Do we need to rethink treatment of aortic valve pathologies in younger patients?

Currently, a wide range of treatment modalities exists for aortic valve pathologies. The options range from surgical and interventional replacement of the aortic valve with tissue (biological) devices, surgical replacement with mechanical devices and complex aortic valve repair strategies to preserve the native aortic valve in selected cases. While interventional and surgical valve replacement with biological devices is deemed to be the treatment of choice in elderly patients (>70 years), the preferred treatment modality in younger patients (<60 years) is still under discussion. For proper decision-making, the physician has to balance the specific risks of implantation, the long-term durability of the devices and the quality of life which may be affected by permanent anticoagulation or the need for pacemaker implantation. Hence, in younger patients below the age of 60 years, an “ideal” replacement device should meet the following criteria: low risk of implantation, extended long-term durability, optimal haemodynamics, low risk for permanent pacemaker implantation and no need for anticoagulation. In 1995, Duran et al. (1) described the concept of de-novo aortic valve reconstruction using autologous pericardium. Chan et al. (2) reported a similar technique in 2011. In the same year, Ozaki et al. (3) described a standardized technique for this procedure (Ozaki procedure, Aortic Valve Neocuspidization—AVNeo). In addition, Ozaki developed corresponding leaflet sizers and cutting templates, which are commercially available and may facilitate the procedure, thus making it more reproducible. Although early experience with AVNeo has shown promising results, long-term durability data are still lacking. In 2018, Ozaki et al. reported on their experience in a series of 850 patients undergoing AVNeo. The mean follow was 4.5 years with some patients reaching up to 10 years (4). The authors showed a cumulative incidence for reoperation of 4.2%. However, this and other studies suggested that the mode of degeneration between a commercially available tissue prosthesis and AVNeo using autologous pericardium may be substantially different. While the main indication for reoperation in biological prostheses seems to be a stenotic valve, the vast majority of re-operations after AVNeo was due to valve insufficiency or endocarditis. During the last years, an increasing number of cardiac surgeons from the US, Europe, Africa and Asia has been learning the AVNeo procedure as an alternative option, especially for younger patients. The growing acceptance of the AVNeo procedure has led to more and more published results from different centers. In the current issue of this journal, Benedetto et al. (5) report their results from two centers in the UK, together with a Meta-Analysis on more than 1200 AVNeo cases from different centers in Japan and across Europe. The UK experience comprises 55 patients undergoing AVNeo following the surgical technique described by Ozaki et al. The authors showed a freedom from the composite end-point (death, structural valve degeneration (SVD), reoperation and endocarditis) of 92.5% over a period of 24 months. Furthermore, they achieved low transvalvular gradients which are in accordance with other published data (6). They conclude from their experience that AVNeo is an effective treatment of aortic valve stenosis and insufficiency, bicuspid and tricuspid valve configurations and endocarditis. Besides these encouraging early results, AVNeo has been reported to exhibit a very low risk for permanent pacemaker implantation (6), which may be an important consideration in younger patients. The authors also performed a meta-analysis on clinical outcome parameters (SVD, endocarditis and reintervention) after Aortic Valve Neocuspidization and compared those with results after implantation of various biological valve substitutes. They calculated an incidence rate of 0.34%, 0.45% and 1.07% per patient-year for SVD, endocarditis and reintervention following AVNeo. Since the majority of cases included in their meta-analysis were from the Ozaki publication (850 cases), Benedetto and colleagues performed a second analysis without these cases and found similar rates of 0.24%, 0.58% and 0.14%/patient-year for SVD, endocarditis and reoperation. This adds further strength to the fact that AVNeo for trileaflet aortic valve reconstruction using autologous pericardium as a standardized procedure can be widely adopted by cardiac surgeons after initial, albeit extensive training. Furthermore, within their meta-analysis, the comparison of seven different valve substitutes including AVNeo showed no significant difference regarding SVD, endocarditis and reintervention except for the EDWARDS Magna Ease prosthesis. The Magna Ease showed a lower incidence of reintervention per patient-year. Altogether, the reported results by Benedetto and colleagues, together with the increasing body of evidence for AVNeo (7–10) allow the preliminary conclusion that this procedure offers an alternative treatment modality for patients suffering from all aortic valve pathologies. For final judgement on the value of AVNeo, more data on long-term durability are an indispensable requirement. Besides reporting single center experience, future focus should lie on the initiation of multicentre, prospective, randomized-controlled-trials to assess long-term clinical outcomes after Aortic Valve Neocuspidalization versus prosthetic valve replacement.