New developments in retrievable inferior vena cava filters reviewed
Monday, 03 Sep 2012 10:49
The new Crux inferior vena cava filter can be implanted and retrieved safely and shows a low rate of pulmonary embolism, Anthony J Comerota, director, Jobst Vascular Institute, adjunct professor of Surgery, University of Michigan, USA, told delegates at the Vascular Annual Meeting (7–9 June 2012). He spoke about new developments with inferior vena cava filters at the conference in National Harbor, USA.
Comerota noted that the second randomised trial with inferior vena cava filters was performed by investigators from the Maimonides Medical Center, Brooklyn, New York. In the trial (Usoh et al. J Vasc Surg 2010), 156 patients were randomised to the Greenfield (Boston Scientific) or TrapEase (Cordis) filters.The study was stopped at the interim analysis stage because, at 12 months, the symptomatic vena cava occlusion rate was 7% in the TrapEase group vs. 0% in the Greenfield group (p=0.019). “Therefore, the IRB [institutional review board] thought it was unethical to continue the trial,” Comerota said. “This study showed that double conical filters are associated with unacceptable high rates of venal cava occlusion.”Comerota also commented on the results of the Systematic Review of the Use of Retrievable Inferior Vena Cava Filters, by Angel et al (J Vasc Interven Radiol 2011).
“This is the most robust look at retrievable inferior vena cava filters. It included a Medline search for 37 studies comprising 6,834 patients. It did not include randomised trials but there were 11 studies thought to be of high suitability. What they found in data from 6,834 filters was that 58% were used without any underlying pulmonary embolism or deep venous thrombosis, the traditional prophylactic use; 70% were inserted via the femoral vein, but interestingly there were no reports of placement complications. The mean follow-up was less than 10 months, which is a shortcome,” Comerota said.
He added that the rate of pulmonary embolism in the high suitability studies was 2%; deep vein thrombosis was reported in 5.4% of the cases and the rate of vena cava thrombosis was 2.8%. Migration and filter fracture occurred predominantly in the G2 filter (Bard).
“Retrieval occurred in only 34% of these retrievable inferior vena cava filters, with a mean time of 72 days. But when attempts were made within three months, retrieval success was over 90%. When retrieval was attempted at 12 months the success rate dropped dramatically to 37%. Overall, the retrieval failure rate was 5.5%. ‘Lost to follow-up’ was the most common reason for non-retrieval,” he said. “The conclusion was that ‘in high-risk patients for whom anticoagulation is not feasible, retrievable inferior vena cava filters seem effective in preventing pulmonary embolism, but that long-term complications are a serious concern’.
“So is there a problem with not removing a retrievable inferior vena cava filter? The FDA believes there is. To date, there have been over 1,000 reported device adverse events, and the FDA strongly states that with retrievable inferior vena cava filters, we need to consider removing the filter as soon as protection from pulmonary embolism is no longer needed,” he said. “This systematic review shows that retrievable filters are effective in the short term, but there are serious concerns with long-term complications.”
After that, Comerota discussed the results of what he considers to be “the most important study published in a number of years on pulmonary embolism and inferior vena cava filters”. The study by Stein et al (Am J Med 2012; 125:478-484) aimed to determine categories of patients with pulmonary embolism in whom vena cava filters reduce in-hospital case-fatality rate. Using the Nationwide Inpatient Sample (1999–2008), the investigators analysed more than 2 million patients.
“They found that there was a significant reduction in mortality in patients with pulmonary embolism who received an inferior vena cava filter. Independently of whether they were stable and not receiving lytics, stable and receiving lytics, unstable and receiving lytics or unstable patients, they all had a reduction in mortality. The only subgroup that did not fare well with the filter comprised stable patients with pulmonary embolism with an associated deep vein thrombosis group (6.7% with filter vs. 5.3% with no filter, p<0.0001). To me this is counter-intuitive but the number was 721,200 so it is a robust denominator,” Comerota said.
“In general, we can see that those stable patients who received lytic therapy or unstable patients may well benefit in a reduction in mortality by receiving an inferior vena cava filter. The number needed to treat is 11 or less, which is a very high return on your investment. So the conclusion was that it does seem to be prudent to consider inferior vena cava filters in pulmonary embolism patients who are going to have thrombolytic therapy or who are unstable.
Comerota concluded the talk analysing the results of the Crux filter from Crux Biomedical.“I think the Crux device, with a brand new design, is the most innovative development in inferior vena cava filters. The clinical trial has just been completed, and the data have been submitted to the FDA. The device has a helical design, with a nitinol wire frame, and the filtering is due to extruded polytetrafluoroethylene (ePTFE),” he described.
One hundred and twenty five patients (58% male, mean age 59 years) were enrolled in the multicentre, single-arm study and followed up for 180 days. The indications for filter placement were surgical risk for pulmonary embolism in 36% of the cases and contraindication to anticoagulation in 37%.
Technical success with the device was 98%. Deployment time was five minutes and retrieval time was seven minutes. Retrieval success was 98% at a mean of 84 days. “Retrieval and placement can be obtained both from the jugular and the femoral approach,” Comerota said.
Fifty seven per cent of the patients had the filter remaining in place as permanent. Pulmonary embolism was observed in 2.4%. He added, “However, there was no filter migration, embolisation, fracture or tilting.” He concluded that the device “can be implanted and retrieved safely with a very high success rate and a low rate of pulmonary embolism.”
Leading interventionalists hail new certificate at CIRSE 2012
Wednesday, 19 Sep 2012 16:12
Key members of the Society of Interventional Radiology (SIR) have praised a new dual certificate for diagnostic radiology and interventional radiology, saying it recognises interventional radiology as a “a new form of medicine”.
Past SIR presidents Brian Stainken, (Interventional Radiology, Roger Williams, Medical Center, Providence, USA) and John Kaufman, (Dotter Interventional Institute, Portland, USA) and current SIR president Marshall Hicks, (MD Anderson Cancer Center, Houston, Texas), spoke to Interventional News at CIRSE (Cardiovascular and Interventional Radiology Society of Europe; 15–19 September 2012, Lisbon, Portugal) about why the decision of the American Board of Medical Specialties (ABMS) to recognise a new dual certificate in diagnostic radiology and interventional radiology was so important. The new certificate means that interventional radiology will be a primary specialty, alongside diagnostic radiology, rather than a sub-specialty of diagnostic radiology. Furthermore, it identifies interventional radiologists as being more than just technicians—it establishes them as clinicians who are able to care for patients.Kaufman, who chaired the joint SIR and American Board of Radiology (ABR) task force that developed the joint certificate, explained that a prior application for a single certificate in interventional radiology was rejected by the ABMS in 2009. After the failure of this application, he explained, the decision was made to apply for a dual certificate in a diagnostic radiology and interventional radiology because they “did not want to inadvertently downplay the importance of imaging.” Kaufman added that, with the new certificate, interventional radiology education would be able to “keep up” with the changing developments in interventional radiology and commented: “It [the new certificate] will open up opportunities for interventional radiology fellowships in cancer, women’s health, peripheral artery disease, musculoskeletal and paediatrics.”
Stainken, who is also editor-in-chief of Interventional News, said that the new certificate was “recognition and acknowledgement” that interventional radiology was a new form of medicine. He added that he believed the certificate represented a “monumental point” for interventional radiologists–and not just those practising in America but for interventional radiologists worldwide. He explained: “It is recognition that interventional radiology is a clinical skill set and it is an important skill set.”
According to Marshall Hicks, the new certificate is a “continued evolution” of the discipline of interventional radiology and said it was recognition of how the discipline had evolved and become “an integral part of medicine.” He added that it should be emphasised that the ABR played a “critical role” in getting the new certificate approved. He said: “This [certificate] would not have happened if they had not taken the lead. We [SIR] needed them to represent radiology at the ABMS. They had to be behind this and be supportive and enthusiastic.” He added that, in particular, Gary Becker (executive director of the ABR), deserved credit for ensuring the new certificate was approved.
In a press statement, Becker said: “Since the early 20th century, board certification—a form of professional self-regulation—has assured the public of the qualifications of medical professionals. Only rarely does the house of medicine acknowledge the importance of a new primary specialty certificate in fulfilling these responsibilities. ABR supported the creation of this primary certificate based on the need to ensure that future trainees acquire the requisite combination of clinical, procedural and interpretive skills necessary for the safe and competent practice of interventional radiology. The interventional radiology and diagnostic radiology certificate ensures that board-certified interventional radiologists are trained and qualified to deliver the highest level of care available today, and it demands that this same quality be made available to all future patients.”
Interventional radiology in the USA now a primary specialty in medicine
Thursday, 13 Sep 2012 17:25
L to R: Marshall E Hicks, John A Kaufman, Gary J Becker, Jeanne M Laberge and Matthew A Mauro
On 11 September, the American Board of Medical Specialties (ABMS) recognised the unique interventional radiology skill set with the new dual certificate in interventional radiology and diagnostic radiology. The Society of Interventional Radiology (SIR) has hailed the affirmation of the specialty’s role in patient care.
The SIR hailed the decision by the ABMS—the organisation that has oversight of the 24 recognised medical specialty boards—to approve the American Board of Radiology’s (ABR’s) application for a new Dual Primary Certificate in Interventional Radiology and Diagnostic Radiology. With this approval, the ABMS and its member boards confirmed the benefit to patients of the unique interventional radiology skill set comprised of competency in diagnostic imaging, image-guided procedures and periprocedural patient care.The new Dual Certificate in Interventional Radiology and Diagnostic Radiology will be the fourth primary certificate for the ABR and the 37th overall in the United States. A primary certificate is different from a subspecialty certificate as it designates a unique and distinct area of medicine, rather than an area of focus within an existing specialty.
“Support for the Dual Certificate in Interventional Radiology and Diagnostic Radiology by the ABMS is a seminal event in the history of interventional radiology—and one that will benefit future patients by providing well-trained minimally invasive image-guided specialists,” said SIR President Marshall E Hicks, who represents the national society of nearly 5,000 doctors, scientists and allied health professionals dedicated to improving health care through minimally invasive treatments. “The Society of Interventional Radiology applauds ABR for its dedication and hard work in advancing the specialty and the interventional radiology skill set, a unique combination of interpretive and procedural skill, accompanied by corresponding clinical expertise,” said Hicks, the head of the division of diagnostic imaging at the University of Texas MD Anderson Cancer Center, Houston, USA.
“This is an important step in the formalisation of the interventionalist’s clinical role. Recognition of the interventional radiologist’s imaging, technical and periprocedural patient care competencies speaks directly to the specialty’s focus on patients, innovation and advanced image-guided techniques,” said John A Kaufman, a past president of SIR and director of the Dotter Interventional Institute in Portland, USA. “First and foremost, future patients will benefit from this,” said Kaufman, who chaired the SIR/ABR task force that has been developing the certificate since 2005.
“Since the early 20th century, board certification—a form of professional self-regulation—has assured the public of the qualifications of medical professionals,” said Gary J Becker, ABR executive director. “Only rarely does the house of medicine acknowledge the importance of a new primary specialty certificate in fulfilling these responsibilities. The ABR supported the creation of this primary certificate based on the need to ensure that future trainees acquire the requisite combination of clinical, procedural and interpretive skills necessary for the safe and competent practice of interventional radiology. The interventional radiology and diagnostic radiology certificate ensures that board-certified interventional radiologists are trained and qualified to deliver the highest level of care available today, and it demands that this same quality be made available to all future patients,” he added.
“ABR is pleased to offer this new certification and notes its importance to patients, the public and the profession. The addition of the interventional radiology/diagnostic radiology certificate to the other primary certificates offered by the ABR—Diagnostic Radiology, Radiation Oncology and Medical Physics—rounds out a full range of ABR primary certification services in diagnostic, therapeutic and image-guided procedures, as well as periprocedural clinical care,” said ABR President James P Borgstede. “I would like to acknowledge the vision, leadership and commitment to quality patient care of ABR past presidents N Reed Dunnick, and Bruce G Haffty, who helped to guide the application and approval process. Finally, the ABR notes that a very positive and productive collaboration with SIR on this important endeavour made the new certificate possible,” he added.
“The interventional radiology and diagnostic radiology certificate will help ensure that all patients in the country continue to receive high-quality, consistent, diagnostic, procedural and clinical interventional care,” said Jeanne M LaBerge, an ABR trustee and interventional radiologist at the University of California, San Francisco, USA. “The recent approval of the interventional radiology and diagnostic radiology certificate formalises this belief and gives ‘specialty’ status to the field of interventional radiology while maintaining its intimate and necessary relation to diagnostic radiology,” said Matthew A Mauro, an SIR past president and ABR trustee. “The elevation of interventional radiology to a ‘specialty’ level with its own distinct residency programme places interventional radiology/diagnostic radiology on the same level as surgery, paediatrics and internal medicine in the ABMS hierarchy. This ABMS vote is much more than a superficial clerical action—it is one that initiates a formalised enhanced training programme that will benefit patients across the country and serve as a model throughout the world,” added Mauro, professor and chair, department of radiology, University of North Carolina, Chapel Hill, USA.
“Securing the interventional radiology and diagnostic radiology certificate took tremendous effort by many individuals and support from many societies,” said Kaufman.