In the past year, the SARS-CoV-2 epidemic situation has brought many changes to our everyday lives associated with the measures to limit the spread of infection, from movement restrictions to stricter hygienic standards and remote schooling and work. For many individuals, the latter forced them to sit for a larger part of the day than usual, and by closing the recreation spaces and fitness facilities, a general lack of recreation was observed, particularly in the urban environment. What does this mean in terms of our vein health?
This paper will focus in particular on a common vein disease also associated with a lack of exercise – deep vein thrombosis (hereinafter DVT). Vein thrombosis is a blood clot that forms in the deep or superficial vein resulting in partial or complete blood vessel blockage. In the mid-19th century, the famous German doctor Rudolf Virchow wrote that one of the major factors contributing to DVT is slowed blood flow in the vein.
DVT is most common in the veins of the lower limbs. The main function of the veins is to carry oxygen-depleted blood towards the heart to be reoxygenated in the lungs. In the lower limbs, venous blood travels upward from the feet, which means that gravity also acts on the travelling blood, and venous valves help us beat this force by preventing reflux, or backflow of venous blood, and enabling the one-way flow of the blood towards the heart. For venous circulation in the lower limbs, the activity of the shin muscles is also important.Veins are located between individual muscles, which serve as muscle pump helping to pump venous blood upward, thus preventing a delay or blood flow stasis (Figure 1). By actively contracting the shin muscles, the risk of GVT can be reduced.
A tendency for developing varicose veins, which is mostly genetically based, is observed among the population in developed countries (Europe, USA) with a predominantly sedentary lifestyle, and the incidence rises with age. Varicose veins result from chronic venous insufficiency, which in turn results from impaired activity of venous valves. A long-term sedentary lifestyle combined with age, pregnancy or obesity causes increased venous compliance and gravitation to lead to venous blood pooling in the lower legs; and in the presence of a congenital or acquired tendency to faster venous valve incompetence, chronic venous insufficiency might develop. Thus, dysfunctional valves fail to perform their primary function, i.e. preventing retrograde venous blood flow, which first leads to blood pooling in the veins around the ankles, resulting in increased venous pressure and, subsequently, to varicose veins (Figure 2). Blood pooling and the resulting increased blood vessel diameter prevent the valves from closing completely, and valve dysfunction (with a lack of action) is further worsened. In such condition, due to blood stasis, varicose veins are more prone to superficial venous thrombosis, which can spread to the deep venous system, thus leading to DVT.
Nevertheless, solely a lack of muscle activity and slowed venous blood flow are not the only risk factors for DVT. Rudolf Virchow also described other risk factors today jointly known as Virchow’s triad, including imbalance between the activated blood clotting factors and their inhibitors (e.g. use of contraception or tendency to blood clotting), vascular wall injury (surgical procedure, injury) and slowed and absent blood flow.
Which symptoms and signs should we watch for when DVT is suspected?
When inspecting the affected leg, first a swelling below the vascular obstruction due to a clot is observed. The leg feels tense and heavy, with a dull pain, which is more prominent while walking, the leg is warm to the touch, and subcutaneous veins might be more marked.
A severe form of DVT can be complicated by pulmonary embolism, i.e. a blockage of one or several pulmonary arteries with a clot, most commonly arising from the deep veins of the legs. The clot breaks loose from the vascular wall (Figure 3) and then travels through the venous system upward via the heart to the lungs. Pulmonary embolism may be fatal, so DVT must be diagnosed and treated as soon as possible.
Regular physical activity is not only good for the heart and arterial system but also for the veins. During extended periods of sitting, active contraction of the shin muscles is recommended, as the long-term risk of deep vein thrombosis or varicose veins can be reduced. If, despite this, a feeling of heavy and tired legs and swelling develops during prolonged sitting (at work or during long periods of travelling), the use of compression socks is recommended.
avtor: Romana Vranešič
1. Borch, Knut H, et al. “Physical Activity and Risk of Venous Thromboembolism. The Tromso Study.” Haematologica, Ferrata Storti Foundation, Dec. 2010, www.ncbi.nlm.nih.gov/pmc/articles/PMC2995567/
2. Office of the Surgeon General (US). “SECTION II: Reducing the Risk for DVT/ PE.” The Surgeon General’s Call to Action to Prevent Deep Vein Thrombosis and Pulmonary Embolism., U.S. National Library of Medicine, 1 Jan. 1970, www.ncbi.nlm.nih.gov/books/NBK44186/.
3. Košnik, Mitja, et al. Interna Medicina. Medicinska Fakulteta, 2018.
4. Cardiovascular Physiology Concepts. Factors Promoting Venous Return. (dostopno na: https://www.cvphysiology.com/Cardiac%20Function/CF018)
5. Sachdeva A, Dalton M, Lees T. Graduated compression stockings for prevention of deep vein thrombosis. Cochrane Database of Systematic Reviews 2018, Issue 11. Art. No.: CD001484. DOI: 10.1002/14651858.CD001484.pub4
Sources of figures:
Figure 1: Overview of muscle pump, adapted from: http://comprecarelymphatics.com/welcome-to-our-practice/about-lymphedema/lymphedema-and-chronic-venous-insufficiency/
Figure 2: Overview of varicose veins, adapted from: https://www.physio-pedia.com/Varicose_Veins
Figure 3: Overview of deep vein thrombosis, adapted from: https://www.bestveintreatment.com/services/deep-vein-thrombosis-dvt