Effect of cardiopulmonary bypass on the development of acute kidney injury after open-heart surgery

Abstract

THE AIM. Assessment of factors associated with cardiopulmonary bypass (CPB) in acute renal dysfunction in patients in the early postoperative period after cardiac surgery. PATIENTS AND METHODS. Monocentric observational study in patients (n = 97) who underwent elective open-heart cardiac surgery (coronary artery bypass grafting -50.44 %, aortic valve prosthetics – 31.04 %, mitral valve prosthetics – 12.61 %) using cardiopulmonary bypass. Inclusion criteria: the study included patients not younger than 18 years old, undergoing cardiac surgery with CPB lasting up to 95 minutes (coronary bypass surgery, valve replacement), without signs of end-stage renal disease. Using nonparametric correlation analysis, we evaluated the effect on the development of acute kidney injury (AKI) of the following extracorporeal circulation factors: duration of CPB, aortic cross-clamp, mean arterial pressure (MAP), cardiac index (CI), perfusion flow rate (PFR), transport, consumption, and oxygen extraction variables. The diagnosis of AKI was made on the basis of the KDIGO classification, the studied parameters were recorded initially (before the operation), 15 minutes after the start of general anesthesia, 30 minutes after the start of cardiopulmonary bypass and 15 minutes after the end of general anesthesia. RESULTS. The frequency of AKI in 24 hours after surgery was 56.3 % (58 cases): including stage 1 in 37 (35.9 %), stage 2 in 17 (16.5 %) , stage 3 – in 4 (3.9 %) patients. In the 48th hour of the postoperative period, signs of AKI regressed and were presented in only 26 people (25.2 %), including the stage 1 in 18 (17.5 %), the stage 2 – in 5 (4.8 %), stage 3 – in 3 (2.9 %). Among the risk factors for AKI in cardiac surgery with CPB, the main effect of the anemia was revealed, especially a decrease in hemoglobin levels of less than 90 g / l and hematocrit of less than 25 %. CONCLUSION. Hemodilution below the "threshold" values of hemoglobin and hematocrit during the CPB provoke acute kidney injury in patients undergoing open-heart surgery.