Evaluation of Acute Kidney Injury in Postcardiotomy Cardiogenic Shock Patients Supported by Extracorporeal Membrane Oxygenation

Background: This study sought to evaluate the incidence of acute kidney injury (AKI) defined by the Kidney Disease: Improving Global Outcomes (KDIGO) group in patients supported by veno-arterial extracorporeal membrane oxygenation (VA ECMO) after post-cardiotomy cardiogenic shock (PCS), and to identify the risk factors for AKI >3. Methods: Patients with and without AKI >3 were divided into two groups. Potential risk factors for developing AKI >3 were evaluated by univariate logistic regression analysis. Patient risk factors (p < 0.1) in the univariate analysis were entered into the multivariable logistic regression model. The tolerance and variance inflation factors (VIF) were calculated to evaluate the collinearity of the potential variables. Results: 136 patients with a mean age of 53.6 +/- 13.9 years (66.9% male) were enrolled in the study. 80 patients (58.8%) developed AKI >3. Patients with AKI >3 required significantly longer mechanical ventilation (200.9 [128.0, 534.8] hours vs. 78.9 [13.0, 233.0] hours, p < 0.001). The ICU stay and hospital stay of patients with AKI >3 were much longer than patients with AKI <3 (384 [182, 648] hours vs. 216 [48, 456] hours, p = 0.001; 25.0 [15.3, 46.6] days vs. 13.4 [7.4, 38.4] days, p = 0.022, respectively). There was no difference in preoperative risk factors between the two groups. Age, cross-clamp time, cardiopulmonary bypass (CPB) time, the timing of ECMO implantation, mean artery pressure (MAP), lactate concentration before ECMO, and preoperative ejection fraction (EF) were entered into the multivariable analysis. The timing of ECMO implantation was an independent risk factor for AKI >3 (p = 0.036). Intraoperatively implantation of ECMO may decrease the incidence of AKI >3 (odds ratio (OR) = 0.298, 95% confidence interval (CI) = 0.096-0.925). The tolerance and variance inflation factors showed that there was no collinearity among these variables. Conclusions: The incidence of AKI >3 in patients supported by VA ECMO after PCS was 58.8% in our center. Patients with AKI >3 required significantly longer mechanical ventilation and hospital stay. Intraoperative implantation VA ECMO was associated with a decreased incidence of AKI >3.