Center for Vascular Evaluations and Center for Epidemiological Studies and Clinical Trials, Shanghai Key Laboratory of Vascular Biology, Shanghai Institute of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
Am J Hypertens. 2012 Mar;25(3):319-24. doi: 10.1038/ajh.2011.223. Epub 2011 Nov 24.
The brain is perfused at high-volume flow throughout systole and diastole. We explored the association of blood flow in the middle cerebral artery (MCA) with the pulsatile components of blood pressure in the systemic circulation and indices of arterial stiffness.
We enrolled 334 untreated subjects (mean age, 50.9 years; 45.4% women) who had been referred for ambulatory blood pressure monitoring to Ruijin Hospital, Shanghai, China. We measured the MCA pulsatility index (PI) by transcranial Doppler ultrasonography. The indices of arterial stiffness included pulse pressure (brachial (bPP) and central (cPP) measured at the office and 24-h ambulatory (24-h PP)) and carotid-femoral (cf-PWV) and brachial-ankle (ba-PWV) pulse wave velocity. Effect sizes, expressed per 1 s.d., were adjusted for sex, age, heart rate, and mean pressure.
Women had faster MCA blood flow than men (68.0 vs. 58.3 cm/s), but lower PI (75.4 vs. 82.3%; P < 0.001). The five arterial stiffness indices were intercorrelated (r ≥ 0.37; P < 0.001). PI increased (P ≤ 0.045) with bPP (+6.78%), cPP (+5.56%), 24-h PP (+7.58%), cf-PWV (+1.59%), and ba-PWV (+3.46%). In explaining PI variance, bPP ranked first (partial r(2) = 0.25), 24-h PP second (0.20) and cPP third (0.14). In models including both cf-PWV and ba-PWV, only the latter was significant (-0.19%; P = 0.84 vs. +3.54%; P < 0.001). In models including both bPP and ba-PWV, only the former contributed to PI variance (+6.98%; P < 0.001 vs. -0.24%; P = 0.78).
MCA blood flow is closely associated with the pulsatile pressure in the systemic circulation, which depends on arterial stiffness as measured by PWV.
大脑在整个收缩期和舒张期都以高容量流量灌注。我们探讨了大脑中动脉（MCA）的血流与全身循环中血压的脉动成分和动脉僵硬度的指标之间的关联。
我们纳入了 334 名未经治疗的患者（平均年龄 50.9 岁；45.4%为女性），这些患者因动态血压监测而被转诊至上海瑞金医院。我们通过经颅多普勒超声测量 MCA 搏动指数（PI）。动脉僵硬度的指标包括脉压（肱动脉（bPP）和中心（cPP），在办公室和 24 小时动态监测时测量）和颈股动脉（cf-PWV）和肱踝动脉（ba-PWV）脉搏波速度。表示为每 1 个标准差的效应大小，根据性别、年龄、心率和平均压进行了调整。
女性的 MCA 血流速度快于男性（68.0 比 58.3cm/s），但 PI 较低（75.4 比 82.3%；P<0.001）。五个动脉僵硬度指标相互关联（r≥0.37；P<0.001）。PI 随 bPP（增加 6.78%）、cPP（增加 5.56%）、24 小时 PP（增加 7.58%）、cf-PWV（增加 1.59%）和 ba-PWV（增加 3.46%）增加（P≤0.045）。在解释 PI 方差时，bPP 排名第一（偏相关系数（partial r(2)）为 0.25），24 小时 PP 排名第二（0.20），cPP 排名第三（0.14）。在包括 cf-PWV 和 ba-PWV 的模型中，只有后者具有统计学意义（-0.19%；P=0.84 比+3.54%；P<0.001）。在包括 bPP 和 ba-PWV 的模型中，只有前者对 PI 方差有贡献（增加 6.98%；P<0.001 比-0.24%；P=0.78）。
MCA 血流与全身循环中的脉动压力密切相关，而脉动压力取决于通过 PWV 测量的动脉僵硬度。
