Editorial commentary
Lower leg perforators in human health and disease

In this issue’s review paper Čestmir Reček meticulously describes the activity of lower leg perforators in physiological settings and in patients with chronic venous disease [1]. Despite the importance of the role played by these veins for proper functioning of the venous system of the low extremities, their pathophysiology is still poorly understood. This leads to improper management of patients with chronic venous insufficiency.
Unfortunately, our understanding of this problem is unlikely to be substantially improved in the near future. At the moment, most of the research in phlebology is based on Doppler sonographic examinations. Nevertheless, even if the accuracy of this diagnostic tool is improving, this imaging technique is not very useful in resolving uncertainties related to the pathophysiology of venous outflow from the lower extremities. Direct pressure measurements in particular veins combined with anatomical assessment of these blood vessels and evaluation of the flow characteristics would be more reliable. However, considering the invasive nature of such studies, for ethical reasons they are not likely to be performed in the foreseeable future. Thus, we should rely on the results of research performed several decades ago [2-9]. However, becuase these studies usually examined a single physical parameter (for example: pressure), many questions remain unanswered.
It should be emphasised that – contrary to common thinking – blood flow is not driven by the difference in pressure between two points, but by the difference of total energy between these two points. This transmission of energy can be described using Bernoulli’s principle, which states that for an ideal fluid the function describing the total energy of such a fluid is constant along a streamline [10]. This total energy consists of the sum of the pressure energy (associated with the pressure), the kinetic energy (associated with flow velocity), and the potential energy (associated with gravitation).
Going back to the above-mentioned research on pressure changes in the leg veins, it is unclear how the other components of Bernoulli’s equation (especially the kinetic energy, i.e. flow velocity) were changing during these experiments. In addition, according to Bernoulli’s equation, the result of the pressure measurement in the blood vessel will be different depending upon how the pressure is measured. For example, if a catheter has an end-port sensor that is facing the...


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