Manning Timothy S, Shykoff Barbara E, Izzo Joseph L
Division of Clinical Pharmacology, Department of Medicine, State University of New York at Buffalo, NY, USA.
Hypertension. 2002 May;39(5):963-8. doi: 10.1161/01.hyp.0000016920.96457.7c.
The present study assessed (1) the impact of the measurement site (lower versus upper extremity) on the corresponding compliance variables and (2) the overall reliability of diastolic pulse contour (Windkessel-derived) analysis in normal and hypertensive subjects. Arterial tonograms were recorded in the supine position from the radial and posterior tibial arteries in 20 normotensive (116+/-12/68+/-8 mm Hg) and 27 essential hypertensive subjects (160+/-16/94+/-14 mm Hg). Ensemble-averaged data for each subject were fitted to a first-order lumped-parameter model (basic Windkessel) to compute whole-body arterial compliance (C(A)) and to a third-order lumped-parameter model (modified Windkessel) to compute proximal compliance (C(1)) and distal compliance (C(2)). Despite high-fidelity waveforms in each subject, the first-order Windkessel model did not yield interpretable (positive) values for C(A) in 50% of normotensives and 41% of hypertensives, whereas the third-order model failed to yield interpretable C(1) or C(2) results in 15% of normotensives and 41% of hypertensives. No between-site correlations were found for the first-order time constant, 2 of the 3 third-order model curve-fitting constants, or C(A), C(1), or C(2) (P>0.50). Mean values for all 3 compliance variables were higher for the leg than the arm (P<0.05 each). We conclude that differences in Windkessel-derived compliance values in the arm and leg invalidate whole-body model assumptions and suggest a strong influence of regional circulatory properties. The validity and utility of Windkessel-derived variables is further diminished by the absence of between-site correlations and the common occurrence of uninterpretable values in hypertensive subjects.
（1）测量部位（下肢与上肢）对相应顺应性变量的影响；（2）舒张期脉搏轮廓（风箱模型衍生）分析在正常人和高血压患者中的总体可靠性。对20名血压正常者（116±12/68±8 mmHg）和27名原发性高血压患者（160±16/94±14 mmHg）在仰卧位时的桡动脉和胫后动脉进行动脉张力图记录。将每个受试者的总体平均数据拟合到一阶集总参数模型（基本风箱模型）以计算全身动脉顺应性（C(A)），并拟合到三阶集总参数模型（改良风箱模型）以计算近端顺应性（C(1)）和远端顺应性（C(2)）。尽管每个受试者的波形保真度很高，但一阶风箱模型在50%的血压正常者和41%的高血压患者中未得出可解释的（正值）C(A)值，而三阶模型在15%的血压正常者和41%的高血压患者中未能得出可解释的C(1)或C(2)结果。一阶时间常数、三阶模型曲线拟合常数中的3个中有2个、或C(A)、C(1)或C(2)均未发现测量部位之间的相关性（P>0.50）。腿部的所有3个顺应性变量的平均值均高于手臂（各P<0.05）。我们得出结论，手臂和腿部风箱模型衍生的顺应性值差异使全身模型假设无效，并提示区域循环特性有强烈影响。风箱模型衍生变量的有效性和实用性因测量部位之间缺乏相关性以及高血压患者中常见的不可解释值而进一步降低。
