August 17, 2022

Expert Consensus Outlines Appropriate Use Guidance for IVUS in Lower Extremity Arterial and Venous Interventions

August 17, 2022—In a recent JACC: Cardiovascular Interventions publication, Secemsky et al outline expert consensus recommendations for use of intravascular ultrasound (IVUS) during lower extremity arterial and venous interventions. IVUS is increasingly utilized during lower extremity revascularization, and this consensus helps define the clinical scenarios in which this modality might be valuable until additional data are available.

KEY FINDINGS

For iliac artery revascularization, recommendations for IVUS included:
- Preprocedural: Appropriate for evaluation of ambiguous lesion severity, vessel sizing, and minimizing contract and may be appropriate for evaluation of vessel occlusion etiology, plaque morphology, and filling defects
- Intraprocedural: Appropriate for determining location of crossing tracks and next therapeutic step and may be appropriate for vessel sizing for device placement
- Postprocedural: Appropriate for optimizing the intervention, including dissection and residual stenosis, and may be appropriate for determining the need for stent post dilation
For femoropopliteal artery revascularization, recommendations for IVUS included:
- Preprocedural: Appropriate for evaluating lesion severity, filling defects, vessel sizing, and minimizing contrast and may be appropriate for determining vessel occlusion etiology and evaluating plaque morphology
- Intraprocedural: Appropriate in all clinical scenarios
- Postprocedural: Appropriate in all clinical scenarios
For tibial interventions, IVUS was deemed appropriate for use during all procedural stages in all clinical scenarios.
For iliofemoral venous interventions, IVUS was considered appropriate for use during all procedural stages in all clinical scenarios.

Secemsky and colleagues sought to delineate appropriate use of IVUS during various phases of lower extremity interventions using an expert consensus survey developed by a 12-member multidisciplinary physician group. The writing group created clinical scenarios of common decision points and categorized them by stage of intervention (preintervention, intraprocedure, postprocedure).

A total of 12 clinical scenarios were created to evaluate the role of IVUS in arterial intervention, and eight were developed for iliofemoral venous intervention. Subsequently, the writing group drafted five clinical vignettes for each scenario, resulting in 180 clinical vignettes for the arterial survey and 40 clinical vignettes for the venous survey. Two vignettes were chosen at random for each scenario for the arterial survey to limit its length.

The writing group nominated 15 voting experts for each survey, who were asked to grade the appropriateness of each scenario on a scale of 1 to 9. Responses were summarized as median values as “appropriate for specific indication” (score, 7-9), “may be appropriate for specific indication” (score, 4-6), and “rarely appropriate for indication” (score, 1-3). Two rounds of voting took place.

For iliac artery revascularization, in the preprocedural stage, IVUS was deemed appropriate for the evaluation of ambiguous lesion severity, vessel sizing, and minimizing contrast and may be appropriate to evaluate vessel occlusion etiology, plaque morphology, and filling defects. Intraprocedurally, IVUS was considered appropriate for determining location of crossing tracks and the next therapeutic step and may be appropriate for vessel sizing for device placement. In the postprocedural stage, IVUS was appropriate for optimizing the intervention, including identifying dissections and residual stenosis, and may be appropriate to determine the need for stent postdilation.

For femoropopliteal artery revascularization, in the preprocedural stage, IVUS was recommended as appropriate for evaluating lesion severity, filling defects, vessel sizing, and minimizing contrast and may be appropriate to determine vessel occlusion etiology and evaluate plaque morphology. In the intraprocedural and postprocedural stages, IVUS was deemed appropriate for use across all clinical scenarios.

For tibial artery interventions, IVUS was recommended as appropriate for all stages and clinical scenarios.

IVUS was considered appropriate for use for iliofemoral venous interventions during all procedural phases and in all clinical scenarios.

Development of this consensus document was funded in part by unrestricted educational grants from Boston Scientific Corporation and Philips IGT, but the companies had no role in participation or access to survey results.

Although peripheral use of IVUS was strongly supported across most arterial and venous clinical scenarios, future studies on the long-term rates of major adverse limb events and cost-effectiveness are needed, noted the investigators.

ENDOVASCULAR TODAY ASKS…

Lead investigator Eric Secemsky, MD, with Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, Massachusetts, elaborates on the group’s findings and how the consensus derived can help guide clinical practice.

One of the assumptions described in the publication is that IVUS may increase procedure time. Similarly, skill in IVUS can vary considerably. What opportunities for training exist to help reduce the learning curve and increase efficiency in use?

Great question. The setup and delivery of IVUS catheters is relatively intuitive and once the lab or OR are set up, it often takes no more than 5 minutes. I typically time our cases to prove this point. In addition, once I deliver the catheter, I am actively interpreting the images and determining my next steps. I think if anything, I have become more efficient with greater use of IVUS as I can make more data-driven decisions on the device sizing and plan the next steps for the procedure. However, this definitely takes some time to develop and perfect. As such, we have several initiatives we are planning to execute to address these issues. First, we are planning a prospective multicenter study to evaluate the efficiency of IVUS-guided procedures to help debunk some of the concerns about excess procedure time. Second, both Philips IGTD and Boston Scientific, as well as other vendors, have robust support teams for helping set up imaging labs and improve comfort with the devices. For instance, Philips now has integrated IVUS through their Azurion imaging systems, which makes utilization seamless. Lastly, we have to now focus on opportunities to create education and training content for new and emerging operators. Outside of reimbursement, I feel that one of the most critical barriers to use is just with image interpretation and knowing how to act on what is seen. As such, there are multiple society and industry efforts to provide online or app-based imaging resources, and get live training at conferences and other in-person events. It is a rather quick learning curve and I think with these efforts, we will see comfort and adoption increase rapidly.

What other real-world barriers to routine IVUS use are there, and what are the possible solutions?

I think what remains a limitation is reimbursement. This goes for most peripheral devices. With the continuous looming threats of reimbursement cuts, in particular for the ASC/OBL setting, it makes it challenging to help promote what many of us feel is optimal practice. We have to be understanding of the financial constraints associated with these devices. Unfortunately, the reimbursement issue has resulted with repurposing of IVUS catheters, which I think is unfortunate for patient care. I hope that through both emerging data, greater use, and cost-effectiveness studies that payers see the value of IVUS imaging and are willing to support its reimbursement.

Where do you see opportunities for improvements in next-generation intravascular imaging?

The current IVUS devices are quite good, but there is always room to iterate. I’d love to see peripheral co-registration with IVUS, as one thing we lack is identifying length of disease and location without this capability. I think with co-registration, we will not only see more efficient procedures, but also will use less contrast and hopefully perform more optimal revascularization. In addition, OCT is an important tool in the coronary and should have more of a role in the periphery. There are emerging devices that include both IVUS and OCT imaging. Although a primary limitation as of now in the periphery for OCT is the need for contrast and the ability to opacify larger vessels, I think technology will be refined to allow for greater peripheral use.

What are the next steps in the exploration of IVUS utility? Additional applications in a similar study? Alternate trial designs in similar procedures?

As mentioned, we have many plans for future work. One ongoing study in conjunction with Philips IGTD is to track IVUS utilization and outcomes among different vascular beds using real-world data. Our plan is to follow how IVUS adoption increases with time, identify where we see growth or lack of growth, and explore other areas of emerging interest in IVUS use. We are continuing to examine procedural cost-effectiveness with IVUS utilization and track patient outcomes. I think we will also see some targeted studies to address specific areas of the procedure IVUS can be helpful, such as how to determine how to best treat arterial dissections using IVUS-based criteria.

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