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2 decades of AAA repair
Editor’s Note:Cardiology Today is celebrating its 20th anniversary in 2017. We are reaching out to experts in cardiology for their take on changes in CV medicine since the publication launched in 1997. For this article, Michael L. Marin, MD, Julius H. Jacobson II, M.D. Professor of Vascular Surgery and chairman of the department of surgery at Icahn School of Medicine at Mount Sinai, and surgeon-in-chief of the Mount Sinai Health System, focuses on advances in endovascular repair of abdominal aortic aneurysms.
Twenty years ago, the majority of patients who had abdominal aortic aneurysms and thoracic aortic aneurysms had open operations. That was the standard of treatment. We would directly expose the aorta by an incision in the chest or abdomen. After it was exposed, we would place a replacement artery where the aneurysm was located. This was a major operation requiring a fair amount of blood transfusions, significant intraoperative time, hospitalizations ranging between 7 and 14 days and a recovery time of 6 to 12 months.
In the past 20 years, we have begun to embrace and understand how minimally invasive surgery for the treatment of AAA can be an effective and functional way of treating this disease in the long term.
The story of the most important advance began in 1992 with the publication of the treatment of AAA using a stent graft device by Juan C. Parodi, MD, PhD, who was chief of the department of cardiovascular surgery at the Instituto Cardiovascular de Buenos Aires. Parodi was the first in the world to repair an AAA using a stent graft device. In November 1992, Parodi came to the U.S. and helped me and our team at Montefiore Medical Center perform the first case in the U.S.
That ushered in a whole new period of investigation to define the proper technique, procedure and technology that would allow us to more easily and safely perform minimally invasive AAA repair and to create a long-term durable solution.
In the very early period, I used to build these devices myself. We had an investigator-sponsored investigational device exemption from the FDA, which allowed me to serve as a producer of the endoprosthesis. Obviously, the quality of the technology with the homemade devices was never up to the level of what we have today. In the past 20 to 25 years, the technology has improved dramatically, with the understanding of the forces and the requirements of the device. For instance, the homemade devices that I would build in 1992 did not have the durability, strength or long-term functionality of a commonly used modern device such as the Gore Excluder AAA Endoprosthesis (W. L. Gore & Associates).
In the late 1990s, the first commercial devices were approved by the FDA. The first commercial device to reach the market was the EVT Endovascular AAA Graft (EndoVascular Technologies). The AneuRx device, made by AneuRx Inc., a venture capital-financed company eventually acquired by Medtronic, and the first generation of the Gore Excluder AAA Endoprosthesis followed soon after.
The success of those first commercial devices brought dramatic improvements in the device design so that they would not disintegrate over time and would facilitate the procedure itself. While the devices I built were balloon-expandable, many of the early commercial devices were self-expanding with complex delivery systems. The priority was not just on building a functional graft that was useful, but also on building a mechanism by which it would be delivered into the arteries.
As technology improvements have occurred, we are now able to treat a larger proportion of the market of patients with AAA. This includes patients whose aneurysm is very close to the renal artery. More recently, devices have been developed that can seat themselves and seal appropriately in a shorter neck for long-term durability.
We have now begun to develop devices with side branches and fenestrations, allowing us to bridge the segment of the aorta with branches in it, which was not possible before.
Disclosure: Marin reports he serves as a consultant for W. L. Gore & Associates and formerly served as a consultant for Cordis and Medtronic.