[The risk factors and prognosis of acute kidney injury after cardiac surgery: a prospective cohort study of 4007 cases].

ABSTRACT

OBJECTIVE: To investigate the risk factors and prognosis influential factors of acute kidney injury (AKI) after cardiac surgery. METHODS: The clinical data of patients who were hospitalized and underwent cardiac surgery from April 2009 to May 2011 were collected prospectively. Demographic characteristics, types of surgeries, preoperative renal function, pre- and intra-operative conditions and clinical outcomes, etc were recorded. RESULTS: A total of 4007 patients underwent cardiac surgery were recruited. The overall incidence of AKI was 31.2% (1250/4007). The incidence of AKI requiring renal replacement treatment (AKI-RRT) was 2.6% (104/4007). The overall hospital mortality was 1.9% (77/4007), and was significantly higher in AKI group than in non-AKI group (5.4% vs 0.3%, P < 0.01). The hospital mortality of AKI-RRT group was 36.5% (38/104). Grouped by type of surgery, cardiac transplantation had the highest AKI incidence (73.0%) and highest in-hospital mortality (18.9%), followed by coronary artery bypass grafting (CABG) combined with valve surgery (AKI incidence 57.8%, in-hospital mortality 6.1%) and aneurysm surgery (AKI incidence 52.0%, in-hospital mortality 5.5%). Multivariate logistic regression analysis showed that man, age, BMI, hypertension, chronic heart failure, pre-operative serum creatinine (SCr) > 106.0 µmol/L, intra-operative cardiopulmonary bypass time, intra-operative hypotension and aneurysm surgery were the risk factors of AKI after cardiac surgery. Multivariate logistic regression analysis showed that pre-operative SCr > 106.0 µmol/L and intra-operative hypotension were independent risk factors of renal recovery after cardiac surgery while recovery of urine output was the favorable factor. CONCLUSIONS: Cardiac surgery usually induces high AKI incidence and poor prognosis, which closely associated with many risk factors in peri-operative stage. The incidence of AKI is related to a number of perioperative risk factors. Heart transplantation, aneurysm surgery, CABG combined valve surgery are high risk surgeries.