Spontaneous blood flow. Main blood flow what is it
From this article, you will learn how ultrasound of the vessels of the lower extremities is performed, to whom the procedure is prescribed. What can be diagnosed with ultrasound.
Article publication date: 06/11/2017
Article last updated: 05/29/2019
Doppler ultrasonography is ultrasound. This diagnostic method, unlike other methods of examining blood vessels, is able to show the speed of blood flow, which allows you to accurately diagnose the severity of the disease that disrupts blood circulation.
For any vessels, this procedure is carried out according to the same principle - using an ultrasound sensor, like any ultrasound. More often this procedure is required to examine the veins, it is used less often to examine the arteries.
Different doctors can refer you to this examination: therapist, phlebologist, angiologist. The procedure is carried out by an ultrasound specialist.
Indications
Ultrasound of the vessels of the legs is prescribed for the diagnosis of such diseases:
- Phlebeurysm.
- Thrombophlebitis.
- Atherosclerosis.
- Thrombosis.
- Spasm of the arteries of the legs (angiospasm).
- Arterial aneurysms (their expansion).
- Obliterating endarteritis (an inflammatory disease of the arteries that leads to their narrowing).
- Arteriovenous malformations (abnormal connections between arteries and veins).
What are the symptoms of ultrasound
Patients are referred to this diagnostic procedure for suspected vascular diseases of the legs. Your doctor may order an ultrasound scan if you experience these symptoms:
- swelling of the legs;
- heaviness in the legs;
- frequent blanching, redness, blue of the legs;
- goosebumps, numbness in the legs;
- pain when walking less than 1000 meters;
- cramps in the calf muscles;
- vascular "asterisks", "grids", protruding veins;
- tendency to freeze feet, cold feet even when warm;
- the appearance of bruises on the legs even after the slightest blow, or for no reason at all.
When Doppler Ultrasound Is Needed?
Undergo dopplerography of the vessels of the legs as a preventive measure once every six months or a year if you are at risk. To diseases of the vessels of the lower extremities are prone to:
- overweight people;
- engaged in physical labor (loaders, athletes);
- those who constantly stand or walk a lot at work (teachers, security guards, couriers, waiters, bartenders);
- those who have already been diagnosed with atherosclerosis of other vessels;
- people whose direct relatives suffered from vascular diseases;
- those with diabetes;
- smokers;
- people over 45;
- women during pregnancy and menopause;
- women taking oral contraceptives for a long time.
Training
The procedure does not require any complex preparation.
The only thing is that the feet must be clean. If, due to individual characteristics, you have thick hair on your legs, it is advisable to shave it off so that it is easier for the doctor to work.
On the day of the procedure, do not drink alcohol, stimulating drinks (coffee, strong tea, energy drinks), do not exercise your legs (do not run, do not lift weights, do not go to training). Do not smoke 2 hours before ultrasound of the vessels of the lower extremities (and other vessels too). It is better to go for examination in the morning.
Take some paper towels or towels with you to dry your feet afterwards. Also bring a referral for an ultrasound scan from your doctor and the results of previous vascular examinations.
How the study is done
First, you free your legs from clothing.
The examination will be performed standing or lying down. The doctor applies an ultrasound gel and moves the ultrasound probe over the legs.
The image of your vessels is displayed on the specialist's monitor. Immediately in the course of the procedure, it analyzes and records the received data.
If you are being examined lying down, the doctor will first tell you to lie on your stomach and raise your legs up on your toes. Or you can put a roller under the feet. In this position, it is most convenient for a specialist to examine the popliteal, peroneal, small saphenous and sural veins, as well as the arteries of the back surface of the legs. Then you will be asked to roll over on your back and slightly bend your knees. In this position, the doctor can examine the veins and arteries of the front surface of the legs.
Anatomy of the leg veins. Click on photo to enlarge During an ultrasound scan to detect reflux (reverse blood discharge), the doctor can perform special tests:
- Compression test. The limb is compressed and the blood flow in the compressed vessels is assessed.
- Valsalva test. You will be asked to inhale, pinch your nose and mouth, and strain a little while trying to exhale. If there is an initial stage of varicose veins, reflux may occur during this test.
Dopplerography of vessels in total takes about 10-15 minutes.
At the end of the examination, you wipe your legs from the remnants of the ultrasound gel, get dressed, pick up the result and you can go.
What does ultrasound of the vessels of the legs show
Using Dopplerography of the lower extremities, you can examine the following vessels of the legs:
During this diagnostic procedure, the doctor can see:
- the shape and location of the vessels;
- vessel lumen diameter;
- condition of the vascular walls;
- condition of arterial and venous valves;
- the speed of blood flow in the legs;
- the presence of reflux (reverse discharge of blood, which is often found in varicose veins);
- the presence of blood clots;
- the size, density and structure of the thrombus, if any;
- the presence of atherosclerotic plaques;
- the presence of arteriovenous malformations (connections between arteries and veins, which should not normally be present).
Norms of UZDG, conclusion with explanations
The veins should be passable, not dilated, the walls should not be thickened. The lumen of the arteries is not narrowed.
All valves should be consistent, there should be no reflux.
The blood flow velocity in the femoral artery averages 100 cm/s, in the arteries of the leg - 50 cm/s.
Atherosclerotic plaques and blood clots in the vessels should not be detected.
Pathological connections between vessels are normally absent.
An example of a normal conclusion of an ultrasound scan of the veins of the legs and explanations for it
Conclusion: all veins on both sides are passable, compressive, the walls are not thickened, the blood flow is phasic. No intraluminal structures were identified. Valves are wealthy at all levels. There are no pathological refluxes during compression tests and Valsalva tests.
| Theses from the conclusion | What do they mean |
|---|---|
| All veins on both sides are passable, compressive, the walls are not thickened. | All veins on both sides are passable, which means that blood can flow freely through the vessels. Compressive - that is, they have not lost their natural tone, they can shrink. The walls are not thickened - this indicates that there are no inflammatory and other pathological processes. |
| The blood flow is phasic. | The blood flow is phasic - faster on exhalation and slower on inspiration. This is how he should be. |
| No intraluminal structures were identified. | Intraluminal structures were not revealed - there are no atherosclerotic plaques, blood clots and other inclusions that should not be there. |
| Valves are wealthy at all levels. | The valves are well-founded - that is, they normally perform their functions and do not allow the reverse flow of blood. |
| There are no pathological refluxes during compression tests and Valsalva tests. | There are no pathological refluxes during the performance of the tests - the blood under no circumstances is discharged in the opposite direction, which indicates a healthy blood circulation. |
Contraindications
Dopplerography of the vessels of the lower extremities is an absolutely safe procedure. It has no contraindications and age restrictions.
It can be performed at any frequency and for any people, including:
- children of any age;
- the elderly;
- people with chronic diseases;
- patients with acute inflammatory diseases;
- those who have a pacemaker implanted (they can direct an ultrasound probe to their legs, but ultrasound of the chest organs cannot be done);
- pregnant and lactating women;
- those who are allergic to contrast agents (angiography, for example, cannot be performed in this case);
- people weighing more than 120 kg (but it is impossible to conduct an MRI scan for obese patients on most devices, since they are not designed for such dimensions).
The only restriction that can be tolerated is an allergy to the ultrasound gel. It occurs in isolated cases. And it is not an absolute contraindication to performing diagnostics. An allergic reaction can be avoided by choosing a hypoallergenic gel that is right for you.
Gel for ultrasound Summary, advantages of the procedure
Dopplerography of the vessels of the lower extremities is an absolutely painless diagnostic method. It does not cause any side effects and has no contraindications (with the exception of an allergy to the ultrasound gel). According to scientific studies, ultrasonic waves do not cause any harm to the body, so ultrasound of the vessels of the legs can be performed at any frequency.
Unlike MRI, ultrasound has no restrictions on the patient's weight and can be performed on people with a pacemaker installed.
This procedure can be performed in patients with allergies to contrast agents and other iodine-containing drugs, which cannot be said about angiography and contrast phlebography.
Among the advantages can be noted and low cost. Dopplerography is significantly cheaper than MRI, angiography and phlebography.
The undeniable advantages of the method include the speed of execution. Ultrasound is done in a maximum of 15 minutes. An MRI, for example, takes at least half an hour.
It can be said that Dopplerography is the most optimal method for examining blood vessels that exists today. It combines high accuracy, affordable cost, high speed and almost complete absence of contraindications.
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Tasks of instrumental diagnostics of CVI.
- Assessment of the state of deep veins, their patency and functions of the valve apparatus.
- Detection of blood reflux through the ostial valves of the great and small saphenous veins.
- Determination of the extent of damage to the valvular apparatus of the trunks of the saphenous veins, as well as clarification of the features of their anatomical structure.
- Identification and precise localization of insufficient perforating veins.
The basis of modern CVI diagnostics is ultrasonic methods - Dopplerography and angioscanning.
Doppler ultrasound is based on the Doppler effect - a change in the frequency of a sound signal when it is reflected from a moving object (in this case, from blood cells). The difference between the generated and reflected waves is recorded as an audio or graphical signal.
The examination is carried out in the horizontal and vertical positions of the patient. The standard "windows" for the study are the retromalleolar region (the posterior tibial veins are located), the popliteal fossa (the popliteal and small saphenous veins are located) and the upper third of the thigh (the area of the femoral and great saphenous veins). Studied spontaneous and stimulated blood flow through the deep and saphenous veins.
Spontaneous (antegrade) blood flow is determined in large caliber veins. Its distinctive feature is its connection with the respiratory movements of the chest, so its sound resembles the sound of the wind, which intensifies during the exhalation phase and weakens during inhalation. Stimulated venous blood flow is necessary to assess the functions of the valvular apparatus of the main veins. In the study of proximal vessels (femoral and great saphenous veins), a Valsalva test is used. In healthy people, during inhalation, the venous murmur weakens, at the moment of straining it completely disappears, and with subsequent exhalation it sharply increases. The insufficiency of the valves of the examined vein is indicated by the noise of a retrograde blood wave that occurs when the patient strains.
The state of the tibial, popliteal and small saphenous veins is assessed using proximal and distal compression tests. In the first case, manual compression of the limb segment above the ultrasound transducer is performed. At the same time, intravenous pressure rises and, in case of valve insufficiency, a signal of retrograde blood flow is recorded. With a distal compression test, the limb segment is compressed below the sensor. This leads first to the appearance of an antegrade, and after decompression of a retrograde blood wave.
Ultrasonic angioscanning allows you to get an image of the studied veins in real time. The value of the study increases with the simultaneous use of Doppler or color Doppler imaging modes. Standard "windows" and samples for conducting a study of the venous system are similar to those described above. Retrograde blood flow is determined by reversing the audio or graphic Doppler signal or by changing the color of the blood flow in color mapping.
To date, ultrasound angioscanning is the most informative diagnostic method that allows visualizing almost the entire venous bed from the veins of the foot to the inferior vena cava. The results of the study make it possible to establish the cause of chronic venous insufficiency with a high degree of accuracy by detecting the consequences of venous thrombosis in deep veins (occlusion of a vein or recanalization of its lumen) or, on the contrary, their unchanged wall with wealthy valves. In case of varicose veins, the extent of blood reflux along the trunks of the main superficial veins is determined. In addition, ultrasonic angioscanning makes it possible to reliably localize insufficient perforating veins (Fig. 1), which facilitates their search during surgery.
Rice. 1. Ultrasound angioscanogram of a patient with varicose veins. An incompetent perforating vein connecting the deep vein with the superficial one is located.
Radionuclide phlebography. A distinctive feature of this minimally invasive study is the possibility of obtaining information about the features of the functioning of the venous bed of the lower extremities. The study is carried out in the vertical position of the patient. After applying a tourniquet over the ankles, blocking the lumen of the saphenous veins, a radionuclide is injected into the vein of the rear of the foot. Then the patient begins to rhythmically bend and unbend the foot, without lifting the heels from the support. Such an imitation of walking "turns on" the musculo-venous pump of the lower leg, and the radiopharmaceutical begins to move through the deep veins. The detector of the gamma camera registers its movement (Fig. 2), fixing the perforating discharge into superficial veins, isotope retention zones (segments with valvular insufficiency) or its absence (occlusion areas). Of great diagnostic importance is the rate of evacuation of the drug from different parts of the venous bed, which makes it possible to judge the extent of the violation of the venous outflow in a particular zone.
Rice. 2. Radioisotope phleboscintigram. Photograph of a patient with left-sided iliac vein occlusion. The outflow of blood from the affected limb through collaterals in the suprapubic region is carried out through the right iliac veins.
X-ray contrast phlebography. For its implementation, it is necessary to introduce a water-soluble radiopaque preparation into the main veins. This method is considered one of the most informative, but at the same time quite traumatic and unsafe for the patient (allergic reactions to a contrast agent, venous thrombosis, hematomas). X-ray phlebography provides the most complete picture of the anatomical and morphological features of the venous bed, so it is still indispensable when planning reconstructive operations on deep veins (valvular plastics, vein transposition, etc.) in patients with post-thrombophlebitic disease. With varicose veins, this research method is not currently used, since the information obtained from ultrasound and radionuclide research is sufficient to determine the tactics of treating the patient.
Saveliev V.S.
Surgical diseases
This information is intended for healthcare and pharmaceutical professionals. Patients should not use this information as medical advice or recommendations.
Doppler sonography of peripheral vessels. Part 2.
N.F. Beresten, A.O. Tsypunov
Department of Clinical Physiology and Functional Diagnostics, RMAPE, Moscow, Russia
AT Part I This article outlined the main methodological approaches to the study of peripheral vessels, outlined the main quantitative Doppler sonographic parameters of blood flow, listed and demonstrated the types of flows. AT Part II Based on their own data and literature sources, the main quantitative indicators of blood flow in various vessels in normal and pathological conditions are given.
The results of the study of blood vessels are normal
Normally, the contour of the walls of the vessels is clear, even, the lumen is echo-negative. The course of the main arteries is rectilinear. The thickness of the intima-media complex does not exceed 1 mm (according to some authors - 1.1 mm). Dopplerography of any arteries normally reveals laminar blood flow (Fig. 1).
A sign of laminar blood flow is the presence of a "spectral window". It should be noted that if the angle between the beam and the blood flow is not correctly corrected, the "spectral window" may also be absent in laminar blood flow. With Dopplerography of the arteries of the neck, a spectrum characteristic of these vessels is obtained. When examining the arteries of the extremities, the main type of blood flow is revealed. Normally, the walls of the veins are thin, the wall adjacent to the artery may not be visualized. In the lumen of the veins, foreign inclusions are not detected, in the veins of the lower extremities, valves are visualized in the form of thin structures that oscillate in time with breathing. The blood flow in the veins is phasic, its synchronization with the phases of the respiratory cycle is noted (Fig. 2, 3). When conducting a respiratory test on the femoral vein and when performing compression tests on the popliteal vein, a retrograde wave lasting more than 1.5 seconds should not be recorded. The following are indicators of blood flow in various vessels in healthy individuals (Tables 1-6). Standard approaches for Doppler sonography of peripheral vessels are shown in fig.4.
The results of the study of blood vessels in pathology
Acute arterial obstruction
embolism. On the scan, the embolus looks like a dense rounded structure. The lumen of the artery above and below the embolus is homogeneous, echo-negative, does not contain additional inclusions. When assessing the pulsation, an increase in its amplitude proximal to the embolism and its absence distal to the embolism are revealed. Dopplerography below the embolus determines the altered main blood flow or the blood flow is not detected.
Thrombosis. An inhomogeneous echostructure oriented along the vessel is visualized in the lumen of the artery. The walls of the affected artery are usually compacted, have increased echogenicity. Dopplerography reveals a main altered or collateral blood flow below the site of occlusion.
Chronic arterial stenoses and occlusions
Atherosclerotic lesion of the artery. The walls of the vessel affected by the atherosclerotic process are compacted, have increased echogenicity, and an uneven internal contour. With significant stenosis (60%) below the site of the lesion, a main altered type of blood flow is recorded on the Dopplerogram. With stenosis, turbulent flow appears. The following degrees of stenosis are distinguished depending on the shape of the spectrum when registering a dopplerogram above it:
- 55-60% - on the spectrogram - filling of the spectral window, the maximum speed is not changed or increased;
- 60-75% - filling the spectral window, increasing the maximum speed, expanding the envelope contour;
- 75-90% - filling of the spectral window, flattening of the velocity profile, increase in LCS. Reverse flow possible;
- 80-90% - the spectrum approaches a rectangular shape. "Stenotic wall";
- > 90% - the spectrum approaches a rectangular shape. Possible decrease in LSC.
When occluded by atheromatous masses in the lumen of the affected vessel, bright, homogeneous masses are revealed, the contour merges with the surrounding tissues. On the dopplerogram below the level of the lesion, a collateral type of blood flow is detected.
Aneurysms are detected by scanning along the vessel. The difference in the diameter of the expanded area by more than 2 times (at least 5 mm) compared with the proximal and distal sections of the artery gives grounds for establishing an aneurysmal expansion.
Doppler criteria for occlusion of the arteries of the brachycephalic system
Stenosis of the internal carotid artery. Carotid Dopplerography with a unilateral lesion reveals a significant asymmetry of blood flow due to a decrease in it from the side of the lesion. With stenosis, an increase in the velocity Vmax due to the turbulence of the flow is revealed.
Occlusion of the common carotid artery. Carotid Doppler sonography reveals the absence of blood flow in the CCA and ICA on the side of the lesion.
Stenosis of the vertebral artery. With a unilateral lesion, an asymmetry of the blood flow velocity of more than 30% is detected, with a bilateral lesion, a decrease in the blood flow velocity below 2-10 cm/sec.
Occlusion of the vertebral artery. Lack of blood flow at the location.
Doppler criteria for occlusion of arteries of the lower extremities
Dopplerographic assessment of the state of the arteries of the lower extremities analyzes the Dopplerograms obtained at four standard points (projection of the Scarpov triangle, 1 transverse finger medial to the middle of the Pupartite ligament, the popliteal fossa between the medial malleolus and the Achilles tendon on the back of the foot along the line between the 1st and 2nd fingers) and the indices of the regional pressure (upper third of the thigh, lower third of the thigh, upper third of the lower leg, lower third of the lower leg).
Occlusion of the terminal aorta. In all standard points on both limbs, collateral-type blood flow is recorded.
Occlusion of the external iliac artery. At standard points on the side of the lesion, collateral blood flow is recorded.
Occlusion of the femoral artery in combination with damage to the deep femoral artery. In the first standard point on the side of the lesion, the main blood flow is recorded, in the rest - collateral.
Popliteal artery occlusion- in the first point, the blood flow is main, in the rest - collateral, while the RID on the first and second cuffs is not changed, on the rest it is sharply reduced (see Fig. rice. four).
When the leg arteries are affected, the blood flow is not changed at the first and second standard points, while at the third and fourth points it is collateral. RID is not changed on the first or third cuffs and sharply decreases on the fourth.
Diseases of the peripheral veins
Acute occlusive thrombosis. In the lumen of the vein, small dense, homogeneous formations are determined that fill its entire lumen. The reflection intensity of different sections of the vein is uniform. With a floating thrombus of the veins of the lower extremities in the lumen of the vein - a bright, dense formation, around which there is a free area of the lumen of the vein. The top of the thrombus has a large reflectivity, makes oscillatory movements. At the level of the apex of the thrombus, the vein expands in diameter.
Valves in the affected vein are not determined. An accelerated turbulent blood flow is recorded above the top of the thrombus.
Valvular insufficiency of the veins of the lower extremities. When conducting tests (Valsalva test in the study of the femoral veins and the great saphenous vein, compression test in the study of the popliteal veins), a balloon-shaped expansion of the vein below the valve is detected, with Doppler ultrasound a retrograde wave of blood flow is recorded. A retrograde wave lasting more than 1.5 seconds is considered hemodynamically significant (see Fig. 5-8). From a practical point of view, a classification of the hemodynamic significance of retrograde blood flow and the corresponding valvular insufficiency of the deep veins of the lower extremities was developed (Table 7).
Post-thrombotic disease
When scanning a vessel in the recanalization stage, a thickening of the vein wall up to 3 mm is detected, its contour is uneven, the lumen is heterogeneous. When conducting tests, an expansion of the vessel by 2-3 times is observed. Doppler sonography reveals monophasic blood flow ( rice. 9). When conducting tests, a retrograde wave of blood is detected.
We examined 734 patients aged 15 to 65 years (average age 27.5 years) using Doppler sonography. In a clinical study according to a special scheme, signs of vascular pathology were revealed in 118 (16%) people. When conducting a screening ultrasound study, peripheral vascular pathology was first detected in 490 (67%), of which 146 (19%) were subject to dynamic observation, and 16 (2%) people required additional examination in an angiological clinic.
Rice. 1 Longitudinal scan of an artery. Main type of blood flow.
Rice. 2 Examination of blood flow in a vein using color doppler and Doppler in a pulsed mode.
Rice. 3 Variant of normal blood flow in a vein. Research in the mode of a pulse dopplerography.
| Rice. four Standard approaches for Doppler sonography of peripheral vessels. Levels of imposition of compression cuffs in the measurement of regional SBP. | |
|
1 - aortic arch; 2, 3 - vessels of the neck: OSA, VSA, NSA, PA, JV; 4 - subclavian artery; 5 - shoulder vessels: brachial artery and vein; 6 - vessels of the forearm; 7 - vessels of the thigh: BOTH, PBA, GBA, corresponding veins; 8 - popliteal artery and vein; 9 - posterior b / tibial artery; 10 - dorsal artery of the foot. МЖ1 - upper third of the thigh; |
Rice. 5 Variants of hemodynamically insignificant retrograde blood flow in the deep veins of the lower extremities during functional tests. The duration of the retrograde current is less than 1 sec in all cases (normal blood flow in the vein is below the 0-line, retrograde blood flow is above the 0-line).
Rice. 6 A variant of hemodynamically insignificant retrograde blood flow in the femoral vein during a strain test [a retrograde wave lasting 1.19 seconds above the isoline (H-1)].
Rice. 7 Variant of hemodynamically significant retrograde blood flow in the deep veins of the lower extremities (the duration of the retrograde wave is more than 1.5 sec).
Rice. 8 A variant of hemodynamically significant retrograde blood flow in the vein of the lower extremities (the duration of the retrograde wave is more than 2.30 sec).
Rice. 9 Blood flow in a vein in a patient after thrombophlebitis.
| Table 1 Average indicators of the linear velocity of blood flow for different age groups in the vessels of the brachycephalic system, cm/sec, normal (according to Yu.M. Nikitin, 1989). | ||||||
| Artery | 20-29 years old | 30-39 years old | 40-48 years old | 50-59 years old | > 60 years old | |
| Left OCA | 31,7+1,3 | 25,6+0,5 | 25,4+0,7 | 23,9+0,5 | 17,7+0,6 | 18,5+1,1 |
| Right OCA | 30,9+1,2 | 24,1+0,6 | 23,7+0,6 | 22,6+0,6 | 16,7+0,7 | 18,4+0,8 |
| Left vertebral | 18,4+1,1 | 13,8+0,8 | 13,2+0,5 | 12,5+0,9 | 13,4+0,8 | 12,2+0,9 |
| Right vertebral | 17,3+1,2 | 13,9+0,9 | 13,5+0,6 | 12,4+0,7 | 14,5+0,8 | 11,5+0,8 |
| table 2 Indicators of the linear velocity of blood flow, cm / sec, in healthy individuals, depending on age (according to J. Mol, 1975). | |||||
| Age, years | Vsyst OSA | VoiastOCA | Vdiast2 OSA | Vsyst PA | Vsyst of the brachial artery |
| Up to 5 | 29-59 | 12-14 | 7-23 | 7-36 | 19-37 |
| To 10 | 26-54 | 10-25 | 6-20 | 7-38 | 21-40 |
| up to 20 | 27-55 | 8-21 | 5-16 | 6-30 | 26-50 |
| up to 30 | 29-48 | 7-19 | 4-14 | 5-27 | 22-44 |
| up to 40 | 20-41 | 6-17 | 4-13 | 5-26 | 23-44 |
| Up to 50 | 19-40 | 7-20 | 4-15 | 5-25 | 21-41 |
| Up to 60 | 16-34 | 6-15 | 3-12 | 4-21 | 21-41 |
| >60 | 16-32 | 4-12 | 3-8 | 3-21 | 20-40 |
| Table 3 Indicators of blood flow in the main arteries of the head and neck in practically healthy individuals. | |||||||
| Vessel | D, mm | Vps, cm/sec | Ved, cm/s | TAMX, cm/sec | TAV, cm/s | R.I. | PI |
| 5,4+0,1 | 72,5+15,8 | 18,2+5,1 | 38,9+6,4 | 28,6+6,8 | 0,74+0,07 | 2,04+0,56 | |
| 4,2-6,9 | 50,1-104 | 9-36 | 15-46 | 15-51 | 0,6-0,87 | 1,1-3,5 | |
| 4,5+0,6 | 61,9+14,2 | 20.4+5,9 | 30,6+7,4 | 20,4+5,5 | 0,67+0,07 | 1,41+0,5 | |
| 3,0-6,3 | 32-100 | 9-35 | 14-45 | 9-35 | 0,5-0,84 | 0,8-2,82 | |
| 3,6+0,6 | 68,2+19,5 | 14+4,9 | 24,8+7,7 | 11,4+4,1 | 0,82+0,06 | 2,36+0,65 | |
| 2-6 | 37-105 | 6,0-27,7 | 12-43 | 5-26 | 0,62-0,93 | 1.15-3,95 | |
| 3,3+0,5 | 41,3+10,2 | 12,1+3,7 | 20,3+6,2 | 12,1+3,6 | 0,7+0,07 | 1,5+0,48 | |
| 1,9-4,4 | 20-61 | 6-27 | 12-42 | 6-21 | 0,56-0,86 | 0,6-3 | |
| Table 4 Average indicators of blood flow velocity in the arteries of the lower extremities obtained during examination of healthy volunteers. | |
| Vessel | Peak systolic velocity, cm/s, (deviation) |
| External iliac | 96(13) |
| Proximal segment of the common femur | 89(16) |
| Distal segment of the common femur | 71(15) |
| Deep femoral | 64(15) |
| Proximal segment of the superficial femur | 73(10) |
| Middle segment of the superficial femur | 74(13) |
| Distal segment of the superficial femur | 56(12) |
| Proximal segment of the popliteal artery | 53(9) |
| Distal segment of the popliteal artery | 53(24) |
| Proximal segment of the anterior b/tibial artery | 40(7) |
| Distal segment of the anterior b/tibial artery | 56(20) |
| Proximal segment of the posterior b/tibial artery | 42(14) |
| Distal segment of the posterior b/tibial artery | 48(23) |
| Table 5 Parameters of quantitative assessment of dopplerograms of the arteries of the lower extremities are normal. | |||||
| Artery | Vpeak(+) | Vpeak(-) | Vmean | Tas | Tas(-) |
| General femoral | 52,8+15,7 | 130,7+5,7 | 9,0+3,7 | 0,11+0,01 | 0,16+0,03 |
| Popliteal | 32,3+6,5 | 11,4+4,1 | 4,1+1,3 | 0,10+0,01 | 0,14+0,03 |
| Back w / tibial | 20,4+6,5 | 7,1+2,5 | 2,2+0,9 | 0,13+0,03 | 0,13+0,03 |
| Table 6 Indicators IRSD and RID. | ||
| Cuff level | IRCP,% | RID |
| Distal section of the superficial femoral artery | 118,95-0,83 | 1,19 |
| Distal deep femoral artery | 116,79-0,74 | 1,17 |
| Popliteal artery | 120,52-0,98 | 1,21 |
| Distal anterior b/tibial artery | 106,21-1,33 | 1,06 |
| Distal posterior b/tibial artery | 107,23-1,33 | 1,07 |
| Table 7 Hemodynamic significance of retrograde blood flow in the study of deep veins of the lower extremities. | ||
| Degree | Characterization of hemodynamic significance | signs |
| H-0 | No valvular insufficiency | When conducting tests on the Dopplerogram, there is no retrograde current |
| H-1 | Hemodynamically insignificant deficiency. Surgical correction is not indicated | When conducting tests, a retrograde blood flow is recorded with a duration of no more than 1.5 seconds (Fig. 5.6) |
| H-2 | Hemodynamically significant valvular insufficiency. Surgical correction indicated | Retrograde wave duration> 1.5 sec (Fig. 7.8) |
Conclusion
In conclusion, we note that the ultrasonic scanners of the Medison company meet the requirements of screening examinations of patients with pathology of peripheral vessels. They are most convenient for departments of functional diagnostics, especially the polyclinic level, where the main streams of primary examinations of the population of our country are concentrated.
Literature
Unpleasant sensations in the legs sooner or later force us to see a doctor to find out the causes of swelling, pain, heaviness and night cramps. In each case, in addition to the examination, we are invited to undergo a bridle of the lower extremities. What is this procedure and what diseases can be diagnosed with it?
What is ultrasound and what is examined with its help
Doppler ultrasound is an abbreviation for the name of one of the most informative methods for studying blood circulation in the vessels - Doppler ultrasound. Its convenience and speed, coupled with the absence of age-related and special contraindications, make it the "gold standard" in the diagnosis of vascular diseases.
The ultrasound procedure is performed in real time. With its help, the specialist already after 15-20 minutes receives sound, graphic and quantitative information about the blood flow in the venous apparatus of the legs.
The following are being researched:
- Great and small saphenous veins;
- inferior vena cava;
- iliac veins;
- femoral vein;
- Deep veins of the leg;
- Popliteal vein.
When performing ultrasound of the lower extremities, the most important parameters of the state of the vascular walls, venous valves and the patency of the vessels themselves are evaluated:
- The presence of inflamed areas, blood clots, atherosclerotic plaques;
- Structural pathologies - tortuosity, kinks, scars;
- Expression of vascular spasms.
During the study, the compensatory possibilities of blood flow are also evaluated.
When is a Doppler Study Necessary?
The urgent problems in blood circulation make themselves felt in varying degrees of severe symptoms. You should hurry to the doctor if you begin to notice difficulties with putting on shoes, and your gait is losing its lightness. Here are the main signs by which you can independently determine the likelihood that you have a violation:
- Soft swelling of the feet and ankle joints, appearing in the evening and completely disappearing by morning;
- Discomfort when moving - heaviness, pain, rapid fatigue of the legs;
- Convulsive twitching of legs during sleep;
- Rapid freezing of the legs at the slightest drop in air temperature;
- Cessation of hair growth on the shins and thighs;
- Feeling of skin prickling.
If you do not consult a doctor when these symptoms appear, then in the future the situation will only worsen: varicose nodes, inflammation of the affected vessels and, as a result, trophic ulcers will appear, which already threatens with disability.
Vascular diseases diagnosed by ultrasound
Since this type of study is one of the most informative, the doctor, based on its results, can make one of the following diagnoses:
Any of the diagnoses made requires the most serious attitude and immediate treatment, since the above diseases cannot be cured by themselves, their course only progresses and eventually causes severe consequences up to complete disability, in some cases even death.
How is a Doppler study performed?
The procedure does not require preliminary preparation of patients: there is no need to follow any diet, take drugs other than those that you usually take to treat existing diseases.
Arriving for an examination, you need to remove all jewelry and other metal objects from yourself, provide the doctor with access to the shins and thighs. The doctor of ultrasound diagnostics will offer to lie down on the couch and apply a special gel to the sensor of the device. It is the sensor that will capture and transmit all signals about pathological changes in the vessels of the legs to the monitor.
The gel improves not only the glide of the sensor over the skin, but also the speed of data transmission obtained as a result of the study.
After the examination is completed in a prone position, the doctor will offer to stand on the floor and continue to study the state of the vessels to obtain additional information about the suspected pathology.
Normal values during ultrasound examination of the lower extremities
Let's try to deal with the results of the study of the lower arteries: the uzdg has its own normal values, with which you just need to compare your own result.
Numerical values
- ABI (ankle-brachial complex) - the ratio of ankle blood pressure to shoulder blood pressure. The norm is 0.9 and above. An indicator of 0.7-0.9 speaks of arteries, and 0.3 is a critical figure;
- Limit in the femoral artery - 1 m / s;
- The limiting speed of blood flow in the lower leg is 0.5 m/s;
- Femoral artery: resistance index - 1 m/s and above;
- Tibial artery: pulsation index - 1.8 m/s and above.
Types of blood flow
They can be designated as follows: turbulent, main or collateral.
Turbulent blood flow fixed in places of incomplete vasoconstriction.
Main blood flow is the noma for all large vessels - for example, the femoral and brachial arteries. The note "main altered blood flow" indicates the presence of stenosis above the study site.
Collateral blood flow is registered below the places where there is a complete absence of blood circulation.
The presence of a central venous catheter can cause an upper limb deep vein thrombus (DVT). Ultrasound of the veins of the upper extremities in the mode of scanning, compression and Dopplerography is a safe and reliable method for diagnosing deep vein thrombosis.
Rice. one. Longitudinal section of the right brachial vein (RT BRACH V). Pay attention to the significant length of the doubled vein in the area close to the axillary zone (arrow).
The superficial venous system of the VC is represented by two main trunks: the lateral saphenous vein (vena cefalica), which runs along the radial side of the arm, and the medial saphenous vein (vena basilica), which runs along the ulnar surface (see Fig. 2). These veins anastomose in the elbow area with the help of the intermediate vein of the elbow (V. intermediacubiti). The medial saphenous vein runs along the inner surface of the forearm, along m. Flexor carpi ulnaris, from the hand to the armpit, where it flows into the axillary vein. A feature of the medial saphenous vein is that at the border of the lower and middle third of the shoulder, it penetrates from the subcutaneous position into the deep fascia of the shoulder. The lateral saphenous vein originates from the outer surface of the hand, continues along the outer surface of the forearm and shoulder, at the level of the lateral side of the biceps, and flows into the brachial vein in the upper third of the shoulder. Other venous ducts of the shoulder area and the lateral part of the chest empty into the axillary vein. After passing the first rib, the axillary vein continues as the subclavian vein. The subclavian vein joins with the internal jugular vein to form the brachiocephalic vein. The right and left brachiocephalic veins join to form the superior vena cava, which then empties into the right atrium (see Figure 3).
Rice. 2. Anatomy of the superficial veins of the upper limb.
Rice. 3. Anatomy of the veins of the upper shoulder girdle. Due to their proximity to the right atrium, these veins require constant monitoring of the cardiac phasing of the blood flow.
An important feature that distinguishes deep-seated veins from superficial ones is that the former run parallel to the corresponding arteries (see Fig. 4A, B). Superficial veins run independently of the arterial system.
Rice. four.(A) Longitudinal section of the left brachial artery and vein. The fact that an artery and a vein run together indicates that they belong to the deep vein system. (B) Longitudinal section of the middle part of the arm. Brachial artery of another patient with two adjacent veins. The doubling of the veins causes difficulties in diagnosing thrombosis. Identification of one compressed vein near an artery may mask the presence of a thrombus in another vein.
Perforating veins run between the superficial and deep venous systems of the forearm and upper arm, forming important collateral pathways in the presence of thrombosis. In the absence of thrombosis, they are usually not visible due to their small size, but these veins may increase in diameter when they are involved in draining blood from a blocked vessel (see Fig. 5).
Rice. 5. This brachial vein, partially occluded by a thrombus (arrow), shows a strip of a peripheral catheter (PC). The dilated perforator vein (blue) connects to the brachial vein, restoring blood flow to the affected area (red).
A feature of the veins of the VC is the presence of valves in their lumen. Moving peripherally, it is noticeable that the location of the first valve changes quite often, but it is usually located in the proximal brachial vein. The leaflets of the valves should be thin and move depending on the direction of blood flow. The valve leaflets should be relatively echogenic (see Figure 6).
Rice. 6. Normal valves in veins. Pay attention to the thin leaflets, which are in the open position at this phase of the blood flow. Note the anechoic space outside the valve without a thrombus (arrows).
SCAN TECHNIQUE
Ultrasound examination of the veins of the VC for the presence of DVT is based on similar principles that are used in the venous examination of the lower extremities: scanning, compression and Doppler sonography.
The examination is usually performed with the patient in a horizontal position and the arm in a neutral anatomical position. The arm should be partially abducted to the side to be able to view the axillary vein. If the arm is fully abducted, the axillary vein may collapse as it passes between the clavicle and the first rib.
A linear probe is used to conduct the survey. A transducer frequency between 7 and 12 MHz is normal to start the examination, as it provides sufficient penetration, especially for large and swollen hands. The high frequency transducer can be used for superficial veins or thin arms. It is important to make sure that the doppler is set to the slower blood flow that is typical for veins.
The standard vascular compression procedure is used throughout the arm and neck, for superficial and deep veins (see Figure 7). However, this method cannot be used for subclavian and central veins, given their anatomical location.
Rice. 7. Cross section of the vessels of the upper limb under the armpit. The axillary and medial saphenous veins of the arm (V) are clearly visible in the picture on the left. On the right, after compression, only the artery is visible (A). The veins are subjected to compression up to the complete disappearance of the lumen, effectively eliminating the presence of a blood clot.
The thrombus can be directly seen in the lumen of the vein. It looks like an echogenic conglomerate fixed to the vascular wall. Light pressure of the sensor leads to compression of the lumen of a normal vein, which does not occur if there is a thrombus in it. Compression should be light because fresh clots are soft and jelly-like in texture. Strong pressure can cause such a degree of compression that it will erroneously indicate the patency of the vessel. Compression should be performed in a transverse section, because if it is carried out in a longitudinal section, the occluded vein may disappear due to its going beyond the scanning plane, and not due to compression. Another reason for scanning in cross section is the ability to more accurately identify paired veins.
Color Doppler is an effective auxiliary method for confirming the patency of a vein. The entire wide lumen of the vein should be fully color-coded (see Fig. 8). During a color Doppler scan, a physiological fluctuation in the direction of blood flow is recorded in the large central veins. Due to the contraction of the right atrium, the a-wave follows back into the venous bed, causing a temporary reverse type of blood flow. If the freeze frame shows a short moment of passage of the reverse a-wave, this file should not be archived.
Rice. eight. Longitudinal section of the jugular vein. The cavity of this vein is completely sketched in color, excluding the presence of a thrombus.
To enhance the color signal in veins with slow flow or in veins with a narrowed lumen, the patient can be asked to perform a Valsalva maneuver. Deep inspiration increases intrathoracic pressure, which limits the return of venous blood to the heart, causing a decrease in cardiac output, which leads to a temporary stagnation of venous blood in the periphery.
Subsequently, the patient is asked to exhale and close the palm into a fist. Compression is also applied to the vessels of the forearm. The compression must be fast and sufficient to push the blood through the veins. As a result, there is an additional return of blood to the venous system, which will lead to an increase in the received Doppler signal. When conducting a Doppler examination in large veins, aliasing can occur - an effect when the color scale of the device is set to a velocity range that does not correspond to the blood flow velocity in the examined veins.
This results in unwanted areas of Doppler color change (see Fig. 9). When the device is set to record blood flow in the vessel at a higher rate, it can be found that there is no visualization of slow laminar blood flow along the wall (see Fig. 10). Such an image can be misinterpreted; you need to be careful not to confuse this artifact with a clot attached to the wall.
Rice. 9. Longitudinal image of the brachial vein with Doppler color scale adjusted to a lower range of the velocity scale than in the vein. Pay attention to the color change in the center of the vessel, this is due to the aliasing effect, which should not be confused with a change in the direction of blood flow.
Rice. ten. Color Doppler image of the brachial vein with the color scale adjusted to a higher range of the velocity scale. Please note that only the central segment with a high velocity of blood passing through the middle of the vessel is indicated by color. The zone along the walls is NOT drawn (arrows), this is an artifact that should not be confused with a thrombus near the walls.
The blood flow profile in the spectral Doppler mode can be of great diagnostic value in the study of the veins of the upper extremities. Due to the fact that the VC veins are close to the heart, the registration of a pronounced phase of blood flow from the ASVD shape curve is a normal phenomenon. The presence of pronounced phasing of the blood flow convinces us that the patency of the channel between the point of Doppler observation and the right atrium is satisfactory. Its absence, on the contrary, indicates the presence of a thrombus in the central veins, which may not be visualized due to anatomical features (the presence of a lung and bone structures that prevent its visualization).
Rice. eleven. Inspection of the jugular vein using spectral dopplerography. The curve corresponds to the cardiac cycle, in particular the activity in the right atrium. During atrial contraction, a short reverse flow appears - wave A, followed by a rapid antegrade flow into the empty right atrium. When the right atrium is filled, the blood flow slows down, the S wave is recorded. Later, the tricuspid valve opens and the antegrade blood flow fills the right ventricle at a high speed, which is designated as the D-wave. Then the blood flow velocity decreases until the ventricle is completely filled: D-wave. Visualization of this curve guarantees the patency of the channel between the point of observation and the right atrium.
THROMBOSIS OF THE VEINS OF THE UPPER LIMB AND THE JUGULAR VEIN
The principles that are used to examine DVT of the lower extremities apply similarly to the veins of the upper extremity and neck. Insufficient lumen reduction during compression of the veins of the arm and neck and/or lack of flow on color or power Doppler are diagnostic criteria for thrombosis (see Fig. 12). Larger, more proximal veins, such as the axillary and subclavian veins, do not lend themselves to compression due to their location; therefore, the diagnosis of thrombosis in these vessels depends on careful Doppler examination. Among the indirect symptoms of thrombosis, one can distinguish the loss of vibration of the vein wall, which is associated with the phases of respiration and heart rate, indicating proximal vein occlusion; such symptoms are important if a possible diagnosis of central vein thrombosis (brachiocephalic or superior vena cava) is suspected. The phasing associated with breathing and heart rate can be altered by asking the patient to take a deep breath, hold the breath, or perform the Valsalva maneuver. The absence of an antegrade blood flow wave after expiration during the Valsalva maneuver indicates the presence of a thrombus in the central vein. Comparison with blood flow on the opposite side can help determine the level of thrombosis.
Rice. 12. Cross section of vessels near the left armpit. On the image of the axillary vein, which was not subject to compression, echogenic formations are visible. When compressed (arrow), the walls cannot converge due to blockage by a thrombus. But, despite the fact that this is a relatively fresh thrombus, it undergoes partial compression.
DIAGNOSTICS OF DEEP VEIN THROMBOSIS
The lumen of a normal vein is anechoic and should be completely filled in on a color Doppler image, especially when blood flow is increased. The thrombus is visualized as immovable echogenic material in the lumen of the vessel (see Fig. 13). Color Doppler shows no blood flow in the affected area (see Fig. 14). Despite the fact that the newly formed thrombus is relatively hypoechoic, echogenicity increases during the development of the ego. In addition, a fresh thrombus is characterized by an expansion of the vein, which becomes more rounded in comparison with the norm. Ideal for diagnosing i>
Rice. 13. Image of the medial saphenous vein of the right arm. Note the relatively dilated lumen filled with echogenic thrombus (arrows).
A fresh thrombus does not adhere tightly to the vascular wall, so in the color Doppler picture, you can see the blood flow along the periphery of the clot (see Fig. 14). An older thrombus becomes more echogenic, adheres tightly to the vascular wall, becomes more organized and fibrous, causing the vein to become a relatively small echogenic structure that is difficult to detect. It is common for a thrombus to spread to one of the walls of the vein, which leads to the appearance of an asymmetric filling of the vessel lumen with color in color Doppler imaging. In patients with chronic thrombosis, a new thrombus may overlap the previous one, and a mass of different echogenicity can be seen in the lumen of the vessel (see Fig. 15).
Rice. fourteen.(A) Relatively fresh hypoechoic thrombus in the lumen of the subclavian vein. However, the presence of blood flow is visible, which passes between the thrombus and the vessel wall (arrow). The best way to check for this symptom is to exhale, during a Valsvalva test, or by compressing the vascular wall. (B) The edge of a thrombus is defined as a filling defect in the lumen of the subclavian vein (arrow). Pay attention to how in the color Doppler picture the area around the clot is filled with color.
Rice. fifteen. Within this vein is a thrombus (curly bracket). Pay attention to the mixed echostructure associated with the layering of fresh thrombi on previous ones.
Usually the blood in the vessel is anechoic. Individual red blood cells (E) are too small to reflect the ultrasonic wave. However, under certain conditions, E can stick together to each other. Such groups E are called "coin column of erythrocytes" (see Fig. 16). Causes that lead to it include infections, multiple myeloma, diabetes, cancer, and pregnancy. The “coin column of erythrocytes” becomes a rather large obstacle and reflects ultrasonic waves, as a result of which, during an ultrasound examination, we observe the presence of echo-positive inclusions in the lumen of the vessel. Such inclusions are more often observed in areas with slow blood flow, especially in the cavity behind the vessel valve leaflets (see Fig. 17). If during the compression of the vessel in the area of the valve we observe a slight displacement of this conglomerate, it can be argued about the "formation of coin columns". However, if the echogenic material does not move after compression, an early stage of thrombus formation is diagnosed (see Figure 18).
Rice. 16. Micrograph of red blood cells. Pay attention to several groups of repeaters, which, when combined, become similar in shape to lifebuoys. When grouped, they can reflect ultrasonic waves, allowing visualization of non-thrombotic blood (Magnification × 30).
Rice. 17. Valve leaflets in a vein. Note that there is echogenic material behind the deeper leaflet (arrow). With compression, it was easy to get rid of it. This symptom indicates the formation of a "column of erythrocytes" in the zone of slow blood flow.
Rice. eighteen. Valve leaflets in a vein. Note that there is echogenic material both behind and outside the deep leaflet (arrows). It was not possible to get rid of it with the help of compression. This is a fresh thrombus that begins to form behind the valve leaflet and spreads along the vessel wall.
SYMPTOMS DETECTED WITH SPECTRAL DOPPLER
Spontaneous blood flow and respiratory fluctuations
Rice. 19. The spectral Doppler image of the dilated vein shows relatively little blood flow during breath holding during the Valsalva maneuver. However, on expiration there is a slight rise in the antegrade flow, indicating the presence of thrombosis in the central vein. Also note that there is no synchronization with the cardiac cycle.
Compression
Normal venous blood flow is slow. The quality of its display on the Doppler image can be improved by using compression distal to the examination site (see Fig. 20). In a normal venous system, after compression, there is a rapid increase and decrease in blood velocity, while in the presence of a thrombus, there will be little or no response to compression (see Fig. 21). Compression should be moderate, as there is a risk of displacement of fresh fragile thrombi, which can lead to pulmonary embolism. However, the risk of its occurrence is small, and the reports of such cases are few.
Rice. twenty. Longitudinal section of a normal, intact brachial vein. The spectral Doppler image shows relatively laminar blood flow. However, a slight compression causes a sharp increase in velocity, which leads to the appearance of an aliasing effect, which indicates the normal state of the vascular wall. The veins of the upper limb are characterized by slow blood flow. To speed up blood flow, the patient should exercise the forearm by repeatedly squeezing the towel in the fist. This exercise increases metabolism, thus improving blood circulation.
Rice. 21. Spectral Doppler image of the right subclavian vein, in the area close to the brachiocephalic vein. Despite sufficient filling of the vein cavity with blood, we observe a reduced laminar flow, asynchronous with the phases of respiration (monophasic). When performing compression (Aug), a slight acceleration of blood movement is noticeable, which makes it possible to confirm the presence of a thrombus in the vein.
Blood flow in collateral vessels
When the main veins become blocked, blood may be seen in the collateral veins. At the initial stage, the collateral vessels will still be dilated, but increased velocity and blood flow are noticeable. After a few weeks, the collateral vessels increase in diameter and are displayed on the screen during a color Doppler examination (see Fig. 5). That is why their appearance indicates the presence of chronic thrombosis.
The collateral veins themselves can serve as guides for the spread of a thrombus from superficial to deep systems (see Fig. 22). This feature is important in the diagnosis of thrombophlebitis. Deep thrombophlebitis gives a worse prognosis and often requires invasive treatments.
Rice. 22.(A) An echogenic thrombus is seen in the collateral vein (arrows). When it flows into a deep vein, the thrombus (C) increases, clogging the lumen of the larger vein. (B) Longitudinal section showing a main vein filled with an echogenic thrombus (down arrows). In the proximal zone, its deepening and the spread of the thrombus to the axillary vein are noticeable (arrow up). It is a thin, palpable vessel with a clinical diagnosis of superficial thrombophlebitis. The fact that the infected thrombus has entered the deep venous system makes therapy difficult.
Chronic changes after DVT
Intact valves move gently with blood flow (see Figure 6). If the valve leaflets are rigid or fixed, this usually indicates complications from DVT.
The walls of a normal vein are smooth and thin. Due to the restoration of vascular patency after DVT, the walls become uneven, thicken and have increased echogenicity. Sometimes calcification of the vascular wall may develop.
Thrombosis, which occurs as a result of therapy with an indwelling venous catheter, has certain characteristics. The clot may spread along the catheter, or attach to the tip (see Fig. 23). If the catheter is fixed proximal to the right atrium, such as within the superior vena cava or brachiocephalic vein, a thrombus may develop and spread, obstructing venous flow. If the thrombus is localized in the central veins, its visualization using the B-mode is impossible, so the use of Doppler is necessary. In the large veins of the upper shoulder girdle (subclavian and jugular vein) throughout the entire length, when conducting a spectral Doppler study, we observe the ASVD curve. If the large central veins of the upper body (subclavian and jugular) are wide, the blood trunk between these vessels and the right atrium should transmit the ASVD curve.
However, if Doppler reflects slow flow in the vein and retrograde flow is also observed, this indicates the presence of a central thrombus (see Fig. 24). If these symptoms are found in both the right and left subclavian and jugular veins, the level of obstruction is the vena cava. But, if such changes are detected only on one side, the location of thrombosis is at the level of the brachiocephalic vein.
Rice. 23. A catheter is visible in the left subclavian vein (arrow). In the lumen of the vessel, an echogenic thrombus clot (C) is connected to the tip of the catheter.
Rice. 24. Color and spectral Doppler image of the right subclavian vein. The blood flow is seen in the center, but on the spectral image it is shown as relatively slow and does not correspond to cardiac phases. This symptom indicates the presence of a thrombus in the central vein at the level of the right brachiocephalic or vena cava.
Clinical Significance
Baarslag and colleagues compared Doppler ultrasound and venography in the diagnosis of upper limb DVT and found 82% sensitivity and 82% specificity. These studies showed that 63% of patients diagnosed with thrombosis were also diagnosed with malignant diseases, and in 14% the cause was the introduction of an indwelling central catheter.
The risk of clinically significant pulmonary embolism due to DVT in the upper extremities is relatively small compared with DVT in the lower extremities, but the incidence of such events is constantly variable. Mustafa et al found that 65 patients with upper limb vein thrombosis had no symptoms of pulmonary embolism.
Bernardi and colleagues found that approximately 10% of cases of venous thrombosis can be diagnosed with DVT. Despite the fact that risk factors are well defined, in 20% of patients the occurrence of DVT has no explanation. Bernardi and colleagues reported that up to one-third of patients diagnosed with DVT may develop pulmonary embolism, emphasizing that DVT should not be considered a rare and harmless occurrence.
In contrast, Kommareddy and colleagues determined that DVT was diagnosed in only about 1-4% of all DVT cases. However, these investigators noted that unclear or recurrent DVT should prompt an aggressive search for coagulation disorders or underlying malignancy.
Levy and colleagues reported that the incidence of pulmonary embolism associated with previously diagnosed DVT is relatively small (approximately 1%). Anticoagulant therapy is better suited to treat manifestations of DVT, but does not reduce the risk of pulmonary embolism. Given that patients diagnosed with DVT usually feel very ill, the associated risk of anticoagulant therapy should be given great attention.
However, Hingorani and colleagues followed a large group of patients diagnosed with DVT and found that overall mortality rates were as high as 30%. But only 5% of this group developed pulmonary embolism. The death of most of the patients was caused by comorbidities, which had a greater effect on mortality than pulmonary embolism. That is why large rates of death from DVT can be associated with hidden features in the progression of the disease of each individual patient, while not being a direct consequence of DVT itself.
CONCLUSIONS
Ultrasonography is a safe and reliable method for identifying a possible diagnosis of DVT in symptomatic patients. A cancer patient with a swollen arm and a permanent IV catheter is an ideal candidate for this study. However, the immediate risk of possible occurrence of pulmonary embolism in these patients still needs to be accurately determined.
