Understand What The AVNeo® Procedure Is
AVNeo® at a Glance
AVNeo™ (Aortic Valve Neo-cuspitization) is a safe surgery that has a movement close to a natural valve, with a cost benefit over other Aortic Valve replacement.
- AVNeo™ is implemented in over 20 countries by over 100 surgeons
- Creates a valve that allows natural movement of the aortic wall
- Uses the patients pericardium (tissue), leading to less allergic reactions and lower cost
- A relatively new procedure, with 12 years of outcome
- Is currently implemented in key hospitals around the globe and is gaining more and more attention daily
AVNeo™ (Aortic Valve Neo-Cuspidization) started in Japan from 2007. The treatment has been carried out worldwide with 3000+ cases. Favorable outcomes have been reported in conference presentations and articles (Ref. 1 and 2).
The initial cases are nearing 10 years (Ref. 2). Currently, more than 40 facilities in Japan, and more than 20 facilities globally have started AVNeo™ and the numbers are increasing.
General Aortic Valve Treatment at a Glance
Aortic valve disease has traditionally been treated surgically with a prosthetic valve. Prosthetic valves are costly, leading to a worldwide economic burden on healthcare. The durability of biological valves are also still under question. The largest effect on patients following mechanical valve operations is the need to take anticoagulant drugs for the rest of their lives, causing great strain on quality of life. The popularity of TAVR(TAVI) is also on the rise, but facility startup costs, post procedural complication management issues, continue to present resistance to its position as a “go to” treatment for aortic valve disease.
Features of AVNeo®
1. Use of Autologous Pericardium
- No immune resistance issues with autologous pericardium
- Stronger leaflet when using autologous pericardium
- Reasonable price
- Calcification is less likely to occur using autologous tissue.
Dialysis patients are prone to valve calcification. However, there is one report of no calcification in dialysis patients who underwent AVNeo™ (Ref.3). In an ex-vivo study, the strength of glutaraldehyde-treated autologous pericardium is reported to be about 4 times higher than other valves (Graph: Ref.4).
2. Natural movement of the aorta
AVNeo seeks to preserve the natural movement of the aorta. When the aorta contracts and expands during a cardiac cycle, the aortic leaflets also contract and expand in a dynamic movement.
The video below depicts the natural movement of the aorta.
- Following the AVNeo™ procedure, the annulus expands with the expansion of the aorta, ensuring a larger effective valve area. Postoperative low pressure gradients are maintained even in narrow annulus.
- When the valve closes, returning flow is absorbed in the entire aortic root, thus mechanical stress is on the leaflets is reduced.
There is no natural movement with prosthetic valve replacement surgery. Natural contraction and expansion of the aortic root is lost, because movement of the annulus is fixed. As a result, the effective valve area is reduced and postoperative pressure gradients are higher compared to cases where AVNeo™ were performed (Ref 5).
The following is an echo video of a normal aortic valve (left), an echo image of an aortic valve following AVNeo™ (right). (Spectrum tracking analysis of the annulus) There are no significant differences.
3. Valve design – Less likely to cause postoperative AR
In most cases, the height of commissures and the height of leaflet contact points in normal valves vary from patient to patient; even between patients with similar annular diameters.
- If the contact point of leaflet is low → free edge is longer (Blue line)
- If the contact point of leaflet is high → free edge is shorter (Orange line)
Since the leaflet’s contact points and the height of each commissure are on the same plane, “the distance of each commissure” and “distance of the free edge of the leaflet” corresponds 1:1. Therefore, free edge distance can be determined easily by measuring commissural distance.
On the other hand, the lengths of each leaflet and the proportions differ for each individual. The free edge of the leaflet should be carefully constructed adjusting the height when suturing in order to make the three leaflets the same height. Therefore, it is possible to achieve longer cooptation, and postoperative AR is less likely to occur.
References
- Aortic Valve Reconstruction Using Autologous Pericardium for Aortic Stenosis Circulation Journal Vol. 79 (2015) No. 7 p. 1504-1510
- Midterm outcomes after aortic valve neocuspidization with glutaraldehyde-treated autologous pericardium. 2018 Jun, Journal of Thoracic and Cardiovascular Surgery, 155(6):2379-2387
- Aortic valve reconstruction with autologous pericardium for dialysis patients. Interact Cardiovasc Thorac Surg. 2013 Jun;16(6):738-42
- Tensile strength of human pericardium treated with glutaraldehyde. Ann Thorac Cardiovasc Surg. 2012;18(5):434-7. Epub 2012 Apr 27.
- Immediate results of aortic valve reconstruction by using autologous pericardium (Ozaki procedure). Patologiya krovoobrashcheniya i kardiokhirurgiya = Circulation Pathology and Cardiac Surgery. 2016;20(2):44-48. (In Russ.).