Ando Shin-Ichi
Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan.
J Cardiol. 2018 Jul;72(1):10-18. doi: 10.1016/j.jjcc.2018.02.016. Epub 2018 Apr 4.
Sleep disordered breathing (SDB) has been recognized as one of the important causes or factors of worsening for various cerebro- and cardiovascular diseases. On the other hand, a recent large randomized study and meta-analysis about the effect of continuous positive airway pressure (CPAP) indicated no or only minor effects to improve the outcome of SDB patients. Accumulating evidence has indicated that the key factor of the link between SDB and cardiovascular diseases might be hypoxia caused during repetitive long apneic episodes. Hypertension and atrial fibrillation (AF) are two important cardiovascular diseases that relate to SDB and the therapeutic consequences by CPAP treatment have been studied. As for the mechanism that elevates blood pressure during night, stimulation of chemoreceptors by hypoxia and the resultant increase in sympathetic nervous activity is the first step and repetitive hypoxic stimulation changes the characteristics of chemoreceptors and baroreceptors resulting in daytime hypertension. Pathological changes in the atrial muscle in SDB patients might be a result of repetitive hypoxia and atrial expansion. As for triggering AF, several animal studies revealed that the changes in autonomic nervous system caused by hypoxia and negative intra-thoracic pressure might be crucial. However, a recent observational study could not show the relation between SDB and AF. The difference between the previous studies and this negative study seems to exist in the difference of the severity of SDB or the degree of hypoxia. Such a difference might be also one of the reasons why a recent randomized trial to prove the effect of CPAP in cardio- or cerebrovascular patients failed to improve the patient prognosis. Hence, in this review, the relationship between hypoxia and onset or continuation of hypertension and AF will be reconsidered to understand the fundamental and robust relationship between SDB and these cardiovascular diseases.
睡眠呼吸障碍（SDB）已被公认为是各种脑血管和心血管疾病病情恶化的重要原因或因素之一。另一方面，最近一项关于持续气道正压通气（CPAP）效果的大型随机研究和荟萃分析表明，其对改善SDB患者的病情没有效果或仅有轻微效果。越来越多的证据表明，SDB与心血管疾病之间联系的关键因素可能是反复长时间呼吸暂停发作期间引起的缺氧。高血压和心房颤动（AF）是与SDB相关的两种重要心血管疾病，并且已经对CPAP治疗的疗效进行了研究。至于夜间血压升高的机制，缺氧对化学感受器的刺激以及由此导致的交感神经活动增加是第一步，反复的低氧刺激会改变化学感受器和压力感受器的特性，从而导致白天高血压。SDB患者心房肌的病理变化可能是反复缺氧和心房扩张的结果。至于引发房颤，多项动物研究表明，缺氧和胸内负压引起的自主神经系统变化可能至关重要。然而，最近一项观察性研究未能显示SDB与房颤之间的关系。先前研究与这项阴性研究之间的差异似乎存在于SDB严重程度或缺氧程度的不同。这种差异可能也是最近一项旨在证明CPAP对心血管或脑血管疾病患者疗效的随机试验未能改善患者预后的原因之一。因此，在本综述中，将重新考虑缺氧与高血压和房颤的发病或持续之间的关系，以了解SDB与这些心血管疾病之间的基本和稳固关系。
