Lipoprotein-associated phospholipase A ₂ levels as a predictor of cardiovascular risks in patients with COPD and obstructive sleep apnea

Introduction: Lipoprotein-associated phospholipase A 2 (Lp-PLA 2 ) is an inflammatory mediator used as a novel marker for diagnosis of cardiovascular diseases and atherosclerosis in human. Both chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are associated with increased activation of inflammatory cells and molecular mechanisms associated with atherosclerosis. Aim: to study the relation between Lp-PLA 2 level and the clinical, polysomnographic and spirometric data in patients with OSA, COPD and overlap syndrome (COPD+OSA). Methods: Sixty patients were recruited, divided into 4 groups (15 in each group) based on their polysomnographic and spirometric data ; group I (normal), group II (OSA), group III (COPD) and group IV (overlap syndrome). Fasting serum samples were used to estimate lipid profile and Lp-PLA 2 concentrations. Results: apnea-hypopnea, arousal, desaturation indices, lipid profile and Lp-PLA 2 levels were significantly increased in all patients groups compared to control. The level of Lp-PLA 2 was significantly increased in overlap syndrome than OSA and COPD patients and was positively correlated with the severity of arousal in all patients groups. Conclusion: patients with overlap syndrome are more liable to cardiovascular disorders than either OSA or COPD alone and Lp-PLA 2 may be used as an independent predictor of cardiovascular disorders in patients with OSA, COPD and overlap syndrome.