12] the postoperative SIRS
ratio was 39% among the patients undergoing cardiac
surgery, including pediatric cases. In another study,
MacCallum et al.[13] reported that the postoperative
SIRS ratio was 96.2% using clinical parameters for
patients in an adult cardiothoracic ICU.[13] We used
the same method in our study and the postoperative
SIRS ratio was found to be 83.9%.
Although previous studies have investigated the
risk factors of SIRS in many settings, only a few
have evaluated the risk factors of SIRS after CABG
procedures. However, as a major factor affecting
postoperative outcomes of patients undergoing
CABG, many studies regarding the causes of SIRS
and related precautions for its avoidance SIRS are
expected. One of these studies was by Ferraris et al.,[14]
which revealed a relation between the intraoperative
blood use and SIRS. According to their study,
intraoperative blood use led to negative changes
in the immune system and induced SIRS. The
authors also reported that other factors which caused
SIRS were low preoperative functional capacity, liver
dysfunction, chronic obstructive pulmonary disease,
male sex, preoperative steroid therapy, preoperative
dialysis history, and age above 74 years. In another
study, Sinning et al.[15] investigated the postoperative
effects of SIRS on patients undergoing transaortic
valve implantation. Their results showed that risk
factors for SIRS were the amount of contrast agents
used, major bleeding, major vascular trauma, and
blood transfusion. In a similar study by Lindmann
et al.,[16] 747 patients who underwent aortic valve
implantation or transaortic valve implantation were
included to investigate the relationship between
SIRS and mortality. The authors found that the
predictors of SIRS were high preoperative hemoglobin
and leucocyte count, cerebrovascular disease,
and preoperative dialysis history. Another study examining SIRS in pediatric patients undergoing
cardiac surgery in the postoperative period revealed
that predictors of SIRS were age, low weight, CPB
time, and cross-clamp time.[9] In a study by Güvener
et al.,[17] 246 pediatric patients were retrospectively
evaluated to identify the effects of SIRS on the
postoperative results. The study revealed that
predictors of SIRS were CPB time, low weight
(<10 kg), and right-to-left shunt before surgery.
In the present study, preoperative EuroSCORE,
on-pump CABG, and IABP use were found to be
SIRS predictors. In contrary to aforementioned
studies, CPB time was not found to be among the
SIRS predictors. Another factor different from other
studies was hemoglobin level, as such we found that
low hemoglobin levels, but not high hemoglobin
levels, were the predictor of SIRS.
Although it is well-known that SIRS is one of
the main reasons for adverse postoperative outcomes
after cardiac interventions, only a few studies have
addressed into this problem. In one of these studies
made by Sinning et al.,[15] 152 patients who underwent
transcatheter aortic valve implantation (TAVI) were
evaluated to question the effects of SIRS on the
postoperative results. According to this study, SIRS
affected early postoperative results and postoperative
first-year mortality rates; however, it had no effect on
postoperative stroke. Güvener et al.[17] also evaluated
the effects of SIRS on postoperative results of pediatric
cardiac operations and SIRS was found to be a strong
predictor of postoperative mortality. As mentioned
above, Lindmann et al.[16] evaluated 747 patients
undergoing postoperative TAVI in terms of SIRS
predictors. Clinical parameters were used in their
study and the patients with SIRS had a longer ICU
length of stay, more frequent ICU admission, longer
hospitalization period, and higher acute renal failure
incidence. The authors also found that SIRS had no
significant effect on postoperative stroke and mortality
in the early postoperative period. Subgroup analysis
revealed that SIRS was a predictor of mortality in
cardiac patients with diabetes in the postoperative
period. In another study, Soares et al.[9] evaluated
101 patients who underwent open heart surgery.
It was shown that SIRS prolonged the weaning
period and the length of ICU and hospital stay. The
authors also reported that SIRS had no significant
effect on mortality. Our results are consistent with
previous studies. According to the present study,
SIRS prolonged the weaning period and the length of ICU stay; however, it did not increase neurological
outcomes or mortality.
The main limitations of the present study are its
retrospective design and the evaluation of clinical
parameters only, but not proinflammatory markers.
Nevertheless, our study is one of the rare studies
which address into the relationship between SIRS and
CABG.
In conclusion, the relationship between SIRS
and CABG outcomes is still an obscure subject to be
elucidated. In our study, mean age and EuroSCORE
were higher and preoperative hemoglobin levels were
lower in patients with SIRS. On-pump surgery and
IABP use were also significantly higher in the SIRS
group, while the length of ICU stay and the weaning
period were significantly longer in the SIRS group.
Based on these results, we can speculate that age
is the only factor which has a significant effect on
SIRS prediction. Although SIRS seems not to have
an evident effect on neurological complications or
mortality, it may prolong the length of ICU stay and
the weaning period. Further prospective, large-scale,
randomized-controlled studies are needed to confirm
these findings.
Declaration of conflicting interests
The authors declared no conflicts of interest with respect
to the authorship and/or publication of this article.
Funding
The authors received no financial support for the research
and/or authorship of this article.