Abstract 176: Preoperative Small HDL Particle Concentration is Associated with Paraoxonase-1 activity and the Risk of Acute Kidney Injury After Cardiac Surgery

Abstract

Acute kidney injury (AKI) after cardiac surgery occurs in up to 30% of patients and predicts death. We have reported that a higher preoperative HDL particle concentration is independently associated with a decreased risk of AKI after cardiac surgery. HDL has known anti-oxidant properties that may attenuate AKI. We hypothesized that HDL particle size is associated with paraoxonase-1 (PON-1) activity and with the risk of AKI after cardiac surgery. We selected 90 patients who developed mild, moderate, severe, or no AKI from a prospective trial of perioperative atorvastatin to prevent post-cardiac surgery AKI. PON-1 paraoxonase activity was measured in apoB-depleted serum with fluorescent substrate 7-diethylphospho-6,8-dixuor-4-methylumbelliferyl. HDL particle size was assessed using the NMR Lipoprofile test. Linear regression was used to assess the association between preoperative small, medium, and large HDL particle concentrations and PON-1 activity. We assessed the association between HDL particle levels and the maximum serum creatinine change from baseline in the first 48 postoperative hours using two-component latent variable mixture models adjusted for AKI risk factors. A higher preoperative small HDL particle concentration was associated with a higher preoperative PON-1 activity (p=0.003, Figure 1A). Medium and large HDL particle concentrations were not associated with PON-1 activity. Small HDL particle concentration was found to be independently associated with postoperative serum creatinine change (p=0.02, Figure 1B), while medium and large HDL particle concentrations were not. Conclusions: A higher preoperative small HDL particle concentration was associated with a higher PON-1 activity and a decreased risk of AKI after cardiac surgery. Future work will characterize HDL throughout the surgical course to identify the mechanism underlying the protective association between HDL and AKI.