In this study, a high preoperative NLR and low
preoperative PNR were evaluated as risk factors for
the development of new-onset POAF in patients
undergoing CABG. On the other hand, lymphocyte
counts, and the ACEI/ARB use were higher in the
patients who were in normal sinus rhythm.
The most common arrhythmia after CABG
is AF and POAF can be seen in 15 to 40% of
cases following isolated CABG.[1] Atrial fibrillation
can cause complications such as heart failure,
thromboembolism, cerebrovascular occlusive events,
and renal insufficiency. Also, it is one of the leading
causes of mortality after CABG itself and, due
to morbidities caused by AF, many patients have
prolonged hospital stays and prolonged hospitalization
increases the cost per patient.[11] New-onset POAF is
associated with many factors such as age, male sex,
DM, HT, recent MI, heart failure, obesity, and left
atrial size.[1,10] In our study, although age and BMI measurements were found to be higher in the POAF
group, no statistically significant difference was found
between those with and without POAF.
The relationship between AF following after
cardiac surgery and preoperative inflammatory
markers has been evaluated in many studies and
demonstrated by inflammatory cell infiltration and
interstitial fibrosis observed in the atrial tissues of
patients developing AF. The link between oxidative
stress following after cardiac surgery, complex
inflammatory response.[12,13] caused by the effect of
cellular inflammation, interleukin 6 and 8, increased
WBC count, CRP levels, and AF development has
been previously shown.[14-16] In our study, although
WBC counts were found to be higher in the patient
group who developed POAF, it was not statistically
significant. In addition, there was no significant
difference in the CRP levels in the patients with or
without POAF.
The WBC count and its subtypes have been found
to be markers of inflammation in various cardiovascular
diseases.[4] Neutrophils represent activated non-specific
inflammation.[4] In addition, neutrophil activation
during CPB causes perioperative myocardial damage
and, subsequently, reperfusion injury.[4,17,18] Decreased
lymphocytes are associated with poorer general
health, increased physiological stress, and depressed
immune response.[4] Platelets play an important role
in inflammation and thrombosis by secreting various
mediators.[6] Therefore, we examined WBC subtypes
in our study. We found lower lymphocyte counts in
the patients with POAF compared to those without
POAF (p=0.043). However, we found no significant
difference in the neutrophil, platelet, and basophil
counts between the groups. In recent years, the NLR,
PLR, and non-specific inflammatory response have
been associated in many studies based on the increase
in neutrophil and platelet counts and a decrease in the
lymphocyte counts.[7-11,19-22]
Correlation studies between NLR and development
of AF conducted by Gibson et al.[9] showed that the
rate of AF development was higher in patients with
a high NLR value, which is used as an inflammatory
marker.[4,23] Also, in this study, preoperative NLR
was independently associated with POAF with 75%
sensitivity and 53% specificity.
A limited number of studies is available in the
literature reporting the association between PLR
and POAF after CABG surgery. Gungor et al.[10] found a higher risk of developing POAF in patients
with higher preoperative PLR. Later, this result was
supported by similar studies.[24,25] In our study, we
found a higher preoperative PLR in the patients with
POAF. However, we found no statistically significant
difference in the preoperative PLR values in the
patients who did not develop POAF (p=0.315).
To the best of our knowledge, this is the first
study to evaluate PNR for inflammation and AF
predictability in the literature. In our study, the PNR
was found to be a significantly lower predictor for
POAF, although no significant results were found in
the ROC analysis (AUC: 0.575, p=0.244). We believe
that low PNR in patients who develop POAF can
yield significant results in predicting the development
of POAF. However, further large-scale studies are
needed to confirm this hypothesis.
Although ACEI and ARB inhibit the reninangiotensin
system by targeting different sites in
the pathway, clinical studies have shown that both
drugs effectively lower blood pressure and reduce
cardiovascular events.[26,27] They can modify atrial
substrate, prevent inflammation and, thus, reduce
the risk of AF.[28,29] A growing number of evidence
suggests that ACEI and ARB can be used for AF
prevention.[30,31] In our study, we found that ACEI/ARB
use was protective against POAF development in the
preoperative period in addition to NLR and PNR
(OR=0.335).
The limitations of this study include its relatively
small sample size, retrospective design, and relatively
short follow-up period. Asymptomatic, short-term
POAF episodes or new-onset POAF within the first
month of control visit following discharge may not
have been identified.
In conclusion, unlike many other inflammatory
markers and bioassay, the PNR, NLR, and PLR are
simple, inexpensive, and routinely reported tests as a
part of complete blood count. In this study, we found
an independent correlation between baseline NLR and
POAF after CABG surgery. In addition, when studied
in larger cohorts, the decrease in the PNR in patients
who develop POAF can yield significant results in
predicting the development of POAF and can be used
as a marker. Nonetheless, further, large-scale, longterm,
prospective studies using PNR, NLR, and PLR
are required to evaluate long-term outcomes of POAF
after CABG surgery.
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.