Author + information
- †Division of Cardiology, Emory University Hospitals, Atlanta, Georgia
- ‡Division of Cardiology, Charles Nicolle Hospital, Rouen, France
- ↵∗Reprint requests and correspondence:
Dr. Vasilis Babaliaros, Structural Heart and Valve Center, Emory University Hospital, Suite F606, 1364 Clifton Road, Atlanta, Georgia 30322.
The early animal experiments of transcatheter aortic valve replacement (TAVR) were performed by implanting the valve in the Hufnagel position (descending aorta just distal to the left subclavian artery) after the creation of aortic insufficiency (AI) created by a bioptome (1). The absence of calcium in the aortic annulus of sheep, low coronary arteries, and lack of valve sizing knowledge precluded successful TAVR in the orthotopic position. Using the Hufnagel position, mid-term evaluation of transcatheter valves in the systemic circulation was studied. In contrast to the animal studies, TAVR in humans with aortic stenosis was very successful, with appropriate anchoring and sealing in aortic annuli that were significantly less distensible and calcified.
Since then, multiple other TAVR devices have been tested in animals and received CE mark approval for treatment of aortic stenosis. Of note, both the JenaValve (JenaValve Technology, Munich, Germany) and Symetis ACURATE TA (Symetis, Ecublens, Switzerland) were approved in Europe in 2011. These 2 valves share several characteristics. They are deployed transapically (primarily); they are self-seating; they are anatomically oriented into the commissures; and they can be deployed in animal models in the orthotopic position. In fact, the lack of calcium allows these devices to work more effectively. Because of their lower radial force compared with other TAVR devices and nontransfemoral delivery systems (up until recently), both devices have not had a market share in Europe. However, their design may be ideal to treat AI.
The 2 most common transcatheter valves available (Edwards Lifesciences, Irvine, California, and Medtronic, Minneapolis, Minnesota) have been used to treat native aortic valve insufficiency. Though neither valve was designed to treat this condition, successful cases have been reported but required significant oversizing (>20% to 30%) and/or the need for a second valve (2). These procedures have been performed at our centers on a compassionate basis.
In this issue of JACC: Cardiovascular Interventions, single-center experience with the Symetis valve and multicenter experience with the JenaValve for the treatment of AI are reported. Wendt et al. (3) describe an initial experience with the Symetis valve with 100% procedural success and no AI in any patient except 1 with mild AI at 3 to 6 months follow-up (n = 8). Additionally, there were no deaths or strokes in these patients. Seiffert et al. (4) initially reported on 5 patients with similar results, and now report on expanded use in multiple centers with the JenaValve (5). In this larger series of 31 patients, 1 procedure was unsuccessful, requiring a valve-in-valve procedure; mortality at 30 days was 12.9%, and mortality at 6 months was 19.3%. One patient had a progressively worse paravalvular leak that was thought to be secondary to valve calcification, and another developed endocarditis at 6 months. Stroke did not occur.
The good news from these reports is that in selected patients, acute procedural success for both devices is very high, and live case demonstrations performed recently have validated this to the TAVR community. The JenaValve received CE mark approval for the treatment of AI in 2013, and we suspect that Symetis will receive the same approval in the near future. The not so good news is that TAVR for AI appears to be a niche market, with only 10% of valve patients having AI (6), and high-risk/inoperable patients that would undergo TAVR for AI are even fewer. What we don’t know is whether these devices will be durable or feasible in patients with progressive annulus-root dilation. With a mortality of almost 20% at 6 months in the JenaValve series, we do not have any insight into the question. Additionally, do patients with a history of AI secondary to endocarditis have a prohibitively high risk of recurrent endocarditis after TAVR? This question is also unanswered and will require significantly more than 39 combined patients from the 2 papers to address.
In the future, devices that are specifically designed for the treatment of AI may occupy this space. These devices may be focused on stabilization of the annulus-root complex and may be able to treat many different variations of AI. One such system that has had success in early human feasibility trials is the Helio transcatheter aortic dock (Edwards Lifesciences). The Helio device is a stent frame dipped in polyethylene terephthalate fabric that captures the aortic leaflets at the aortic root (7). A SAPIEN XT (Edwards Lifesciences) can then be deployed within the Helio dock to sandwich the native aortic leaflets in between, sealing and perhaps stabilizing the annulus. The treatment of AI in patients with an aneurysmal aorta or aortic dissection deserves very specialized device development that not only can stabilize the aortic pathology at the annulus-root level, but also facilitate treatment of the diseased ascending and transverse aorta (TAVR with TEVAR [thoracic endovascular aortic repair] or TAVR-TEVAR). For now, however, everything old becomes new again, as we use 2 approved TAVR devices to treat the new indication of AI.
↵∗ Editorials published in JACC: Cardiovascular Interventions reflect the views of the authors and do not necessarily represent the views of JACC: Cardiovascular Interventions or the American College of Cardiology.
Dr. Babaliaros is an investigator for Edwards Lifesciences; and is a consultant for Bard Medical, DirectFlow Medical, and Intervalve. Dr. Cribier is a consultant for Edwards Lifesciences.
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