الفهرس 
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Abstract
SUMMARY
cute kidney injury is a frequent complication after cardiac
surgery. According to the literature and the various
definitions of acute kidney injury, cardiac surgery associated
kidney injury may concern 1% to 30%of the patients. Mortality
raises from 1% up to 50% for patients who undergo renal
replacement therapy following cardiac surgery.
Early detection of renal dysfunction is often presented as
a ―holy grail‖ because it could allow interventions (both
diagnostic and therapeutic) to prevent evolution to renal failure.
Serum creatinine reflects the balance between the synthesis
of creatinine and its excretion by the kidney. Creatinine
production in the body varies with muscle mass, physical activity,
protein intake, and catabolism while creatinine excretion is
dependent on the glomerular filtration rate (GFR). The serum
creatinine and GFR are inversely and exponentially related.
Halving of GFR implies that there will be doubling of creatinine
concentration. There are several limitations for creatinine as a
marker of kidney injury in acute perioperative situations.
However, it has a poor, predictive accuracy for kidney injury,
particularly in the early stages of AKI.
Currently the early prediction of AKI by clinical and
laboratory methods remains difficult. In clinical practice
creatinine level and urine output are the most frequently used
indicators of renal dysfunction despite their limited sensitivity
and specificity.
A
Summary
79
Several urinary proteins such as neutrophil gelatinaseassociated
lipocalin (NGAL), cystatin C, kidney injury
molecule-1 (KIM-1) and interleukin-18 (IL-18) have been
studied to assess their role as early biomarkers of AKI in
patients undergoing cardiac surgery.
Hemoglobin A1c (HbA1c) is widely used as a marker of
average blood glucose concentrations over the preceding 2 to 3
months and it has advantages over glucose tests. Some evidence
indicates that high HbA1c levels prior to surgery are strongly
associated with the severity of adverse events after CABG.
HbA1c levels were found to be related to cardiovascular
and renal complications following open heart surgery. Multiple
factors have been implicated as contributors to postoperative
AKI, including advanced age, female gender, presence of
diabetes mellitus, chronic kidney disease, extended time
between heart catheterization and surgery, aortic cross clamp
time, duration of cardiopulmonary bypass (CPB), and blood
transfusion following surgery.
In this study we measured both HbA1c, serum creatinine,
UOP and urinary neutrophil gelatinase associated lipocalin
(NGAL) to predict acute kidney injury in patients undergoing
elective CABG.
Summary
80
After obtaining the approval of our institute, Hospitals
ethical committee, informed consent was taken from 40 patients
of ASA physical status II - III, aged 50-80 years, scheduled to
undergo isolated coronary artery bypass grafting (CABG) in
this prospective cohort study at Ain-Shams University
Hospitals, from June 2019 until July 2020.
This study was done as a prospective cohort study, in
which 40 patients were divided into 2 equal groups who
underwent isolated coronary artery bypass grafting (CABG).
Patients with preoperative HbA1c 5.7-6.4% (group A)
(prediabetics).
Patients with preoperative HbA1c > or = 6.5% (group B)
(diabetics).
Primary Outcome:
Acute kidney injury (AKI); diagnosis of postoperative
AKI was made in accordance with the International Kidney
Disease: Improving Global Outcomes (KDIGO) definition of
AKI KDIGO Classification (Khwaja, 2012). AKI is defined as
any of the following: increase in serum creatinine by ≥0.3
mg/dl within 48 hours of surgery or increase in serum
creatinine to ≥1.5 times baseline within 3 days of cardiac
surgery.
Summary
81
Normal range of BUN, Cre, is accepted as 18-55 mg/dL,
0.7-1.2 mg/dl, respectively. Cut-off level for urinary NGAL 12
hours post- bypass is accepted as 65 ng/mL to determine
postoperative AKI.
The study revealed that:
AKI following cardiac surgery causes multiple
postoperative complications and leads to prolonged
hospitalization, increased costs, and eventually increased
mortality rates. This study revealed that elevated preoperative
HbA1c level increase incidence of post CABG acute kidney
injury along with length of postoperative ICU stay.