Invastigation of postoperative renal injury in patients connected to a heart-lung machi̇ne duri̇ng open heart surgery

Introduction: Cardiac surgery-associated AKI is approximately 30% and is the second most common cause of AKI in postoperative period. AKI is associated with increased morbidity, mortality and hospital stay. The incidence of CSA-AKI varies according to the definition of AKI. The incidence of CSA-AKI is between 9% and 39% according to RIFLE and AKIN criteria. This ratio varies between 3.1% and 42% according to the KDIGO criteria that occurred in the last decade. In the etiopathogenesis of CSA-AKI; There are many factors such as exogenous and endogenous toxins, metabolic abnormalities, ischemia-reperfusion injury, neurohormonal activation, inflammation and oxidative stress. These etiological causes are often found in the perioperative period, not on their own, but at the same time, increasing the risk of damage. In addition, there are many factors that increase the risk of CSA-AKI associated with the patient in the preoperative period. Due to the limitations of urine output and serum creatinine for AKI detection, more sensitive parameters are needed. Although there are many indicators proposed for this purpose, the data on success rates are contradictory. In the literature, the markers reported to be more sensitive than other markers in the diagnosis of AKI are IL-18 and NGAL. The risk of CSA-AKI increases in patients with advanced age and comorbidity. More research is needed for the detection, prevention or management of AKI. Therefore, in our study; We aimed to provide a new interpretation of the contribution of intraoperative hemodynamic data to the postoperative acute kidney injury in patients who were connected to the heart-lung pump during open heart surgery and to determine the accuracy of some biomarkers which are thought to be the early marker of renal injury. Patients and Method: Between January 2018 and June 2018, 100 patients who were connected to the heart lung pump during open heart surgery in Akdeniz University Faculty of Medicine Hospital were included in the study with being over 18 and without gender discrimination. 29 of the patients included in the study were female and 71 had male sex. Preoperative demographic data and associated with kidney damage the risk factors mentioned in the literature are recorded. Hemodynamic data, transfusion rates, urine volume and intraoperative blood gas parameters were recorded in the intraoperative period. Laboratory parameters and urine output of the patients were monitored until the 7th day after the operation. In addition, preoperative and postoperative 3rd hour blood samples were used to measure the cystatin C, IL-18 and NGAL parameters which are thought to be the early markers of renal injury. The statistical analyzes of the study were analyzed by Akdeniz University Statistical Advisory Unit using IBM SPSS Statistics 18 © Copyright SPSS Inc.1989, 2010 software and GraphPad Prism 5 software. Results: The mean age of the patients was 64.52±3.42 years and mean BMI values were 27.1±4.3 kg/m2. According to the KDIGO criteria, AKI developed in 24 patients. 18 of these patients had stage 1, 2 had stage 2 and 4 had stage 3 AKI. In comparison of demographic data of these patients, serum creatinine levels above 1.2 mg /dl were found to be risk factors for AKI development in the preoperative period. Other existing comorbidities did not contribute to AKI development. In 13 of the patients (26%) who underwent isolated CABG (n=50), 4 of the patients (22%) who underwent valve replacement (n=18), 3 of the patients (42%) who underwent valve + CABG (n=7), and 4 of the patients (23,5%) who underwent LVAD surgery (n=21), developed AKI. No significant difference was found in the statistical analysis of AKI development risk according to the type of surgery of the patients. The last opaque substance exposure period before the operation was observed as an average of 32±7.7 days in the AKI group and 25.9±2.7 days in the group without AKI. The duration of exposure to opaque substances was found to be outside the risky period for both groups. Hemodynamic data were found to be higher than the lower limits in the literature for the development of kidney damage, no statistically significant difference was observed in both groups. The mean duration of CPB in the AKI group was 133±12 minutes, and the mean time was 107.8±5.3 minutes in the group without AKI. There was no statistically significant difference in cross-clamping time. There was no statistically significant difference between the two groups in terms of decrease in hemoglobin and hematocrit values due to hemodilution. In addition, patients in both groups were found to have a DO2 value above 262 ml/min/m2, which was measured at baseline before and after confinement to CPB. In patients with AKI, it was observed that the changes in blood glucose levels between the beginning and the end of the operation were larger than those without AKI. More blood / blood product transfusion was seen in the AKI group and no difference was observed in the amount of urine produced in the intraoperative period. Of the 24 patients who developed AKI, 13 had postoperative complications. Postoperative complications were observed in 8 of 76 patients without AKI. In the preoperative and postoperative 3rd hour measurements of biomarkers evaluated in our study for the early detection of AKI, Cystatin C was found to be unsuccessful in detecting AKI. The IL-18 and NGAL parameters were found to be approximately 100% increased in the postoperative 3rd hour in the group with AKI, and were found to be statistically successful in AKI detection. Conclusion: The risk of CSA-AKI increases in patients with advanced age and comorbidity. Although there is a better understanding of the pathophysiology of CSA-AKI, the more sensitive algorithms to diagnose AKI, and the more sensitive laboratory parameters in detecting renal damage; There are very small improvements in the detection, prevention or management of CSA-AKI. Preoperative and postoperative 3rd levels of plasma levels of Sistatin C, NGAL and IL-18 were investigated for early detection of renal damage; No statistically significant difference was found between cystatin C levels in terms of AKI development risk. Among the preoperative and postoperative 3rd hour measurements of NGAL and IL-18, a statistically significant difference was observed in patients with AKI. It is clear that there is a need for studies with larger case series to determine the causes of acute kidney injury and to test the accuracy of markers used for early kidney injury. We believe that if these markers are more economical, they will provide routine use in the clinic as well as preoperative predictive value and contribute to the reduction of cases with cardiac surgery-related AKI with the presence of new markers in the future.