Megat Razeem Abdul Razak
Obstructive sleep apnea (OSA), a breathing disorder that occurs during sleep, is characterized by a partial or complete blockage of the upper airway. Mild OSA has frequently been defined as AHI 5/h to less than 15/h based on polysomnography result. (AASM,1999). One estimate of mild OSA prevalence in the general population is 7.6% in men and 15% in women, respectively (Young T et al, 1993). However, whether mild OSA has significant cardiovascular complications is uncertain. Available evidence from population based longitudinal studies indicates that mild OSA is not associated with increased cardiovascular or all-cause mortality. There are no studies of the impact of treatment on cardiovascular mortality. There was no evidence from a single study that treatment of mild OSA reduces all-cause mortality. It is also not clear whether an association exists between mild OSA and the risk for developing atrial fibrillation and other cardiac arrhythmias. Furthermore, randomized clinical trials have failed to demonstrate a role for positive airway pressure (PAP) devices in reducing the risk of cardiovascular events. Therefore, interventions such as attempted weight loss, sleep position, sleep hygiene, will be considered part of usual care for mild OSA cases, and of course the comprehensive management of cardiovascular risk factors is more important due to the robust evidence and proven benefit. CPAP and other modalities such as a dental appliance or surgery should only be reserved for failed treatment in highly selected cases of mild symptomatic OSA.
Obstructive sleep apnea (OSA) is characterized by recurrent complete and partial upper airway obstructive events, resulting in intermittent hypoxemia, autonomic fluctuation, and sleep fragmentation. OSA prevalence is as high as 40% to 80% in patients with hypertension, heart failure, coronary artery disease, pulmonary hypertension, atrial fibrillation, and stroke. Mild OSA is defined as apnea hypopnea index (AHI) ≥5–15 episodes per hour. The third edition of the International Classification of Sleep Disorders by the American Academy of Sleep Medicine recommends continuous positive airway pressure (CPAP) treatment for the following conditions: (1) AHI > 5 with one or more symptoms (eg, sleepiness, fatigue, insomnia, snoring) or an associated medical or psychiatric disorder (eg, hypertension, coronary artery disease, atrial fibrillation) or (2) AHI > 15, irrespective of symptoms or associated conditions. Numerous treatment options are available for OSA. These include CPAP, auto CPAP, bilevel PAP, adaptive servo-ventilation, lifestyle intervention/medical weight loss, positional therapy, oral appliances, upper airway surgery, upper airway neurostimulation, and bariatric surgery. All patients with OSA should be considered for treatment, including behavioral modifications and weight loss as indicated. CPAP should be offered to patients with severe OSA, whereas oral appliances can be considered for those with mild to moderate OSA or for CPAP intolerant patients. In view of high prevalence of asymptomatic OSA, clinical implications of recommending against beneficial OSA treatment are far-reaching. There are also data that support benefits of CPAP treatment in the asymptomatic patient (eg, favorable impact on endothelial dysfunction assessed by flow-mediated dilatation). This talk provides perspective on treatment rationale of the asymptomatic patient with OSA and cardiovascular disease.