Materials and Methods
This prospectively planned study was conducted by including 80 patients with microalbuminuria who underwent coronary artery bypass surgery in our clinic between February 2019 and December 2020. For this study, ethical approval was given by the local Ethics Committee and all research was conducted in accordance with the Helsinki Declaration and its later amendments or comparable ethical standards. The aim of the study was clearly explained to all participants and their written informed consent was obtained.
In this study, the exclusion criteria were as follows: Preoperative chronic renal failure, preoperative dialysis, serum creatinine levels above 1.2mg/dl for males and 1.1mg/dl for females, underwent emergency surgery, active endocarditis, use of preoperative extracorporeal membrane oxygenator. Patients who had insulin medication more than one year were included in the group of having insulin medication while those who had been receiving insulin for less than one year, were not included.
Patients having insulin medication were using short-acting (regular insulin) and/or long-acting (NPH) or mixed insulin. Those taking oral antidiabetics were receiving metformin and/or stagliptin. The mean of HbA1c was 7.1% in the group using insulin, and 6.8% in the group receiving oral medication.
The records of the following risk factors were taken preoperatively: Age, gender, body mass index (BMI), hypertension, chronic obstructive pulmonary disease (COPD), smoking, whether they had an infarction in the last 28 days, presence of peripheral artery disease (PAD), ejection fractions, serum creatine and microalbuminuria levels in spot urine.
Albumin levels of 20-200 mg/L in spot urine were accepted as microalbuminuria(14). The patients were divided into two groups, namely as having insulin medication and taking oral antidiabetics. 42 patients were in the insulin medication group and 38 patients were in the oral antidiabetics medication group.
All operations were performed by the same surgical team, on-pump. Stockert S5 Roller Pump (Sorin Group) and Terumo FX oxygenators were used. Arterial cannula and single venous cannulation were applied from the aorta after median sternotomy. Body temperature was reduced to 32 degrees. Cardiac arrest was achieved with the help of hyperpotassemic isothermal blood cardioplegia. After the distal bypasses were made, the cross clamp was lifted and the proximal anestomoses were side clamped. pump outlet was inotrope, according to the need. In the diabetic patient group, blood glucose regulation was achieved with continuous crystallized insulin infusion.
Serum creatine levels on the postoperative 3rd day, duration of stay on the ventilator after surgery, amount of drainage, length of stay in intensive care unit (ICU), length of hospital stay, mediastinitis and mortality rates of the patients were recorded. It was found in previous publications that creatine levels increased 1-3 days after cardiac surgery(15), and we thought that we would obtain the most reliable results by recording creatine values on the 3rd day.