3.2 Aortic Frontiers: Will Branched Arch and Thoraco-abdominal Devices Outperform Surgery?

These proceedings summarize the educational activity of the 16th Biennial Meeting of the International Andreas Gruentzig Society held January 31-February 3, 2022 in Punta Cana, Dominican Republic

Faculty Disclosures     Vendor Acknowledgments

2022 IAGS Summary Document

Statement of the problem or issue

The first endovascular aortic stent-graft was implanted by Nikolay Volodos in Khrakov, Ukraine, on May 4, 1984.¹ However, this achievement did not receive much attention outside of Eastern Europe. It was not until 1990, when the first abdominal aortic endoprosthesis was implanted by Juan Parodi and Julio Palmaz in Buenos Aires, Argentina, and 1992 when endoprostheses were implanted into the thoracic aorta by Michael Dake and into the abdominal aorta by Frank Veith in the USA, that transluminal endovascular interventions began to receive significant attention.^2-4 Standard endovascular aortic repair (EVAR) for abdominal aortic aneuryms (AAA), and thoracic endovascular aortic repair (TEVAR) for thoracic aortic aneurysms (TAA), have largely replaced open surgical repair, with lower rates of mortality, morbidity, and paraplegia. In addition, procedural times and in-hospital stays are shorter. Yet despite these gains, aneurysms of the aortic arch and thoracoabdominal aneurysms remain a challenge. With open surgery approaches, high rates of strokes and paraplegias are continuing problems in the management of these complex aortic aneurysm repairs. Also, the technique of chimney graft repair, requiring brachial access and manipulation of the arch, can have high stroke rates. Newer endovascular devices with branches and fenestrations have been developed to try to circumvent these problems.

Gaps in knowledge

A major issue is the unavailability of many new devices with fenestrations (FEVAR) and branches (BEVAR) in several countries, including the USA. Whereas some of the aortic endoprostheses are off-the-shelf devices that have received CE-marking and regulatory approval, others have to be produced as custom-made devices (CMDs) without such approval possible. Hence, the interventionalist carries the responsibility for proper device use, as stated in the accompanying letters of the manufacturing companies. Despite these limitations, such CMDs are used in Australia and Europe, with liability covered by institutions and insurance carriers.

One major consequence of this lack of availability of either approved off-the-shelf or CMD aortic endoprostheses is the difficulty in both planning such procedures using special computer programs as well as the often very demanding implantation into challenging anatomies. Another consequence of having few devices, less device-specific training, and reduced skills is that open surgery may also be needed more frequently as a result. Also, in the absence of having complex CMD endoprostheses, there are risks to “pushing the limits” using standard devices, particularly regarding instructions for use (IFU) for suitable landing zones, irregular aneurysm necks, and neck angles. These may not appear as problems immediately following the implantation of EVARs and TEVARs, but over time and with progression of disease, patients may require subsequent even more demanding procedures with proximal and distal extensions.

Possible solutions and future directions

In Europe and Australia, thoraco-abdominal FEVAR and BEVAR by now have become routine, and long-term data are favorable. Experience with FEVAR and BEVAR in the aortic arch is rapidly increasing, yet these are still lacking large series and long-term data. All these complex procedures work best in dedicated aorta centers. Besides lack of expertise, there also is a large selection of necessary additional materials, supplies, and equipment that may not be readily available in smaller centers whenever procedural challenges occur.

CMDs often require long production times and often have to be shipped around the world, which may take up to 2-3 months. With very large aneurysms at high risk of rupture, and in symptomatic patients and emergencies with actual ruptures, more rapid solutions are needed. A larger variety of approved off-the-shelf devices would help. Also, physician-modified devices in the hands of experienced interventionalists familiar with planning tools have become a more frequent alternative to CMDs, and not only because they are rapidly available, but also may be cost saving. Liability, of course, is with the physician, who also requires extra knowledge and training. Lower-profile devices are needed for branched and fenestrated endoprostheses, since narrow and calcified access arteries may be problematic in complex procedures, especially in women. Lower-profile devices in combination with large-bore closure systems will facilitate percutaneous approaches while avoiding surgical cut-downs. These improvements in closure devices are still desired. Technical innovations such as fusion imaging for the cannulation of target arteries, which reduces both procedure times and radiation exposure, are very helpful. The development of robotic techniques could further decrease radiation doses.

References

1. Criado FJ. Nicholay Volodos and the origins of endovascular grafts. J Endovasc Ther. 2012;19(4):568-569. doi:10.1583/12-3972L.1

2. Parodi JC, Palmaz JC, Barone HD. Transfemoral intraluminal graft implantation for abdominal aortic aneurysms. Ann Vasc Surg. 1991;5(6):491-499. doi:10.1007/BF02015271

3. Mitchell RS, Dake MD, Sembra CP, et al. Endovascular stent-graft repair of thoracic aortic aneurysms. J Thorac Cardiovasc Surg. 1996;111(5):1054-1062. doi:10.1016/s0022-5223(96)70382-3

4. Marin ML, Veith FJ, Cynamon J, et al. Initial experience with transluminally placed endovascular grafts for the treatment of complex vascular lesions. Ann Surg. 1995;222(4):449-465; discussion 465-469. doi:10.1097/00000658-199522240-00004