Intravascular Ultrasound (IVUS)

The purpose is anatomical precision inside the vessel at the moment decisions are being made: whether a narrowing is truly significant, what size stent the vein needs, and whether a deployed stent is fully open and well apposed. Because it is invasive, IVUS is reserved for cases where this information is likely to change the treatment.

• Patients undergoing venography or endovascular treatment for deep venous obstruction or May-Thurner anatomy
• Iliocaval stenting, before and after deployment
• Selected arterial interventions where angiography alone may underestimate disease

IVUS is an adjunct to a procedure already planned on clinical grounds, not a standalone screening test.

How IVUS works

The catheter is passed through a sheath and gently advanced along the vessel. Cross-sectional images show the true vessel diameter, plaque, clot, compression and the relationship between a stent and the vessel wall. Because IVUS does not rely on contrast filling alone, it can reveal disease that venography underestimates.

When IVUS is used

• Iliocaval venous obstruction: assessing May-Thurner anatomy, post-thrombotic scarring and obstruction of the iliac veins or vena cava, and defining where healthy vessel begins and ends.
• Venous stent planning: accurate diameter measurements guide stent size and length, and IVUS confirms expansion, wall contact and coverage after deployment.
• Arterial procedures: in selected interventions, IVUS characterises plaque, confirms vessel size and assesses the result of angioplasty or stenting.

Preparation is the same as for the associated angiogram or intervention: review of medications, kidney function and bleeding risk, plus the usual fasting instructions for sedation. No additional preparation is required for the IVUS component itself. As always, bring an accurate list of blood thinners and allergies.

During the catheter procedure, usually under local anaesthetic with sedation, the IVUS probe is advanced through the vessel and records cross-sectional images of the wall, lumen and surrounding structures. Measurements guide balloon and stent selection, and the probe is withdrawn once the information has been gathered. The catheter is removed at the end of the examination.

No recovery period is needed for the imaging itself; recovery is determined by the access site and any treatment performed at the same sitting. Anticoagulant or antiplatelet medication and follow-up imaging relate to the underlying intervention, and results are reviewed with you alongside the angiographic findings.

IVUS itself emits no ionising radiation and adds little risk beyond the catheter procedure it accompanies. Relevant points:

• The risks are mainly those of vascular access and the associated intervention: bleeding, vessel injury, clotting and infection
• Fluoroscopy (X-ray guidance) is still used to position the catheter
• IVUS is invasive, so it is reserved for cases where its measurements will alter management
• Like all imaging, its findings are interpreted with the clinical picture, not in isolation

IVUS provides high-resolution internal measurements and can reduce uncertainty in complex anatomy.

IVUS is generally used when conventional venography or angiography does not provide enough detail about the inside of a vessel. It is most established in complex venous intervention, where it can reveal the true severity and length of iliac or caval obstruction and guide accurate stent sizing and placement.

Alternative imaging includes duplex ultrasound, CT or MR venography and catheter venography. IVUS is usually performed when treatment is already being considered rather than as a routine diagnostic test. The decision should reflect whether the additional information is likely to change management.

Patients should understand that IVUS guides the procedure but does not by itself determine whether a stent is necessary. Symptoms, prior thrombosis and other imaging remain essential because venous compression can occur without clinically important disease. The consultation should also cover contrast use, anticoagulation, access-site care and the surveillance required after any stent is placed.

Yarra Vascular Surgeons uses IVUS selectively during complex endovascular procedures to define obstruction, measure vessels and guide stent placement, as part of a broader clinical and imaging assessment.

IVUS can reveal venous and arterial disease that conventional imaging underestimates and improves the precision of complex endovascular treatment. Contact our rooms to discuss referral for deep venous or complex arterial assessment.