Ultrasound signs of varicose veins

Ultrasound diagnosis of chronic venous insufficiency and varicose veins

The most common form of chronic venous insufficiency is varicose veins. The cause of the disease is the failure of the valvular apparatus of the superficial and deep veins of the lower extremities with the appearance of pathological venous reflux. A mandatory symptom of varicose veins is the specific changes in the subcutaneous veins of the lower extremities: enlargement, swelling through the skin and tortuosity, visible in the vertical position and disappearing in the horizontal. Other clinical symptoms may include edema, increased volume, cyanosis of the skin of distal legs, trophic skin disorders predominantly of the lower third of the medial surface of the shin.

Meanwhile, it should be emphasized that all listed signs are inherent in other chronic pathology of the venous system of the lower limbs - post-thrombotic disease. Differences concern the localization of varicose veins and the timing of the appearance of clinical signs. Virtually all patients with varicose veins first develop subcutaneous vein changes and only after three or more years have other symptoms of the disease. Experience shows that in the case of a developed clinical picture, the diagnosis of varicose veins is straightforward. A more difficult task is to diagnose the initial forms of the disease and its atypical manifestations. In this situation, special methods of investigation are needed, they are also shown in cases when it is difficult for the surgeon to answer questions concerning pathogenetic factors, among which the most important are: valvular insufficiency of deep veins; retrograde blood flow through the trunks of the large and small saphenous veins; veno-venous discharge through perforating veins of the lower leg.

Examination is carried out in the position of the patient lying down, as well as standing, without reinforced support on one or the other lower limb. All patients are evaluated for blood flow in the large and small saphenous veins, perforating veins, and deep veins of the lower limbs. To do this, apply the B-mode, color and energy mapping modes, spectral Doppler, using sensors with a frequency of 5-13 MHz.

With varicose veins, the vein wall is not thickened and is the same throughout. The vein can be easily squeezed by the sensor, the internal diameter changes when the patient undergoes straining. As a rule, visualized varicose dilated saphenous veins.

Inside the vein, there are no formations other than the valves. The latter are represented, as a rule, by two semicircular shadows, changing the position in the lumen of the vein, depending on the respiratory movements. At the height of the Valsalva test, valve flaps do not close at the ectasia of the vein and even prolapse.

Clarification of the localization of the valve speeds up its search during surgical interventions. In addition, the surgeon must provide information not only on the presence of reflux, but also on its nature and extent.

Further description of the superficial veins of the lower extremities is given in the example of a large saphenous vein, since the changes in blood flow revealed in it completely coincide with the blood flow data obtained in the study of a small saphenous vein. 

Normally, the bloodstream in the trunk of a large saphenous vein, using color and energy mapping, easily locks throughout the vein from the osteal valve to the medial malleolus.

With the use of these modes of visualization of blood flow in the vein, there is no problem in identifying any reflux through the osteal valve, refluxes throughout the entire trunk of the large saphenous vein, refluxes from the tributaries and perforating veins.

The use of B-flow significantly changed the echographic picture of the previously known variants of blood flow in the system of large and small saphenous veins. It turned out that the normal subcutaneous vein synchronously works with its inflows only in 68% of cases. In these patients, the blood flow simultaneously moves both in the trunk of the large saphenous vein, and enters it from its tributaries.

In 32% of the observations, the blood flow moves along the trunk of the large saphenous vein, but does not enter from the tributaries. In this situation, there is no blood flow in the inflows of the large saphenous vein. Clearing them is just empty. Blood flow is determined only in the trunk of the large saphenous vein. After the entire volume of blood flow from the trunk of the large saphenous vein enters the common femoral vein, the trunk of the large saphenous vein becomes completely empty. Only the walls of the vessel and its anechogenous lumen are visible. After the trunk of the large saphenous vein is freed from the blood flow, the empty vein of the vein is synchronized, blood from all visible tributaries arrives, which gradually fills the lumen of the large saphenous vein from the medial malleolus to the osteal valve. At the same time, a large subcutaneous vein begins to fill and from the veins of the foot. And, first of all, a part of the large saphenous vein located on the lower leg, and then more proximal parts of the trunk of the large saphenous vein, is filled.

If in the femoral part of the large saphenous vein is available its inflow or tributaries, the blood can fill only a certain section of the trunk of the large saphenous vein directly in the place where there is a flow of inflow or tributaries into the main trunk of the vein. Proximal and distal to the inflow of inflow or tributaries, the trunk of the large saphenous vein is not filled with flow. This inflow or tributaries located in the region of the thigh operates synchronously with the inflows of the large saphenous vein in the region of the shin, but not with the trunk of the vein. Gradually, the blood flow from the trunk of the large saphenous vein in the region of the shin reaches the part of the trunk of the large saphenous vein, which is filled with blood from the influx in the region of the thigh, then spreads further to the ostial valve, and its entire volume enters the common femoral vein at once. At the time when the entire volume of blood begins to flow into the common femoral vein, the inflows are completely emptied, and already their lumen becomes anechoic. Then everything happens again.

Inflows are simultaneously filled with blood (the first phase), from them it enters the trunk of the large saphenous vein (the second phase), the trunk is completely filled (the third phase), and the entire volume of blood from the trunk of the large saphenous vein simultaneously enters the common femoral vein (the fourth phase) .

The role of the inflows of the large saphenous vein in the development of varicose veins is very significant. The nature of the blood flow in the trunk of the large saphenous vein depends on the angle of inflow of the inflow into the trunk of the large saphenous vein. The smaller the angle (with respect to the antegrade direction of the blood flow in the trunk of the large saphenous vein) formed when the inflow of the influx into the trunk of the large saphenous vein, the direction of the two bloodstreams more closely coincides with each other and there is no turbulent flow at the confluence of the inflow and trunk of the vein. This was noted in those cases when the angle of inflow of inflow into the trunk of the vein does not exceed 70 °. If the angle between the inflowing tributary and the trunk of the large saphenous vein is sufficiently large and exceeds 70 °, a turbulent blood flow appears in the trunk of the large saphenous vein, which can not break up in the proximal direction. Blood flow in the trunk of the large saphenous vein splits, and before the bifurcated part of it turbulent blood flow is clearly defined.

The development of varicose veins can be predicted in the preclinical stage of the disease. The main factor here is not the primary valve failure, but the direction of blood flow in the inflows of the large and small saphenous veins systems when merging with the main blood flow in the trunks of the large and small saphenous veins.

The role of perforating veins in the occurrence of horizontal reflux is fully proved. Ultrasonic studies allow visualization of perforating veins with a diameter of 1.5-2.3 mm. At such sizes, the perforating vein is easy to detect by completing the B-mode by the investigation in the DCS or EHD mode.

It is advisable in patients with varicose veins to perform ultrasound examination of the perforating veins of the lower extremities together with the vascular surgeon. Usually it is done on the eve of the day of surgery. The presence of a vascular surgeon in the ultrasound diagnosis room has an important goal - the joint search and masking of the inconsistency of perforating veins. In addition to identifying perforating veins, the vascular surgeon is provided with complete information on the state of the entire system of superficial and deep veins of the lower extremities with localization of venous-venous discharges and permeability of veins in all parts of the lower extremities, the iliac and inferior vena cava.

The incompetence of perforators with a diameter of 1.5-2 mm or more is not difficult to detect using color mapping supplemented with spectral Doppler. As for perforators with a diameter of 1 mm or less, there are certain difficulties for these ultrasonic methods in terms of detecting the incompetence of perforating veins. In a perforating vein 0.5 mm in diameter, it is not easy to identify the direction of the blood flow and, most importantly, to establish the inconsistency of a venous vessel of a given diameter. In a perforating vein with a diameter of 0.2-0.4 mm, this is even more difficult. Using the B-flow mode, in the perforating vein, you can clearly see how or how the blood flow moves along the vessel.

It should be remembered that the angle of fusion of the directions of blood flow from the perforating vein and the blood flow in the deep vein of the lower limb plays an important role in the occurrence of the incompetence of perforating veins. Most often, unsound perforators are found in cases where the angle between the merger of the antegrade directions of the blood streams from the perforating vein and in the deep vein was greater than 70 °. Probably, the angle of the connection of blood from the perforating and deep veins is more than 70 ° is one of the determining factors in the subsequent development of the inconsistency of the perforating vein.

The coincidence of the directions of the blood flow does not lead to the formation of turbulent parts of the blood flow in the deep vein at the place where the perforating vein enters it. Thus, in these cases, such a perforator, in the absence of other predisposing factors, does not lose its validity.

Surface veins can fill the bloodstream in a non-synchronous manner with deep veins. The first to fill the trunk of superficial veins. There comes a short moment when the pressure in the superficial veins exceeds the pressure in the deep veins of the lower limbs. By increasing the pressure in the superficial veins, perforating veins are filled. At this time, deep veins have empty trunks, without signs of their blood filling (diastole phase of the "muscular-venous pump"). Blood flow from the perforating veins enters the empty deep veins. Simultaneously with the beginning of emptying of perforating veins, deep venous trunks begin to be filled from other sources. Then the following happens: deep veins are completely filled with blood flow and after that instantaneous whole volume of blood flow from the deep veins of the lower extremities comes in the proximal direction.

Post-thrombophlebitis develops as a result of acute thrombosis of deep veins. The outcome of the thrombotic process depends on the severity of the retraction of the blood clot and the spontaneous lysis of the thrombus. In some cases complete recanalization occurs, in others full obliteration, in the third - the permeability of the vessel is partially restored. Most often, after thrombosis of the main veins, a partial recanalization of the lumen of the vessel with phlebosclerosis and valvular insufficiency occurs. As a result, severe violations of hemodynamics develop in the limb: venous hypertension, pathological discharge of blood into the subcutaneous veins and varicose veins, marked changes in the microcirculation system. Based on these prerequisites, ultrasound examination of the patient should give an answer to the following questions:

1. Whether deep veins are passable?
2. on what extent is the valvular apparatus of the deep veins damaged?
3. in what state are the valves of superficial veins?
4. where localized insufficient communication veins?

Post-thrombotic lesion of the main veins has a number of principal ultrasound features. Organic avalvulation of the affected venous segment does not allow visualizing the functioning valves of the valvular apparatus in it. The latter are completely destroyed or adhered to the walls of the vein. Aseptic inflammation leads to a perivasal reaction, due to which the wall of the vessel thickens several times compared with the intact. Ultrasound examination reveals the heterogeneity of the vein lumen due to the presence of thrombotic masses of varying degrees of organization. The affected venous segment becomes rigid and ceases to respond to compression.

The study in the regimes of CDC and EHD reveals several types of recanalization of the venous segment. The most common cable type, characterized by the fact that in the lumen of the vein, several channels of independent blood flow are detected. Less often, recanalization proceeds through a single-channel type. In this case, usually along the front and back wall there is a channel with a blood flow, occupying from one third to one half of the lumen of the vessel. The rest of the lumen is filled with organized thrombotic masses. It is significant that a large number of compensatory collaterals are visualized in the occluded vein zone.

In conclusion, it should be emphasized that the use of modern ultrasound technology in the diagnosis of venous disorders of the lower extremities greatly expands the current views of physicians on pathophysiology and hemodynamics through the veins of the legs, facilitates the transition to an adequate choice of surgical treatment and physiologically justified methods of correction of venous insufficiency of the lower limbs.

It should be noted that ultrasonic evaluation of the venous and arterial system of the lower limbs may seem incomplete if questions of functional study of Doppler ultrasound of arterial insufficiency of the lower extremities and directly related prosthetic and rehabilitation aid remain unaddressed, which will be covered in the last chapter.