Transcatheter aortic valve implantation (TAVI) for isolated aortic regurgitation (AR) comprises <1.0% of all TAVI procedures performed in the USA. In this manuscript, we review the challenges, evidence and future directions of TAVI for isolated AR. There are no randomised clinical trials or mid-term data evaluating TAVI for isolated AR, and no commercially available devices are approved for this indication. Challenges in performing TAVI for isolated AR as opposed to aortic stenosis (AS) include: lack of a calcified anchoring zone for valve deployment, large and dynamic size of the aortic annulus and high stroke volume (during systole) and regurgitant volume (during diastole) across the aortic annulus during each cardiac cycle. Observational studies have shown that outcomes of TAVI for AR are worse than outcomes of TAVI for AS. However, newer generation TAVI devices may perform better than older generation devices in patients with AR. Two emerging valves (the JenaValve and the J-Valve) are designed with mechanisms to anchor in a non-calcified annulus, and these valves have shown promise for AR. Data on these devices are limited, and clinical investigation is ongoing. Randomised clinical trials are needed to establish TAVI as a safe and effective treatment for isolated AR.

中文翻译：

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对位：经导管主动脉瓣植入术治疗主动脉瓣关闭不全的挑战和局限性

用于孤立性主动脉瓣返流 (AR) 的经导管主动脉瓣植入术 (TAVI) 占美国所有 TAVI 手术的 <1.0%。在这份手稿中，我们回顾了 TAVI 用于孤立 AR 的挑战、证据和未来方向。没有评估 TAVI 治疗孤立性 AR 的随机临床试验或中期数据，也没有商用设备被批准用于该适应症。与主动脉瓣狭窄 (AS) 相比，对孤立性 AR 进行 TAVI 的挑战包括：缺乏用于瓣膜部署的钙化锚定区、主动脉瓣环的大且动态尺寸以及高每搏量（收缩期）和反流量（舒张期）在每个心动周期中穿过主动脉环。观察性研究表明，TAVI 治疗 AR 的结果比 TAVI 治疗 AS 的结果更差。然而，在 AR 患者中，新一代 TAVI 设备可能比老一代设备表现更好。两个新兴的瓣膜（JenaValve 和 J-Valve）设计有固定在非钙化瓣环中的机制，这些瓣膜已显示出对 AR 的前景。这些设备的数据有限，临床调查正在进行中。需要随机临床试验来确定 TAVI 作为孤立性 AR 的安全有效治疗方法。