SIR Today 2021| March 26, 2021
On Thursday, March 25, experts discussed the status of evolving venous disease therapies during “Venous Thromboembolism and Deep Venous Disease: The State of Evidence and Its Impact on Treatment Strategies.” The session included five lectures, beginning with Akhilesh K. Sista, MD, FSIR, who presented “Submassive Pulmonary Embolism Intervention: Confidence With the Current Level of Evidence?”
“The last 7 years have been very busy for submassive pulmonary embolism (PE) research,” said Dr. Sista. In his presentation, Dr. Sista reviewed the recent literature and studies that have been done to determine whether catheter-directed treatment (CDT) is effective for treating PE. While some data are promising, he said that researchers haven’t been able to conclusively answer this question because of insufficient outcomes data, so large-scale randomized trials are needed. “A rigorous, randomized trial of CDT would achieve much more than its primary objective,” Dr. Sista said. Much like the ATTRACT Trial did, such a study could identify risk factors and offer biological insights that could drive research. Such a trial is coming in the near future, Dr. Sista said, pointing to his PE-TRACT Trial now in the works. “Hopefully we’ll have some positive news next year,” he said.
This call for deeper researcher was echoed by Suresh Vedantham, MD, FSIR, in “Post-Thrombotic Syndrome: The Need for More Evidence to Improve Outcomes.” Dr. Vedantham reflected on the findings of the ATTRACT Trial, which studied the efficacy of CDT to prevent post-thrombotic syndrome (PTS). Though the study did not prove its efficacy, ATTRACT sparked other questions and set the stage for the C-TRACT trial, which is still enrolling.
“There is the possibility here to improve patient care,” Dr. Vedantham said, “but it’s going to require a lot more research on our part.”
The rigorous review of data continued during “Are We Entering a Post-IVC Filter World? Current Evidence and Utilization,” presented by Robert K. Ryu, MD, FSIR. “There is no evidence to support that the prevalence of VTE is going down. If anything, it’s increasing,” said Dr. Ryu. “But IVC filter placement has taken a sharp downward trend.” Dr. Ryu identified several factors for this decline, such as safety concerns regarding retrieval devices and FDA recommendations that they be removed. Dr. Ryu reviewed recent literature on IVC use and risks and ultimately concluded that, although they are being used less, the filters are still relevant—and there are new technologies on the horizon that could limit the risk substantially.
“I think they still have potential,” said Dr. Ryu. “We have a lot of work to be done, though, and I do think we should rethink how we use them and if there is a safer way.” Dr. Ryu also said that studies are needed to see how these filters react in underrepresented patient demographics.
In “VTE Challenges: Evidence for Management of Complex Cases,” Fionnuala Ni Áinle, PhD, MB, joined from Ireland to review data and guidelines for handling VTE in difficult cases, such as pregnancy. “VTE is a leading cause of maternal death in the United Kingdom,” Dr. Áinle said, which has led to rigorous research on how to manage and identify PE in pregnant individuals. The primary clinical concern has been determining how to identify or rule out PE without having to expose the patient to radiation. Dr. Áinle presented research that created a guideline to help determine how to rule out the need for imaging, which has since been included in the 2019 European guidelines for handling embolism in pregnant patients. She also discussed how to determine the optimal duration of anticoagulation for VTE and reviewed the guidelines for the management of VTE in cancer patients. In all situations, particularly pregnancy and cancer, Dr. Áinle recommended a multidisciplinary approach.
In “The Future of Deep Venous Intervention: Lessons Learned from Venous Biomechanical Modeling,” presented by Ramsey Al-Hakim, MD, attendees received a crash-course in venous stent mechanics, physics and function. According to Dr. Al-Hakim, the ideal venous stent has high radial force and high crush resistance—but this model may be flawed.
“We know a lot about arteries, but there’s a lack of understanding about veins,” he said, pointing to a common misconception that veins are elastic, when, he said, they’re actually more rigid than arteries. This lack of knowledge on arteries, paired with the established model for stent construction, has led to longstanding complications with stent placement such as adjacent vein narrowing, which can slow venous flow.
Dr. Al-Hakim showed attendees a model of a proposed stent that could solve the problem of adjacent vein narrowing. The Auxetic stent is a research prototype (not approved by the FDA) that varies from typical stent construction in that it applies longitudinal force that elongates as it deploys. “It’s the same gain with less metal,” Dr. Al-Hakim said, and told attendees that the unique shape would prevent vein narrowing.
While further research is conducted to determine the efficacy of the Auxetic stent, however, IRs can still work to combat vein narrowing. “With strong radial stents, we have to be careful with sizing,” Dr. Al-Hakim said. “If you oversize, you can compromise inflow and introduce complications.”
Registrants can view the session on demand via the Digital Video Library.
Watch for this article to be published on the morning of Friday, March 26.