What is a significant indicator of venous thromboembolism in Doppler ultrasound?

The significant indicator of venous thromboembolism in Doppler ultrasound is the absence of venous compressibility. In a healthy vein, when pressure is applied, the vein should easily compress, indicating that it is not obstructed by a clot. However, in cases of venous thromboembolism, the presence of a thrombus within the vessel prevents it from compressing, which serves as a critical sign for diagnosis. The inability to compress the vein in the presence of applied pressure suggests that there is a blockage, which is often associated with deep vein thrombosis (DVT).

Increased venous flow may suggest adequate venous return and is not typically indicative of thromboembolism. A constant venous diameter does not provide sufficient information about the presence of a thrombus, as veins can vary in size due to numerous factors unrelated to thrombosis. Visible varicosities, while they can indicate issues with venous health, do not specifically confirm the presence of a thrombus and can occur due to chronic venous insufficiency rather than acute thromboembolic events. Therefore, the absence of venous compressibility is the most reliable and significant finding when assessing for venous thromboembolism using Doppler ultrasound.