NEW STUDY DEMONSTRATES IVC FILTERS ‘SAFE AND EFFECTIVE’ IN TREATING VENOUS THROMBOEMBOLISM

continued from page 1 multicenter, prospective, open-label, non-randomized trial that studied the safety and efficacy of IVC filters from six manufacturers. It was a joint effort of the Society of Interventional Radiology (SIR) and the Society for Vascular Surgery (SVS). The study was conducted at 54 sites in the U.S. between Oct. 10, 2015, and March 31, 2019. During that time, filters were implanted in 1,421 patients, of whom 1,019 patients had an existing deep vein thrombosis (DVT) or PE.

Researchers found that IVC filters were effective in helping to prevent PEs in patients experiencing a DVT where anticoagulation medicines failed or were not an option for the patient. Approximately half of the patients in the study had their filters removed within three months of placement without complication or recurrence.

“The question should not be only ‘should we place a filter?’ but ‘how should we offer comprehensive filter-inclusive care of patients with venous blood clots, comprised of a detailed patient evaluation, a plan for retrieval after placement, and frequent follow-up with evaluation for filter removal or replacement,’” said Matthew S. Johnson, MD, an interventional radiologist and professor of radiology and surgery at Indiana University School of Medicine in Indianapolis, and coprincipal investigator on PRESERVE. “PRESERVE showed what questions we should ask as clinicians: ‘Does this person continue to require protection against PE, and, in light of changing clinical status and available therapies, is the current filter needed?’ And then make an informed decision on how to continue care.”

Vascular surgeon David Gillespie, MD, spoke on PRESERVE at the VEITHsymposium 2022. “DVTs and PEs are a significant cause of death worldwide, and understanding fully how tools like IVC filters can be used to prevent the progression of a DVT into a PE allows physicians to safely treat patients at risk of death from venous thromboembolism [VTE],” said

Gillespie, of Beth Israel Deaconess Medical Center in Brockton, Massachusetts, and co-principal investigator on PRESERVE. “Now that the study is complete, we have a roadmap for better filter utilization. We need to solidify a clearer set of practice guidelines for venous thromboembolic disease, based on its symptoms, location and complications. Further studies will focus on how the different manifestations of venous thromboembolic disease may benefit from filter-inclusive care.” Gillespie said that “approximately 10 years ago or so, the clinical management of patients with VTE and the prophylaxis of potential VTE in trauma patients was not well studied with regard to the use of IVC filters.” The result of the PRESERVE trial has been that “essentially, these filters are safe and effective for therapeutic [and prophylactic] use in the patient population [in question],” he continued, and this despite the “challenges” of the COVID-19 pandemic, the “high dropout rate,” and the fact that “a large number of patients” had their filters removed.

To date, PRESERVE is the largest prospective study investigating the real-world patient outcomes of IVC filter use. “Congratulations to Dr. Gillespie, Dr. Johnson, and their many colleagues for shepherding this large collaborative multispecialty, multicenter clinical trial to completion,” said SVS President Michael C. Dalsing, MD. “This highly impactful study provides the realworld evidence needed when recommending IVC filter placement to protect our patients from a potentially lethal disease and when to remove that filter after it has accomplished the desired effect.” from page 1 sentation with rupture in 95 patients, the research team found—with 75% presenting before and 66% after Medicare established ultrasound screening criteria. “Overall, only 16% AAAs were detected on screening, 23% after 2007, with no significant change per year,” they report. “Patients with incidentally detected AAAs were older, had larger AAAs, more likely female, and to present with rupture, but had similar incidence of progression to and type of repair.”

Overall surviv al in AAA patients was 94%, 72% and 34% at one, five and 15 years—“significantly lower than age and sex-matched controls throughout the study,” Sen et al established.

“Traditionally, it has been believed that based upon single-center series, VQI registry studies, hospital-based data, that outcomes in women are poorer than in men,” says Kalra in an interview with Vascular Specialist ahead of SCVS 2023. “Traditionally, aneurysms have been picked up much less frequently in women than in men. We also know that the actual incidence is lower per 100,000 [patient years], which is what we have confirmed yet again with this population-based study.”

Sen points to the finding around the disparity involving female diagnosis and repair as breaking new ground in this area of AAA. “All the rest of the findings are supportive data for a lot of trends we already see, but nobody has ever actually put it down on paper that aneurysms are diagnosed and repaired in women almost a decade later than men with similar age-adjusted mortality,” she says. “What additionally came to light from this study was that, even though the screening guidelines came in over a decade ago, incidental detection is still the commonest [avenue].”

They now have a new baseline to address these issues, Sen continues. She points to newly initiated research in the UK set to look into AAAs in women. The multinational collaboration of researchers received endorsement from the Global Cardiovascular Research Funders Forum (GCRFF)

Multinational Clinical Trials Initiative for the WARRIORS (Women’s abdominal aortic aneurysm research: repair immediately or routine surveillance) trial. It aims to answer the question: Should women have their aneurysms repaired electively using endovascular aneurysm repair (EVAR) at smaller diameters than men to improve their survival and quality of life? Imperial College London in London, England, is co-ordinating the study, but it will include collaboration with vascular surgeons from Canada, Denmark, The Netherlands, and Sweden, as well as the U.S.

The investigators behind WARRIORS have noted that the rationale and need for this trial, which seeks to recruit nearly 1,200 women, stems from the poor outcomes suffered by women with AAAs. Although women contribute 15–20% of total AAA burden, and one-third of ruptures, they have been significantly underrepresented in trials which guide current AAA repair, the WARRIORS investigators detailed, adding that women have smaller arteries, a four-fold higher rupture risk, and lose eligibility for EVAR at smaller AAA diameters.

“We have learnt that women worry a lot about their AAA, and modeling has suggested that repair of AAA at 4cm for women might re sult in improved quality of life and reduced overall cost,” the WAR RIORS investigators recently commented.

“These potential benefits as well as reduction in aneurysm-related mortality, would need to be balanced against the operative risk of early repair.” They state that these areas of uncertainty, regarding the optimal strategy for AAA repair in women, are what the trial seeks to answer.

The Mayo epidemiological study provides timely data pointing to the fact that these and similar questions regarding aneurysms in women are relevant, Sen adds. The need for a population-based study to highlight these was great, Sen and Kalra relate.

“We don’t have good natural history data, or epidemiology, of aortic aneurysms in the U.S.,” remarks Sen. “Everything that we use, we take from studies performed in Europe and Australia.

Among the few studies performed in the U.S., one of them was from this same Rochester epidemiology data—which was in the 1980s. Since the 80s, the two major changes that have happened are the introduction of endovascular repair, which has become the commonest way of repairing these AAAs, and the introduction of a screening protocol for men.”

The questions that the research team were looking to answer were: Do advances in screening really work? How comprehensive is the adoption of the program, and who is being screened? “Are we identifying more aneurysms in women as a side effect?” adds Sen. “A lot has changed in clinical practice, and the outcomes of this are being reported using large hospital-based treatment datasets.” The impact of these developments and changes at a population level was not known, Kalra chimes in, nodding toward the questions around potential benefits of early detection of these aneurysms in women, “although data exists that screening for them has been shown not to be cost-effective.” She says the chief finding was actually something of a surprise. “It’s not that women do poorly with AAA repair, it’s because they are nearly a decade older by the time you are fixing them,” adds Kalra.

As they concentrate their efforts on this particular area of the dataset, Sen says future efforts and analysis will be aimed at getting to the bottom of factors that lead to later diagnosis and repair of aneurysms in women.