Tauraginskii Roman A, Lurie Fedor, Simakov Sergei, Agalarov Rishal
Clinical and Scientific Department, International Institution of Health Care and Additional Education Research Institute of Clinical Medicine, Irkutsk, Russia; LLC Vein Center "Antireflux," Surgut, Russia.
Jobst Vascular Institute, Toledo, Ohio; Division of Vascular Surgery, University of Michigan, Ann Arbor, Mich.
J Vasc Surg Venous Lymphat Disord. 2021 Sep;9(5):1282-1290. doi: 10.1016/j.jvsv.2020.12.070. Epub 2020 Dec 16.
The gravitational pressure gradient is considered the driving force of venous reflux. The results from our previous study demonstrated that gravitational force is not a necessary condition for the occurrence of venous reflux. We hypothesized that a force exists in addition to gravity that drives venous reflux. The present study was designed to test this hypothesis by measuring the acceleration of blood flow during venous reflux in a clinical study and by simulating reflux ex vivo in physical models.
A total of 80 lower extremities of 80 patients with primary incompetence of the great saphenous vein were included in the present study. The cross-sectional area of the great saphenous vein, peak velocity of venous reflux (PV), and time required to achieve the PV (t, seconds) were measured on duplex ultrasound scans taken with the patient in the standing rest position. Noncycling operator-dependent distal cuff inflation-deflation was used as the reflux provoking maneuver. The acceleration of venous reflux (a) was calculated as a = PV/t in m/s. Physical models were used to demonstrate the difference in acceleration between the free-fall stream and the flow forced by suction.
The magnitude of a was greater than gravity in 24 of 80 extremities (30%), with a range of 9.83 to 24.13 m/s. The maximum observed value of a was approximately 2.5g (24.13 m/s). The a weakly, but statistically significant inversely, correlated with the subject height (r = -0.26; P = .001). The difference in water flow acceleration was 2.5 times between the free-fall model and suction model (9.07 ± 0.2 m/s vs 23.32 ± 2.6 m/s, respectively).
The acceleration of blood flow during reflux exceeded the value of gravitational acceleration, suggesting the action of an additional nongravitational force. The calf muscle pump might create such force by negative pressure during muscle diastole.
重力压力梯度被认为是静脉反流的驱动力。我们之前的研究结果表明，重力并非静脉反流发生的必要条件。我们推测，除重力外还存在一种驱动静脉反流的力。本研究旨在通过在临床研究中测量静脉反流期间的血流加速度以及在物理模型中进行体外反流模拟来验证这一假设。
本研究纳入了80例大隐静脉原发性功能不全患者的80条下肢。在患者静立休息位进行的双功超声扫描中，测量大隐静脉的横截面积、静脉反流峰值速度（PV）以及达到PV所需的时间（t，秒）。使用非周期性、依赖操作者的远端袖带充气 - 放气作为引发反流的动作。静脉反流加速度（a）的计算方式为a = PV/t（单位：m/s）。使用物理模型来展示自由落体血流与抽吸驱动血流之间的加速度差异。
80条下肢中有24条（30%）的a值大于重力加速度，范围为9.83至24.13 m/s。观察到的a的最大值约为2.5g（24.13 m/s）。a与受试者身高呈弱但具有统计学意义（P = 0.001）的负相关（r = -0.26）。自由落体模型和抽吸模型之间的水流加速度差异为2.5倍（分别为9.07 ± 0.2 m/s和23.32 ± 2.6 m/s）。
反流期间的血流加速度超过了重力加速度的值，提示存在一种额外的非重力作用力。小腿肌肉泵可能在肌肉舒张期通过负压产生这种力。
