Swelling of the arm: arteries and veins at once
When the arm swells, turns blue and hurts, the cause is almost always venous, but a complete examination also includes the arteries - otherwise you may miss compression syndrome, in which both channels are compressed at the same time. Therefore, if the symptoms are unclear, it is logical to scan the entire vascular bed of the arm in one go.
Deep vein thrombosis of the upper extremity is less common than in the legs, but its incidence is increasing due to the widespread use of subclavian catheters, port systems and pacemaker leads. This catheter-associated thrombosis is manifested by edema, a feeling of fullness, and dilation of the saphenous veins in the shoulder and chest wall. Ultrasound detects it with a compression test: the thrombosed vein is not compressed by the sensor, and echogenic masses are visible in the lumen.
A separate form is force thrombosis, Paget-Schrötter syndrome, which develops in young physically active people after intense stress on the shoulder girdle. It is based on chronic compression of the subclavian vein in the narrow costoclavicular space. The diagnosis requires not only the identification of a blood clot, but also positional compression tests, as well as mandatory comparison with the healthy side - which makes the examination of both arms the standard in this situation.
What does duplex scanning show?
The method combines conventional ultrasound imaging of a vessel with analysis of the blood flow in it. The wall of the artery and vein, the thickness of the intima-media complex, atherosclerotic plaques with an assessment of their structure and the degree of narrowing of the lumen, blood clots, aneurysms, tortuosity and pathological anastomosis are visible.
Spectral analysis translates this into numbers: peak systolic velocity, end-diastolic velocity, resistance indices. They are used to calculate the percentage of stenosis - an indicator that determines whether conservative treatment is sufficient or intervention is required.
Functional tests
Some vascular pathology appears only during exercise. Compression tests detect thrombosis: a healthy vein is completely compressed by the sensor, a thrombosed one is not. The Valsalva maneuver shows the incompetence of the venous valves and reflux underlying varicose veins.
Positional tests are used when compression syndromes are suspected, when a vessel is compressed by muscles, ligaments or an additional rib in a certain position of the limb. At rest the picture is normal.
Advantages over other methods
Duplex scanning does not require contrast or radiation, so it can be repeated as often as necessary, including in cases of renal failure and allergies to iodine-containing drugs, where contrast angiography is contraindicated.
Operator-dependent method: the result depends significantly on the experience of the doctor and the quality of the device. Therefore, when making fundamental decisions, for example, before vascular surgery, the study is often repeated or supplemented with computed angiography.