A Newly-Developed Method of Measuring Local Pulse Wave Velocity for Assessing of Severiy of Arteriosclerosis and Characteristics of Endotherial-Dependent Vasodilation

我们提出了一种局部测量脉搏波传播速度的新方法，用于定量评估动脉粥样硬化的严重程度。这种方法利用多普勒信号的复互相关，理论上有可能精确估计小于1毫秒的脉冲波的传播时间。利用同步双门脉冲多普勒法在动脉上的两个相邻位置检测因血流而移位的多普勒信号，将其存储在计算机中，然后进行互相关分析。最大相关输出的时间延迟给出了脉搏波的传播时间。脉搏波速度由两个换能器之间的距离与时间延迟之比来计算。在一项使用脉搏波的实验研究中。在流路模型中，无论采样距离和流速分布如何，计算得到的脉搏波速度波动都很小。实用的速度分辨率。这种方法的代表是e…更多的限制在2米/秒以下，这对于测量2厘米范围内的局部脉搏波速度(LPWV)来说是足够的精度。在一项健康志愿者的活体研究中，LPWV在股动脉(6.4±0.8m/s)比在颈动脉(4.8±0.5m/s)和腹主动脉(4.0±0.5m/s)快。该系统被用来评估：1.正常和高胆固醇血症兔腹主动脉的LPWV。2.L-NAME抑制NO合成及L-NAME和L-精氨酸促进NO合成条件下血管对乙酰胆碱的反应结果：(1)正常和高胆固醇血症兔腹主动脉LPWV从近端到远端递增。在相应区域，无论样本距离不同，高胆固醇血症兔的LPWV均高于正常兔。(2)L-NAME抑制乙酰胆碱(Ach)的血管松弛，L-精氨酸和L-NAME合用可恢复正常兔对乙酰胆碱(Ach)的松弛，L-NAME减弱对乙酰胆碱(Ach)的松弛，L-精氨酸和L-NAME轻度逆转高胆固醇血症兔对乙酰胆碱的松弛。(3)正常兔和高胆固醇血症兔在L-NAME或L-精氨酸和L-NAME联合作用下，血浆环鸟苷酸无明显变化。结论：该系统具有无创、操作简便、可检测LPWV改变等优点，值得用于局部血管病变的评估。

We propose a new method for local -measurement of the propagation velocity of a pulse wave for the quantitative evaluation of severity of atherosclerosis. This method uses a complex cross correlation of Doppler signals and, theoretically, has the potential for precise estimation of the propagation time of a pulse wave of less than 1 millisecond. Doppler signals shifted by blood flow are detected at two adjacent locations on the artery using the simultaneous two-gate pulsed Doppler method, stored in a computer, and then analyzed by cross correlation. Time delay at maximum correlation output gives propagation time of the pulse wave. The pulse wave velocity is calculated as the ratio between the distance separating the two transducers and the time delay. In an experimental study using a pulsatile. flow circuit model, regardless of sampling distance and flow velocity profile, there was little fluctuation in calculated pulse wave velocity. Practical velocity resolution. of this method was e … More stimated to be less than 2 m/sec, which is sufficient accuracy for measurement of local pulse wave velocity (LPWV) over a 2 cm distance. In a study in vivo of healthy volunteer, LPWV was faster in the femoral artery (6.4±0.8 m/sec) than in the carotid artery (4.8±0.5 m/sec) and abdominal aorta (4.0±0.5 m/sec).A new ultrasound system measuring LPWV has been developed, which can detect LPWV at 2 close points. The system is used to assess :1.LPWV foot-to-foot along abdominal aorta of normal and hypercholesterolemic rabbits. 2.Vascular responses to acetylcholine in conditions of inhibition of NO synthesis by L-NAME and augmentation of NO synthesis by L-NAME and L-arginine Results : (1)LPWV increases from proximal to distal along abdominal aorta of normal and hypercholesterolemic rabbits. In corresponding region, LPWV in hypercholesterolemic rabbits is higher than in normal ones, despite different sample distances. (2)L-NAME inhibits vascular relaxation to acetylcholine (Ach), Concurrent administration of L-arginine and L-NAME restores relaxation to Ach in normal rabbits, L-NAME attenuates relaxation to acetylcholine (Ach), L-arginine along with L-NAME slightly reverses relaxation to acetylcholine in hypercholesterolemic rabbits. (3)Plasma cyclic GMP is unchanged in situations of L-NAME alone or L-arginine plus L-NAME in normal and hypercholesterolemic rabbits. Conclusion : The new system is non-invasive and easy to be operated and can detect LPWV alterations, so it is worth being used to assess local vascular alteration Less