PREDICTORS OF POSTOPERATIVE ACUTE KIDNEY INJURY IN YOUNG ADULTS UNDERGOING CARDIAC SURGERY

Abstract

Acute kidney injury (AKI) is a frequent complication following cardiac surgery. The purpose of this study was to identify preoperative and perioperative predictors of AKI in young adult patients (≤ 60 years old) undergoing heart surgery. Between August 2010 and December 2013, 649 consecutive patients aged 60 or less underwent cardiac surgery. All patients were prospectively entered in an institutional computerized database. Of these, 601 (93%) received a median sternotomy and 48 (7%) had an alternative approach (thoracotomy, minithoracotomy or robotic interface). Serum creatinine levels were measured prior to surgery and every day following surgery, until hospital discharge. Acute kidney injury was defined according to the maximal change in serum creatinine level and was classified according to the RIFLE criteria into: ≥1.5-fold (risk), ≥2.0-fold (injury), and ≥3.0-fold (failure) increase in serum creatinine. The impact of preoperative and perioperative variables on postoperative AKI was assessed using a multivariate logistic regression model. Mean age was 51.1 ± 8.8 years and 134 patients (21%) were female. Isolated coronary artery bypass graft (CABG) surgery was performed in 303 patients (47%), isolated valvular surgery in 247 (38%), combined CABG and valvular surgery in 57 (9%) and another type of procedure in 42 (6%). Forty-three patients (7%) had undergone previous cardiac surgery. During the postoperative period, a total of 91 patients (14%) suffered from AKI, including 61 (9%), 16 (2%) and 14 (2%) who fell under the risk, injury and failure categories, respectively. On multivariate analysis, body mass index (BMI) [OR 1.11 [1.06-1.15]; p < .001], preoperative use of diuretics [OR 2.24 [1.28-3.94]; p = .005] and long duration of cardiopulmonary bypass (≥ 150 minutes) [OR 8.20 [3.32-20.3]; p < .001] were independent significant predictors of AKI (all severity classes). A higher value of last preoperative haemoglobin [OR 0.96 [0.95-0.98]; p < .001] was associated with lower rates of AKI. In patients aged 60 or less, long cardiopulmonary bypass times, preoperative use of diuretics and a high BMI are independently associated with an increased risk of AKI following cardiac surgery. High preoperative haemoglobin is independently associated with a decreased incidence of AKI.