Abstract 4137895: Serum High-density Lipoprotein-Associated Paraoxonase-1 Levels Predict Recurrent Cardiovascular Events after Stent Implantation in Patients with Stable Angina Pectoris

Background: Poor clinical outcomes for patients undergoing hemodialysis (HD) after drug-eluting stent (DES) implantation have been reported. High-density lipoprotein (HDL) cholesterol is well-established as a negative risk factor for coronary artery disease, and its anti-oxidant property has been attributed mainly to the HDL-bound enzyme paraoxonase-1 (PON-1). Myeloperoxidase (MPO), a pro-oxidant enzyme released from activated neutrophils, has been shown to alter the atheroprotective function of HDL to a dysfunctional form. The aim of this study was to investigate the relationship between plasma MPO and serum PON-1 levels after implantation of DES in patients with stable angina pectoris (SAP) with and without HD. Methods: Serum PON-1 concentrations and PON-arylesterase activity were measured in 183 patients with SAP after DES implantation (HD group, n=37; non-HD group, n=146) with a sandwich ELISA method. Cardiovascular events were defined as sudden cardiac death, fatal or non-fatal myocardial infarction, cerebral infarction and other non-fatal events including unstable angina pectoris or coronary revascularization. Results: Serum PON-1 concentrations and PON-arylesterase activity were significantly lower in the HD group than in the non-HD group (PON-1 concentrations, P<0.0001; PON-arylesterase activity, P<0.0001). In addition, plasma MPO in patients undergoing HD were significantly higher than in patients not undergoing HD (P<0.0001). Moreover, plasma MPO showed a significant inverse correlation with serum PON-1 concentrations and PON-arylesterase activity (concentration: R= -0.24, P=0.0013; arylesterase-activity: R=-0.24, P=0.0014). Cardiovascular event rates were significantly higher in the HD group than in the non-HD group (67.6% vs. 43.8%, P<0.01). Kaplan-Meier survival analysis showed that the low-PON-1 group (<58.0 mg/mL, median) had a significantly worse outcome than the high-PON-1 group ( P =0.013). Multivariate analysis showed that a low serum PON-1 concentration was the only independent predictor of cardiovascular events (odds ratio, 1.93; 95% confidence interval, 1.10 to 3.40, P =0.024). Conclusions: These findings demonstrate that plasma MPO have a significant inverse correlation with PON-1 in patients undergoing HD and suggest that an imbalance between pro-oxidants and anti-oxidants may contribute to the progression and destabilization of human coronary atherosclerotic lesions in patients with SAP who undergo HD following DES implantation.