Roje-Bedeković Marina, Bosnar-Puretić Marijana, Lovrencić-Huzjan Arijana, Demarin Vida
University Department of Neurology, Sestre milosrdnice University Hospital, Zagreb, Croatia.
Acta Clin Croat. 2010 Sep;49(3):267-74.
Hemodynamic features of the posterior circulation were evaluated by assessing visual evoked response in posterior cerebral artery (PCA) by means of functional transcranial Doppler (fTCD) in 49 patients with high-grade (70%-99%) internal carotid artery (ICA) stenosis or occlusion and 30 healthy subjects. Mean blood flow velocities (MBFV) and mean reaction time (time to peak velocities) (MRT) in each PCA were measured in the dark (closed eyes) and during white light stimulation (opened eyes, looking at the electric bulb), during three consecutive repetitive periods of 1 minute each. In the group of severe carotid disease patients, there was no difference in MRT in PCA during the white light stimulation (P=0.1), whereas in the dark MRT values showed a statistically significantly prolonged visual evoked response (P=0.02), but with no clinical relevance. MBFV values did not differ significantly during white light stimulation (P=0.1), whereas in the dark the difference was also statistically significant (P=0.03), but with no clinical relevance. On the contrary, in the group of healthy subjects, MRT values differed significantly both during white light stimulation (P=0.0005) and in the dark (P=0.00054), showing a significantly prolonged visual evoked response. During white light stimulation, MBFV showed significant decrease and prolonged vasoreactive response (P=0.004). Prolonged vasoreactive response in PCA in healthy subjects during repetitive measurements may indicate exhaustion of the vasoreactive mechanisms. In carotid disease patients, stable vasoreactive response may indicate that the compensatory mechanisms of the posterior circulation are always maximally engaged to compensate for carotid insufficiency.
通过功能性经颅多普勒（fTCD）评估49例颈内动脉（ICA）重度（70%-99%）狭窄或闭塞患者及30名健康受试者大脑后动脉（PCA）的视觉诱发电位，以评价后循环的血流动力学特征。在黑暗环境（闭眼）及白光刺激期间（睁眼，注视电灯泡），连续进行3个1分钟的重复时段，测量各PCA的平均血流速度（MBFV）和平均反应时间（达到峰值速度的时间）（MRT）。在重度颈动脉疾病患者组中，白光刺激期间PCA的MRT无差异（P=0.1），而在黑暗环境中MRT值显示视觉诱发电位有统计学显著延长（P=0.02），但无临床相关性。白光刺激期间MBFV值无显著差异（P=0.1），而在黑暗环境中差异也有统计学意义（P=0.03），但无临床相关性。相反，在健康受试者组中，白光刺激期间（P=0.0005）和黑暗环境中（P=0.00054）MRT值均有显著差异，显示视觉诱发电位显著延长。白光刺激期间，MBFV显著降低且血管反应性反应延长（P=0.004）。健康受试者在重复测量期间PCA的血管反应性反应延长可能表明血管反应机制耗竭。在颈动脉疾病患者中，稳定的血管反应性反应可能表明后循环的代偿机制始终最大程度地参与以代偿颈动脉供血不足。
