The next spring forward in aortic stent grafting will be rooted in a greater understanding of the biomechanical forces acting upon devices alongside continued advances and specialization in imaging, according to some of the founding fathers of endovascular aneurysm repair (EVAR) who were gathered at CX on Wednesday morning in a session that marked more than four decades of EVAR development.
“When you think about aortic aneurysms, all of the devices are rigid, they are stiff, and the body changes with time,” said Christopher Zarins (Torrance, United States), a vascular surgeon involved in early development efforts at Stanford University. “For example, when you’re 6ft tall at the age of 20, you’re 5ft tall at the age of 80. You shorten, but the stent graft doesn’t… so we need to look at new materials and new devices that can reflect on the changing environment of the body itself.”
As imaging modalities progress, added Rodney White (Torrance, United States), also involved early on at Stanford, and “we can look more at diseases and the natural history—and the devices and how they need to change—I think we are all going to become imaging specialists, which is going to drive where these changes come from and show us how we have to progress.”
These visions of the future came as the assembled faculty reflected on the seminal moments of stent graft technology in the 1970s and into the early 1980s. Krassi Ivancev (Lund, Sweden) summarized the broad sweep of device development, including the revolutionary work of the late Nicolai Volodos in Soviet Ukraine and Juan Parodi (Buenos Aires, Argentina) between the Cleveland Clinic in the United States and in his homeland, which exhibited the simultaneous efforts taking place in the east and west as the pioneering journey proceeded. From the Gianturco stent in the earliest moments, through the advanced devices of today, the roots are clear, Ivancev said. “No question, Volodos was the first, but what started the revolution with stent grafting was Parodi, and that was reinforced by several teams working together worldwide.”
Echoing White, Ivancev also called on vascular specialists to “immerse yourself in imaging.”
Contributing thoughts via a prerecorded video, Parodi remembered how his work started in 1976, culminating in his first clinical case for an abdominal aortic aneurysm (AAA) in 1990. “That was a long journey, a lot of work, a lot of opposition,” he said, as he described performing the first AAA case in the world in the Argentinian capital with Julio Palmaz, who was behind the balloon-expandable stent.
Also in a video message, Frank Veith (New York, United States), involved in the first EVAR performed for a AAA Stateside, reflected how despite early resistance and scepticism, younger vascular specialists helped eventual widespread adoption. “We wanted to do everything that hadn’t been done before, so every one of our cases was a first,” he said. “This included ruptured aneurysms and things of that nature. We were treated as pariahs when we thought that we should be treated as messiahs.”
Fellow pioneer Michael Dake (Tucson, United States), an interventional radiologist who led the first placement of an aortic stent graft for a thoracic aneurysm in the United States at Stanford, pondered what could be ahead in the thoracoabdominal space as devices are approved and specialists try to understand which patients should be treated. “For me, the still unsolved issue is in dissection: we do not have a definitive way to treat dissection yet,” he added. “That is the challenge and goal we all have to focus on in the next few years because it is not going to be easy.”
Getting governmental agencies involved early will be another important lever to spur stent graft technology development going forward, added White. “The FDA [US Food and Drug Administration] sponsored many of us to have investigator IDEs [investigational device exemptions], where we could work with manufacturers, get their devices and then be able to progress that way too,” he said. “That kind of collaboration, particularly because we all have to get approval and government payment for these things … helps to move it along.”
