Diabetic patients are prone to complications
after CABG surgery, and a special interest and
implementations are required during the perioperative
period. Diabetic CABG patients are at an increased
risk for cerebrovascular disease, AKI, sternal
infections, and mortality and require transfusions
more often.[
12] Diabetes mellitus is an independent
risk factor for AKI, even when blood transfusions are
not considered. Endothelial dysfunction and impaired
microcirculation are considered to be responsible for its
pathogenesis.[
12,
13]
Several factors have been found to be associated
with increased blood transfusion. According to
Klein et al.,[14] age, sex, body surface area, logistic
EuroSCORE, preoperative hemoglobin and creatinine
were associated with increased blood transfusion.
Blood transfusions are a specific topic that may
complicate and lead to AKI in CABG patients and
requires a rigorous approach.[15] Cardiovascular
surgeons tend to avoid redundant blood transfusions,
and studies defining the safe limits for blood transfusion
have been previously published.[16] Restrictive or liberal
thresholds for RBC transfusions were investigated
by Mazer et al.[17] The transfusion criteria were
defined as a hemoglobin level of <7.5 mg/dL for the
restrictive threshold approach and a hemoglobin level
of <9.5 mg/dL for the liberal threshold approach.
The study showed the restrictive threshold approach
to not be inferior to the liberal threshold approach
with respect to mortality, infection, neurological
complications, pulmonary impairment, and AKI. The
six-month follow-up results of the study also supported
the initial results.[18]
Lower body mass index, higher logistic
EuroSCORE II, and lower preoperative platelet
counts in our cohort were found to be associated with
Stage 1 AKI. Receiving blood transfusion during the
perioperative period was also found to be associated with a higher incidence of Stage 1 AKI in terms of
RBC, FFP, platelet, and complete transfusions.
In their propensity score-matched retrospective
study, Kocyigit et al.[19] found receiving blood
transfusion not to be associated with new-onset
dialysis or discharge creatinine level in diabetic CABG
patients. The Koster et al.’s[20,21] studies also found
no significant association between blood transfusion
and renal impairment in terms of RBC and apheresis
platelet concentrates. However, according to Amini et
al.,[22] AKI was associated with RBC transfusions and
diabetes, in addition to advanced age, on-pump cardiac
surgery, and prolonged mechanical ventilation.
Although blood transfusions have been shown to
be associated with negative outcomes, postoperative
anemia after CABG surgery is also related to the
increased morbidity.[23] To maintain vital functions at
the cellular level and avoid anemia induced hypoxia,
keeping hemoglobin levels within the safe range, while
avoiding unnecessary blood transfusions is essential.
The use of erythropoietin, oral or intravenous
iron replacement, and a predeposit autologous
donation may help prevent blood transfusions in the
preoperative period. During the intraoperative and
early postoperative periods, the use of tranexamic acid
and cell salvage may be beneficial. Minimal invasive
approaches including thoracoscopic, robotic-assisted,
or transcatheter techniques are applicable. Endoscopic
harvesting of the saphenous vein may also have
relevance.[24-26]
Our study presents the results from a limited
number of patients. This is the main limitation of
the study. The Stage 1 AKI-positive group had a low
number of patients; as such, propensity score-matching
may not be applicable. Variables that may affect renal
impairment such as how many years the patient has
been diagnosed as diabetic, their insulin use and
dosage amounts, glycated hemoglobin (HbA1c) levels,
drainage amounts, use of inotropic agents, and presence
of an intra-aortic balloon pump were not studied. This
is another limitation of our study. The retrospective
design of the study is the third limitation. However, a
sample of patients from a single cardiac center provides
similar surgical and anesthetic management for the
entire study group, which relatively strengthens the
results of our study.
In conclusion, our study results suggest that
perioperative RBC, FFP, platelet, and complete transfusions are associated with postoperative AKI
among diabetic CABG patients. Further large-scale,
prospective, randomized-controlled studies are needed
to gain a better understanding of blood transfusionassociated
AKI in this population.
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.
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