Medical Biodynamics Program, Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo , Brazil.
J Cereb Blood Flow Metab. 2023 Jun;43(6):989-998. doi: 10.1177/0271678X231153750. Epub 2023 Feb 1.
Dynamic cerebral autoregulation (dCA) in healthy young adults displays a daily variation. Whether the rhythm exists in patients with stroke is unknown. We studied 28 stroke patients (age: 26-83 years, 7 females) within 48 hours after thrombolysis. dCA was assessed 54 times in these patients during supine rest (twice in 26 and once in 2 patients): 9 assessments between 0-9AM, 12 between 9AM-2PM, 20 between 2-7PM, and 13 between 7PM-12AM. To estimate dCA, phase shifts between spontaneous oscillations of cerebral blood flow velocity (CBFV) in the middle cerebral artery and arterial blood pressure (BP) were obtained in four frequency bands: <0.05 Hz, 0.05-0.1 Hz, 0.1-0.2 Hz, and >0.2 Hz. CBFV-BP phase shifts at <0.05 Hz were significantly larger between 2-7PM, suggesting better dCA, than those at other times (p < 0.0001), and the daily rhythm was consistent for stroke and non-stroke sides. No significant rhythms were observed at higher frequencies (all p > 0.2). All results were independent of age, sex, stroke type and severity, and other cardiovascular conditions. dCA after stroke showed a daily rhythm, leading to a better regulation of CBFV at <0.05 Hz during the afternoon. The finding may have implications for daily activity management of stroke patients.
健康的年轻成年人的动态脑自动调节（dCA）显示出每日变化。患有中风的患者是否存在这种节律尚不清楚。我们在溶栓后 48 小时内研究了 28 名中风患者（年龄：26-83 岁，女性 7 名）。在这些患者仰卧休息期间，我们对 dCA 进行了 54 次评估（26 名患者进行了两次，2 名患者进行了一次）：9 次评估在 0-9AM 之间，12 次在 9AM-2PM 之间，20 次在 2-7PM 之间，13 次在 7PM-12AM 之间。为了估计 dCA，我们在四个频带中获得了大脑中动脉血流速度（CBFV）与动脉血压（BP）之间的自发波动之间的相位偏移：<0.05Hz、0.05-0.1Hz、0.1-0.2Hz 和 >0.2Hz。2-7PM 时，<0.05Hz 之间的 CBFV-BP 相位偏移明显大于其他时间（p<0.0001），并且这种节律对中风和非中风侧都是一致的。在较高频率下未观察到明显的节律（所有 p>0.2）。所有结果均独立于年龄、性别、中风类型和严重程度以及其他心血管状况。中风后 dCA 显示出每日节律，导致下午<0.05Hz 时 CBFV 的调节更好。这一发现可能对中风患者的日常活动管理具有重要意义。
