Abstract 197: A Novel Association Between High Density Lipoprotein Levels and the Risk of Postoperative Acute Kidney Injury

Abstract

Acute kidney injury (AKI) after cardiac surgery occurs in up to 30% of patients and is an independent predictor of death. HDL may attenuate mechanisms of AKI. We hypothesized that a high preoperative HDL cholesterol concentration is protective against postoperative AKI. We analyzed data from a prospective, 393-subject trial of perioperative atorvastatin to prevent post-cardiac surgery AKI. Statin-using patients were randomized to placebo or 80mg atorvastatin the morning of surgery and 40mg on postoperative day 1. Stain-naïve patients were randomized to placebo or 80mg the day prior to surgery and 40mg daily thereafter during hospitalization. The association between HDL level and maximum serum creatinine change from baseline in the first 48 postoperative hours was assessed using a two-component latent variable mixture model and AKI risk factors. Regression analyses assessed interactions of chronic statin use, perioperative atorvastatin treatment, and HDL level on AKI risk. Postoperative AKI occurred in 99 patients (25.2%). Median (10 th , 90 th percentile) preoperative HDL was 37.6 (25.0, 54.0) mg/dL and postoperative creatinine change 0.09 (-0.11, 0.59) mg/dL. Lower HDL levels were independently associated with increased creatinine rise (p=0.02) (Figure 1A). Regression analysis showed this association was present in statin-using but not statin-naïve patients (p=0.008) (1B). The protective effect of high HDL in chronic statin users was enhanced with perioperative atorvastatin treatment (p=0.004) (1C) and with increasing chronic statin dose (p=0.003) (1D). Similar analyses using LDL found no association with AKI risk (p=0.51). Conclusions: Higher preoperative HDL was associated with less risk of AKI. Statin exposure modified this association. Specifically, subjects with higher HDL levels on chronic statin therapy had less creatinine rise and appeared to further benefit from higher chronic statin dose and perioperative atorvastatin therapy.