Extremity vascular ultrasound

The role of ultrasound in the management of deep vein thrombosis (DVT)

Over the past thirty years, interventional radiology has dramatically changed the management of the vascular system. Today, diagnostics rely on three pillars of non-invasive imaging: duplex ultrasound scanning, multislice CT angiography, and MR angiography.

When deep vein thrombosis of the lower extremities is suspected, ultrasound addresses several tasks simultaneously:

• Assesses the patency of the venous bed.
• Helps select optimal access sites (typically via a patent popliteal or femoral vein).
• Serves as the main tool for postoperative monitoring in the outpatient setting.

It is important to note that treatment of isolated femoropopliteal DVT using interventional radiology methods is currently not performed, as it does not reduce the risk of developing post-thrombotic syndrome. However, when the iliac veins or inferior vena cava are involved, endovascular intervention is strictly indicated.

Intravascular ultrasound and treatment of iliofemoral DVT

When conventional external ultrasound is insufficient, intravascular ultrasound (IVUS) is employed. This method allows for visualization inside the vein to assess the lumen in detail after thrombus removal, as well as to monitor the proper expansion of the stent.

The endovascular treatment scheme is as follows:

1. Navigation and access: puncture is performed under ultrasound guidance, and the thrombus is crossed using a specialized hydrophilic guidewire.
2. Thrombolysis or thrombectomy: a catheter is placed for targeted thrombus dissolution (taking up to 72 hours) or pharmacomechanical thrombectomy is performed, allowing the vessel to be cleared in a single visit.
3. Stenting: large-caliber, self-expanding metallic stents are placed to keep the vessel open. Their precise positioning is verified specifically using IVUS.

Upper extremity venous ultrasound: common pathologies

Upper extremity venous obstruction is most commonly associated with two specific conditions requiring thorough ultrasound diagnostics:

• Paget-Schroetter syndrome: acute thrombosis of the subclavian or axillary vein caused by anatomical compression of the vessel by bony or muscular structures (thoracic outlet syndrome). Treatment begins with thrombolysis, followed by surgical resection of the first rib to decompress the space and subsequent angioplasty.
• Dialysis fistula pathologies: in patients undergoing hemodialysis, high venous pressure inevitably leads to stenoses and occlusions. Ultrasound monitoring allows for timely detection of narrowing. Endovascular treatment (angioplasty or stenting) is technically successful here, but unfortunately characterized by frequent recurrences.

Vascular intervention techniques

Once the ultrasound examination has identified the problem, the following percutaneous techniques are applied:

• Angioplasty (PTA): a balloon catheter is inserted into the vessel, advanced to the stenotic zone, and inflated. Balloons can be conventional or drug-eluting.
• Stenting: deployment of a metal framework. Stents are classified as balloon-expandable (expanding along with the balloon) and self-expanding (expanding due to their own elasticity upon sheath withdrawal). Covered stents isolate aneurysms or sources of bleeding.
• Embolization: artificial occlusion of a vessel (e.g., in bleeding or tumors) using coils, nitinol plugs, gelatin sponges (temporary effect), or polyvinyl alcohol particles (permanent effect).

Risks and complications

Endovascular procedures planned using diagnostic imaging are generally safe, but carry inherent risks:

• Minor complications: local hematomas, mild contrast reactions, nausea, transient fever, or dissection not requiring correction. Resolve spontaneously.
• Major complications (approx. 1% of cases): vessel rupture, pseudoaneurysm formation, distal embolization, stent migration, or severe allergic reactions to contrast media. Thrombolysis stands apart—it is associated with a high risk of bleeding (up to 30% of cases, predominantly at the puncture site).

Class and exam questions

What else to study on this topic

• Technique of percutaneous catheter-directed thrombolysis (CDT)
• Types of and indications for inferior vena cava filter placement
• Embolic agents: from gelatin sponges to drug-eluting microspheres
• Ultrasound findings and hemodynamics in superior vena cava syndrome (SVCS)

Other topics in the "Interventional radiology" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.