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

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.