Furtner Martin, Staudacher Martin, Frauscher Birgit, Brandauer Elisabeth, Esnaola y Rojas Maria M, Gschliesser Viola, Poewe Werner, Schmidauer Christoph, Ritsch-Marte Monika, Högl Birgit
Innsbruck Medical University, Department of Neurology, Anichstrasse 35, Innsbruck, Austria.
Sleep Med. 2009 Sep;10(8):875-81. doi: 10.1016/j.sleep.2008.09.011. Epub 2009 Feb 5.
OSAS has been associated with surrogate markers of atherosclerosis and is a known risk factor for stroke. However, there is limited data on the effects of recurring apneas in severe OSAS on cerebral circulation and their consequences on cerebrovascular reactivity and compliance.
To evaluate cerebral blood flow velocity (CBFV) changes and vascular compliance in patients with severe obstructive sleep apnea syndrome (OSAS) using transcranial Doppler sonography (TCD) and cerebral pulse transit time (PTT).
Seven patients (1 woman, 6 men, mean age 57.4 years) with severe OSAS underwent polysomnography at the sleep laboratory of the Neurology Department of Innsbruck Medical University. TCD was performed continuously during the whole night using a pulsed wave probe and was co-registered with routine polysomnography. Cerebrovascular reactivity was assessed by calculation of apnea and hypopnea-related CBFV changes. Arterial compliance was characterized by PTT derived from phase difference analysis between ECG and TCD signals. Sleep time was dichotomized into periods with high density of consecutive respiratory events (CRE) vs. periods with low density of consecutive respiratory events (non-CRE). TCD measurements of CBFV showed a regular, undulating pattern with flow minima immediately before apneas or hypopneas and maxima closely after their termination, reciprocally to peripheral O(2) saturation. CBFV reactivity was significantly diminished in CRE compared to non-CRE periods. PTT phase differences were reduced in non-CRE, and even more so in CRE periods, compared to initial wake phases.
We found severe disturbances of cerebrovascular reactivity in OSAS patients. Our data demonstrate loss of vasoreactivity and increase of arterial stiffness, indicated by CBF hyporeactivity and PTT reduction, especially during CRE periods. These changes are likely to impair cerebral circulation and may be detrimental to the endothelium.
阻塞性睡眠呼吸暂停综合征（OSAS）与动脉粥样硬化的替代标志物有关，是已知的中风危险因素。然而，关于严重OSAS中反复出现的呼吸暂停对脑循环的影响及其对脑血管反应性和顺应性的后果的数据有限。
使用经颅多普勒超声（TCD）和脑脉搏传输时间（PTT）评估重度阻塞性睡眠呼吸暂停综合征（OSAS）患者的脑血流速度（CBFV）变化和血管顺应性。
7例重度OSAS患者（1名女性，6名男性，平均年龄57.4岁）在因斯布鲁克医科大学神经科睡眠实验室进行多导睡眠监测。使用脉冲波探头在整个夜间连续进行TCD检查，并与常规多导睡眠监测同步记录。通过计算与呼吸暂停和呼吸不足相关的CBFV变化来评估脑血管反应性。动脉顺应性通过从心电图和TCD信号之间的相位差分析得出的PTT来表征。睡眠时间分为连续呼吸事件高密度期（CRE）和连续呼吸事件低密度期（非CRE）。CBFV的TCD测量显示出一种规则的、起伏的模式，在呼吸暂停或呼吸不足之前血流最小值，在其结束后紧接着出现最大值，与外周氧饱和度呈相反关系。与非CRE期相比，CRE期CBFV反应性显著降低。与初始清醒期相比，非CRE期PTT相位差减小，在CRE期甚至更小。
我们发现OSAS患者存在严重的脑血管反应性障碍。我们的数据表明血管反应性丧失和动脉僵硬度增加，表现为CBF反应性降低和PTT缩短，尤其是在CRE期。这些变化可能会损害脑循环，并可能对内皮细胞有害。
