Obstructive sleep apnea is an indicator of risk factors predisposing to cardiovascular diseases (i.e., hypertension, diabetes, obesity) and a marker of abnormal cardiac structure and function, and observational studies have also suggested that treatment of OSA by continuous positive airway pressure (CPAP) may improve the outcome of patients with OSA and established cardiovascular diseases 2. Similar to other diseases with failure of a “one size fits all” strategy such as heart failure with preserved ejection fraction (HFpEF) 4, a concept of different disease subtypes with different endotypes and phenotypes with different predominant pathophysiological features and therapeutic targets has been put forward 5. ...coronary artery disease is common in OSA and vice versa but the relative contribution of hypertension, diabetes, obesity, and OSA are hard to determine.