Large-scale IVUS analysis adds “meaningful data” to growing pool of evidence

Eric Secemsky
A large-scale analysis of the use of Philips’ intravascular ultrasound (IVUS) in lower extremity peripheral vascular interventions adds “meaningful data” to a growing pool of evidence advocating the continued use of the imaging methodology, Eric A Secemsky (Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, USA) tells Vascular News. The focus now, he believes, should be on understanding and addressing barriers to widespread adoption of the technology. What are the key takeaways from this study? In our analysis—which I presented for the first time at Transcatheter Cardiovascular Therapeutics (TCT) 2021 (4–6 November, Orlando, USA)—IVUS use made up about 11% of lower extremity arterial interventions, and when used as part of those procedures, was associated with improved outcomes, including decreased risks of amputation and thrombosis. So, although causality is hard to prove in an observational study, that association seems robust when IVUS was used during the peripheral vascular procedures. Another take-home message is that IVUS use during iliofemoral venous stenting was actually quite high—it was used in over 50% of procedures. I think what this shows is that if you are not using IVUS, you are going to be in the minority when you are performing iliofemoral venous stenting. We have to restrain causal interpretation here, but when IVUS was used as part of a venous procedure, there were fewer hospitalisations for stent embolisation or stent thrombosis, and so we have to assume that IVUS played at least a partial role in those outcomes. What are the benefits and drawbacks of real-world data? The strengths of real-world data are that they represent the patients we take care of in clinical practice and the large sample size allows us to look at important subgroups while still analysing a meaningful number of procedures. They also allow us to collect important information on use patterns—so, in this case, how IVUS is being used over time and how it is being used by different providers. There are limitations as well, and we conduct observational analyses like this one with caution in terms of causal inference. You can gain a good understanding of what outcomes look like between patients who are treated with IVUS versus those not treated with IVUS, but there are certainly important characteristics that we are not able to capture in a claims-based analysis such as anatomical considerations and the reasons why IVUS was used. With this analysis, we have been able to provide some real-world evidence that IVUS appears to be associated with a beneficial outcome as part of a procedure, and, overall, I think that these are meaningful data to help guide us forward in terms of the continued use of IVUS. However, we must be mindful of some of the limitations associated with real-world data. This has proven to be a popular story on the Vascular News website—do you have any views on why that might be? We have increasingly been performing endovascular procedures in the peripheral vascular space, yet our patients are still having adverse events such as venous stent embolisation. I think we understand that we can do something better here, and I think everyone in the field is looking to see how we can improve our outcomes. We have learned a lot from the coronary space where IVUS has been an important adjunctive therapy to improve outcomes, and so I think with that type of experience behind us, as well as some (albeit limited) data out there to support IVUS use in peripheral interventions, and then also our anecdotal experience, more and more people are understanding the value of what IVUS adds to optimise the procedure and achieve better outcomes for our patients. How does your data compare to previous studies of IVUS in the peripheral space? We have performed a pretty exhaustive systematic review summarising all the data on IVUS that hopefully will be in press in the near future. There are actually limited data in the arterial sphere, and most are from either from single-centre or small, multicentre, retrospective studies. That being said, the data that are available have primarily shown that IVUS can be beneficial in multiple phases during peripheral arterial intervention. On the venous sides, there are stronger data thanks to the VIDIO study, which was a prospective study evaluating the benefits of IVUS during peripheral venous intervention. Those data are probably the highest-level data we have in the peripheral IVUS space. Overall, I think that all the data out there, including from this latest analysis, are showing consistent findings of benefit. You announced a new global consensus for the appropriate use of IVUS at Vascular Interventional Advances (VIVA) 2021 (5 – 7 October, Las Vegas, USA)—do these new real-world data inform the recommendations at all? The consensus document really helps harmonise where experts in the field feel IVUS is beneficial during peripheral interventions. I think it also demonstrates that there is a lot of support for incorporating IVUS routinely into practice and that this is not dependent on the need for more prospective data. These sentiments are already set without the availability of a large-scale randomised trial—ongoing, resulting, or otherwise. I think the take-home message from the global consensus document is that IVUS is an important adjunct to peripheral procedures and this mirrors the growth in IVUS use we observed in the Medicare studies. What is next for IVUS in peripheral vascular interventions? Our focus now is on trying to understand other barriers to adoption outside of generating more prospective data. I think that with the results of the consensus document, there is a clear and strong endorsement for using IVUS during peripheral interventions and now we need to understand why people are not using it. One of the reasons will be reimbursement, and that is hard to control, but a lot of it relates to educating practitioners to readily interpret IVUS images and understanding how to build the technology into their workflow without creating delays or extending the length of the procedure. Do you think it is time for guidelines to advocate the use of IVUS in peripheral interventions, or is there still a way to go in terms of having enough data to back that up? Based on the consensus of operators and the already increasing use of IVUS—especially in the iliofemoral venous system—I think it should be given a high level of recommendation in any upcoming guidelines. Obviously, there are economic considerations, but from a safety standpoint there is really no harm with these devices. IVUS is meant to improve outcomes, which we and others have shown, and so I think that it definitely deserves inclusion in the guidelines with high support.
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