Transcatheter Aortic Valve Replacement for Pure Aortic Regurgitation

Corresponding Author

Aortic regurgitation (AR) is a valvular heart disease that displays geographical variability in prevalence, pathophysiology, and management strategies. AR is reportedly more prevalent in the Asian population. Data from the China-DVD (China Elderly Valve Disease) study revealed that AR was more common than aortic stenosis, with a prevalence of 16.5% vs 5.1%, respectively, and with a trend toward affecting younger patients.¹

In terms of its etiology, AR can occur in conjunction with aortic stenosis because of degenerative and calcified leaflets, but pure native aortic regurgitation (PNAR) presents a distinct anatomical profile and therapeutic challenges for transcatheter interventions. The causes of AR are diverse, ranging from degenerative changes, to functional annular dilatation, to bicuspid aortic valves and rheumatic diseases, with the latter still being encountered in transitional countries across the globe.

Anatomically, patients with AR frequently exhibit larger aortic dimensions and aortic annulus diameters, which pose technical challenges during transcatheter valve interventions. Most importantly, the absence of calcifications in the aortic annulus and valve leaflets, which is critical for anchoring in transcatheter aortic valve replacement (TAVR) procedures in aortic stenosis, further complicates interventions in PNAR.

Severe AR necessitates timely intervention caused by its deleterious effect on left ventricular (LV) function. Chronic volume overload causes progressive LV dilatation, increases wall stress, and ultimately causes systolic dysfunction. Current European and American guidelines recommend intervention for symptomatic severe AR and for asymptomatic patients with an LV ejection fraction below 50% or significant LV dilatation.^2,3 Surgical aortic valve replacement remains the gold standard.

For patients with high to prohibitive surgical risks, TAVR has emerged as an off-label alternative. However, outcomes for TAVR in PNAR have historically been suboptimal. Two anatomical challenges limit procedural success: the absence of annular calcification and a frequently enlarged aortic annulus in these patients. These factors undermine stable valve anchoring and increase the risks of device migration and embolization, which raise procedural mortality up to 25%.⁴ There is also a higher rate of complications, such as the need of valve-in-valve implantation and permanent pacemaker implantation.

In this issue of JACC: Asia, Yang et al⁵ presents a novel strategy to address these anatomical barriers: the noncoronary sinus pivot implantation (NCPI) technique. NCPI is a technical innovation that utilizes the noncoronary sinus as a pivot point for valve anchoring. In this approach, the valve is positioned at the base of the noncoronary sinus, while the stent frame is allowed to extend into the LV outflow tract at the contralateral cusps to provide a 3-point support for stable anchoring, thereby minimizing the risks of migration and embolization.

NCPI technique demands a thorough understanding of aortic root anatomy, precise fluoroscopic alignment, and meticulous catheter manipulation to achieve the ideal pivot point with the noncoronary sinus. Small variations in deployment angle, depth, or orientation may affect procedural success. The technique is associated with a relatively steep learning curve and a high level of operator expertise. Standardization and reproducibility remain key challenges, and these factors may limit broad adoption of the technique, particularly in centers or regions without extensive transcatheter experience.

That said, the results achieved from the study are encouraging, with device success rate improved from 70.7% from the cohort with conventional non-NCPI techniques, to 93.5% in the NCPI cohort (Table 1). There was a reduction in major adverse cardiac events from 51.1% to 19.5%. Notably, valve-in-valve procedures were reduced from 29.3% to 2.2%, and pacemaker implantation rates fell from 34.1% to 13%. Multivariate analysis identified both the use of NCPI and degree of aortic angulation as independent predictors of device success.

Table 1.

Features and Outcome of Different Technique and Device for Treating Pure Native Aortic Regurgitation

	Off-Label Use AS TAVR Device for Pure AR	Dedicated Device for Pure AR	Conventional Technique (Non-NCPI)	NCPI Technique
Device used	Evolut, Sapien, Navitor, and so on	JenaValve J Valve	Venus A VitaFlow	VitaFlow
Device success rate	73%-88%8,9	93%-95%8,9	70.7%5	93.5%5
>moderate residual AR	2%-10%8,9	1%-1.1%8,9	Not available	Not available
Risk requiring acute valve in valve procedure	11%9	1.1%9	29.3%5	2.2%5
Risk of device embolization	6%-15%8,9	1.1%-2%8,9	Not available	Not available
Rate of permanent pacemaker requirement	21%-22%8,9	15%-24%8,9	34.1%5	13%5

AR = aortic regurgitation; AS = aortic stenosis; NCPI = noncoronary sinus pivot implantation; TAVR = transcatheter aortic valve replacement.

The study underscores the anchoring advantage with the NCPI approach. Nonetheless, important limitations must be considered. The study is a single-center, nonrandomized trial with a short follow-up limited to 30 days, primarily evaluating short-term device and technical success. In addition, the success of NCPI depends on precise deployment and favorable anatomy, including aortic angulation of 30° to 60°, which may not be present in all patients. Thus, the anatomical suitability must be assessed case by case.

The landscape of transcatheter therapy for PNAR is rapidly evolving. Dedicated devices for PNAR have been developed to overcome the limitations of off-label TAVR use. These include the J-valve system (JC Medical Inc) and the JenaValve Trilogy (JenaValve Technology), both of which feature active fixation mechanisms that do not depend on annular calcification. The JenaValve Trilogy has demonstrated promising outcomes in the ALIGN-AR (Transcatheter aortic valve implantation in patients with high-risk symptomatic native aortic regurgitation) trial, with a technical success rate of 95%.⁶ The transfemoral J-valve system also reports a technical success rate of 93.7% and a lower pacemaker implantation rate of 9.5%.⁷

As these devices become more widely available and incorporated into practice, they may ultimately supplant off-label TAVR use in patients with PNAR, particularly in high-volume centers with access to these latest devices. Dedicated systems offer benefits of procedural consistency and reduced operator variability, making them more scalable solutions for broad adoption in transcatheter management of AR.

Nevertheless, the current study offers a valuable contribution to the field. In regions where PNAR is prevalent and access to dedicated AR devices remains limited, NCPI offers an innovative and effective solution to improve anchoring stability and, hence, treatment outcomes with existing TAVR platforms. It bridges the gap while waiting for popularization of dedicated devices for transcatheter treatment of PNAR.

Funding Support and Author Disclosures

Dr Chak-yu So is a physician proctor for Abbott, Boston Scientific, Edwards, and Medtronic; and serves as consultant for Jenscare and Venus Medtech. Dr Chan has reported that he has no relationships relevant to the contents of this paper to disclose.