Ultrasound signs of acute venous thrombosis

Ultrasound diagnosis of acute venous thrombosis

Acute venous thromboses of the inferior vena cava system are divided into embologene-dangerous (flotating or non-occlusive) and occlusive. Non-occlusive thrombosis is the source of pulmonary embolism. The system of the superior vena cava gives only 0.4% of the pulmonary artery thromboembolism, the right heart is 10.4%, while the lower vena cava is the main source of this formidable complication (84.5%).

Intravital diagnosis of acute venous thrombosis can be established only in 19.2% of patients who died from pulmonary embolism. The data of other authors indicate that the frequency of correct diagnosis of venous thrombosis before the development of a lethal embolism of the pulmonary artery is low and ranges from 12.2 to 25%.

Postoperative venous thrombosis is a very serious problem. According to BC Savelyev, postoperative venous thrombosis develops after general surgical interventions on average in 29% of patients, in 19% of cases after gynecological interventions and in 38% of transvesical adenomectomies. In traumatology and orthopedics, this percentage is even higher and reaches 53-59%. A special role is assigned to early postoperative diagnosis of acute venous thrombosis. Therefore, all patients presenting a certain risk in terms of postoperative venous thrombosis should undergo a complete examination of the inferior vena cava system at least twice: before and after surgery.

It is considered important to identify violations of the patency of the main veins in patients with arterial insufficiency of the lower extremities. This is especially necessary for a patient who is supposed to have an operative procedure to restore blood flow to the limb, the effectiveness of such surgical intervention is reduced in the presence of various forms of obstruction of the main veins. Therefore, all patients with limb ischemia should examine both arterial and venous vessels.

Despite the significant advances made in recent years in the diagnosis and treatment of acute venous thrombosis of the inferior vena cava and peripheral veins of the lower extremities, interest in this problem has not only diminished but has grown steadily in recent years. A special role is still assigned to the issues of early diagnosis of acute venous thrombosis.

Acute venous thrombosis, by its localization, is divided into thromboses or the caudal segment, the femoropopliteal segment and thrombosis of the crural veins. In addition, thrombotic lesions can be affected by large and small saphenous veins. 

The proximal border of acute venous thrombosis can be located in the infrarenal part of the inferior vena cava, suprarenal, reach the right atrium and be in its cavity (echocardiography is indicated). Therefore, an examination of the inferior vena cava is recommended starting from the right atrial area and then gradually descending down to the infrarenal part of the vein and the place of confluence in the inferior vena cava of the iliac veins. It should be noted that the most careful attention should be paid not only to examining the trunk of the inferior vena cava, but also the veins that flow into it. First of all, they include renal veins. Usually, thrombotic damage of the renal veins is caused by volumetric kidney formation. Do not forget that the cause of thrombosis of the inferior vena cava may be the ovarian veins or the testicle veins. Theoretically, it is believed that these veins, because of their small diameter, can not lead to pulmonary embolism, especially since the prevalence of thrombus to the left renal vein and inferior vena cava due to the left ovarian or testicular vein, due to the tortuosity of the latter, looks casually. However, it is necessary to always seek to examine these veins, at least their mouths. In the presence of thrombotic occlusion, these veins increase slightly in size, the lumen becomes non-uniform and they are well established in their anatomical regions.

With ultrasonic triplex scanning, venous thromboses are divided relative to the lumen of the vessel into parietal, occlusive and floating thrombi.

Ultrasound signs of parietal thrombosis consider the visualization of a thrombus with the presence of free blood flow in this area of the altered lumen of the vein, the absence of complete collapse of the walls during compression of the vein by the sensor, the presence of a defect in filling with CDC, the presence of spontaneous blood flow in spectral Doppler.

Occlusive thrombosis is considered, the signs of which are absence of wall collapse during compression of the vein by the sensor, as well as visualization of inclusions of various echogenicity in the vein of the vein, absence of blood flow and staining of the vein in the modes of spectral Dopplerography and CDC. The ultrasound criteria of floating thrombus are: visualization of thrombus as an echogenic structure located in the lumen of the vein with free space, oscillatory movements of the thrombus top, absence of contact of the vein walls during compression by the sensor, presence of free space in performing respiratory tests, enveloping the type of blood flow with color coding of the flow , the presence of spontaneous blood flow in the spectral Doppler.

The constant interest is caused by the possibilities of ultrasonic technologies in diagnosing the age of thrombotic masses. Identification of the signs of floating thrombus in all stages of thrombosis organization allows to increase the efficiency of diagnosis. Especially valuable is the earliest diagnosis of fresh thrombosis, which allows taking early preventive measures for thromboembolism of the pulmonary artery.

After comparing the ultrasonic data of floating thrombi with the results of morphological studies, we came to the following conclusions.

Ultrasonic signs of a red blood clot are a hypoechoic fuzzy contour, anehogenicity of the thrombus in the apex region and hypoechoogenicity of the distal part with separate echogenic inclusions. Signs of a mixed thrombus are the heterogeneous structure of a thrombus with a hyperechogenic, distinct contour. In the structure of a thrombus in the distal sections heteroecogenic inclusions prevail, in the proximal parts - mainly hypoechogenic inclusions. Signs of a white blood clot - a floating thrombus with clear contours, a mixed structure with predominance of hyperechoic inclusions, and in the CDC, fragmental streams through thrombotic masses are recorded.