Increase in the Oxidized Low-density Lipoprotein Level by Sleep-Disordered Breathing and Correlation with Obesity in Patients with Heart Failure

Abstract

Sleep disordered breathing (SDB) is associated with increased mortality in heart failure (HF), but the underlying mechanism is not fully elucidated. Oxidative stress plays an essential role in the pathogenesis of HF. We investigated the association of SDB with oxidative stress in HF patients. Overnight polygraphy was performed in 71 patients with HF (ischemic cardiomyopathy n=17, dilated cardiomyopathy n=41, others n=13). Based on the presence of severe SDB, these patients were divided into two groups: Group A (apnea hypopnea index [AHI]≧ 30/h, n=17) and Group B (AHI<30/h, n=54). We measured plasma levels of malondialdehyde-modified low-density lipoprotein (MDA-LDL), one of the representative oxidized LDL. MDA-LDL levels were higher in Group A than Group B (136±56vs.102±34 U/L; p>0.05). Plasma levels of BNP, troponin T and CRP, and FABP were not different between two groups. Plasma MDA-LDL level were higher in patients with obese (BMI>25) than those without (141±51vs.101±36 U/L; p>0.005), but not associated with other cardiovascular risk factors, etiology of HF, cardiovascular medications, and other biomarkers. Multiple regression analysis showed that the most important determinants of log MDA-LDL level was obesity (β=0.39, p<0.005). SDB is associated with enhanced oxidative status, but obesity is the most important determinants of oxidative stress in HF. Weight reduction might be an important strategy to control oxidative stress in HF with SDB.