Cardiovascular risk in patients with obstructive sleep apnea: Pathophysiology, epidemiology and management

Despite rising awareness of its high prevalence, myriad of health consequences andresponsiveness to treatment, obstructive sleep apnea (OSA) still remains underrecognizedand therefore untreated. One consequence of untreated OSA is cardiovasculardisease, which has been attributed to several purported mechanisms: increasedsympathetic drive, oxidative stress, inflammation, vascular endothelial dysfunction, largeintra - thoracic pressure fluctuations, mechanically - mediated vessel wall changes andmetabolic dysregulation. These mechanisms may be the basis for why OSA is morecommon among patients with hypertension, coronary artery disease, arrhythmias andstroke. Indeed, epidemiologic studies have provided evidence that untreated severe OSAconfers increased risk of cardiovascular events, but data are limited by small sample sizesand incomplete control for obesity (the major risk factor for OSA). Data from controlledtrials is scarce, but suggests that hypertension may improve with treatment of OSA,particularly in those with severe disease. The first - line treatment for OSA, continuouspositive airway pressure (CPAP), is safe and effective, and should be offered to patientswith severe OSA to reduce cardiovascular risk, and patients with mild to moderate apneaand known cardiovascular disease. Data from randomized intervention studies is needed to establish whether treatment of mild to moderate OSA improves cardiovascularoutcomes.