Raju S, Fredericks R, Lishman P, Neglén P, Morano J
Department of Surgery, University of Mississippi Medical Center, Jackson 39216-4505.
J Vasc Surg. 1993 Mar;17(3):459-69.
We investigated the factors determining postexercise pressure and the relationship of venous valve closure and venous column segmentation to ambulatory venous pressure changes.
Valve closure and venous segmentation were observed during dynamic ascending phlebography in 40 nonrefluxive limbs and by duplex imaging in 25 normal limbs in healthy volunteers. Simultaneous volume (air plethysmography) and pressure studies during calf exercise were also carried out. Some studies used a simple mechanical model comprised of a collapsible latex tube ("calf pump") and a graduated "popliteal" valve.
The femoropopliteal venous column above the popliteal valve remains unsegmented and continuous during ambulatory venous pressure changes in response to calf muscle contraction. Therefore ambulatory venous pressure changes cannot be explained purely on the basis of hydrostatic column pressure changes. Postexercise pressure appears to be determined by a complex set of factors: (1) physical segmentation of the venous column below the popliteal valve (i.e., tibial valve closure); (2) tube collapse below the closed valve, which further aids in the breakup of the hydrostatic column pressure and dampens the effect of any reflux through or around the closed valve; (3) ejection fraction, which influences the degree of tube collapse; and (4) the interaction of the resultant pressure forces with the wall properties of the venous pump.
The mechanism of ambulatory venous pressure reduction is complex and multifactorial. The importance of venous wall characteristics as a determinant of postexercise pressure has not been previously appreciated. Changes in venous wall property after a thrombotic process, for example, could conceivably influence ambulatory venous pressure and recovery time in the absence of reflux.
我们研究了决定运动后压力的因素，以及静脉瓣膜关闭和静脉柱分段与动态静脉压力变化之间的关系。
在40条无反流肢体的动态上行静脉造影过程中观察瓣膜关闭和静脉分段情况，并通过双功成像观察25名健康志愿者正常肢体的情况。同时还进行了小腿运动期间的容积（空气容积描记法）和压力研究。一些研究使用了一个简单的机械模型，该模型由一个可折叠的乳胶管（“小腿泵”）和一个分级的“腘静脉”瓣膜组成。
在因小腿肌肉收缩引起的动态静脉压力变化过程中，腘静脉瓣膜上方的股腘静脉柱保持未分段且连续。因此，动态静脉压力变化不能单纯基于静水压力柱的变化来解释。运动后压力似乎由一系列复杂因素决定：（1）腘静脉瓣膜下方静脉柱的物理分段（即胫静脉瓣膜关闭）；（2）关闭瓣膜下方的管道塌陷，这进一步有助于破坏静水压力柱，并减弱通过关闭瓣膜或围绕关闭瓣膜的任何反流的影响；（3）射血分数，其影响管道塌陷程度；（4）合成压力与静脉泵壁特性之间的相互作用。
动态静脉压力降低的机制复杂且多因素。静脉壁特性作为运动后压力决定因素的重要性此前未被认识到。例如，血栓形成过程后静脉壁特性的变化可能会在无反流的情况下影响动态静脉压力和恢复时间。
