IVUS during haemodialysis access “aids device selection and adequacy of treatment”

Narayan Karunanithy outlines the benefits of intravascular ultrasound (IVUS) during haemodialysis access intervention.

Thoracic central veins include intra-thoracic segments of the internal jugular, subclavian, brachiocephalic veins and superior vena cava. These veins are located central to the superior thoracic aperture (C7–T1 intervertebral disc level), central to the lateral margin of the first rib and superior to the diaphragmatic caval opening.¹ Patients with haemodialysis access are prone to developing Thoracic Central Vein Obstruction (TCVO) due to their underlying renal failure, altered haemodynamics of the arteriovenous circuit and previous central vein catheter, pacemaker or defibrillator placement. The incidence of TCVO in this patient cohort is thought to be rising and currently estimated to be 20–40%.² TCVO may be partial (i.e. stenosis) or complete (i.e. occlusion).

Patients with TCVO can present with arm/neck/face/breast swelling, pain, access dysfunction and respiratory distress. Visible chest wall collaterals may also be unsightly for the patient.

Most of the haemodialysis circuit can be imaged readily with standard ultrasound, as the circuit is very superficial. However, TCVO can be virtually impossible to image with ultrasound. CT or MR venography can provide excellent depiction of central venous anatomy. However, CTV carries an additional radiation burden and MRV usually requires administration of gadolinium, which may be complex in this cohort of patients with end stage renal failure or approaching it. Hence the mainstay of CVS assessment currently is digital subtraction angiography (DSA).

IVUS is an invasive modality that provides cross-sectional imaging of the veins but without the need for ionizing radiation or contrast administration. In addition to being a diagnostic tool that is easy and repeatable, it aids treatment decision-making.

The VIDIO trial has demonstrated that DSA can underestimate the degree and morphology of iliofemoral vein stenosis when compared to IVUS. There is paucity of published literature evaluating IVUS for TCVO assessment in haemodialysis patients.³ de Graaf et al performed DSA and IVUS on 12 patients with suspected TCVO. IVUS showed significant stenosis in 12/12 versus 8/12 with DSA. After angioplasty, significant residual stenosis was demonstrated in 10/12 versus 3/12 with DSA. The authors concluded that IVUS was more sensitive in diagnosing significant TCVO and aided the decision-making process in deciding treatment strategy.⁴ This is in line with what we have learned from the iliofemoral venous treatment literature that IVUS aids precise device dimension selection (diameter and length of stenosis), appropriate landing zones and adequacy of treatment (for e.g. wall apposition of stent). These are fundamentally important steps that contribute to optimised outcomes.⁵ Clearly high quality large data studies are required to demonstrate the benefit of IVUS in haemodialysis access.

Currently no consensus exists on the optimum treatment of TCVO. The mainstay of treatment is high-pressure balloon angioplasty but the outcomes are generally poor with reported patency at six and 12 months 29–60% and 25% respectively. The use of bare metal stents has similarly poor outcomes with one-year patency 33–56%. The reported outcomes even with stent grafts are as low as 40% patency at 12 months. The patency rates with drug coated balloon angioplasty are better.⁶ Reliance on DSA alone to determine adequate treatment may have contributed to these relatively poor outcomes.

In conclusion, reliance on DSA alone for TCVO can under-estimate the extent and severity of these lesions. This can be overcome with use of IVUS. IVUS use during treatment aids appropriate device selection and adequacy of treatment.

References

1. Dolmatch BL, Gurley JC, Baskin KM et al. Central Vein Work Group and the Technology Assessment Committee. Society of Interventional Radiology Reporting Standards for Thoracic Central Vein Obstruction: J Vasc Access. 2019 Mar; 20(2): 114–122
2. McFall RG, Lu T. Application of Intravascular Ultrasound in End-Stage Renal Patients with Central Venous Occlusive Disease. Methodist Debakey Cardiovasc J. 2018 Jul-Sep; 14(3): 196–1993.
3. Gagne PJ, Tahara RW, Fastabend CP et al. Venography versus intravascular ultrasound for diagnosing and treating iliofemoral vein obstruction. J Vasc Surg Venous Lymphat Disord. 2017 Sep; 5(5): 678–6874.
4. de Graaf R, van Laanen J, Peppelenbosch N et al. The value of intravascular ultrasound in the treatment of central venous obstructions in hemodialysis patients. J Vasc Access. 2016 Mar;17 Suppl 1:S12–5
5. Murphy E. Use of IVUS to optimise outcomes in venous stenting. Venous News 6th April 2018
6. Kitrou PM, Papadimatos P, Spiliopoulos S et al. Paclitaxel-Coated Balloons for the Treatment of Symptomatic Central Venous Stenosis in Dialysis Access: Results from a Randomized Controlled Trial. J Vasc Interv Radiol. 2017 Jun;28(6):811–817.

Narayan Karunanithy is a consultant interventional radiologist at Guy’s and St Thomas’s Hospital (London, UK) and honorary senior lecturer at the School of Biomedical Engineering and Imaging Sciences at King’s College London (London, UK).