British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom.
Division of Cardiovascular Diseases, Department of Medicine, UPMC Heart & Vascular Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
JACC Cardiovasc Imaging. 2019 Feb;12(2):283-296. doi: 10.1016/j.jcmg.2018.11.026.
Aortic stenosis is characterized both by progressive valve narrowing and the left ventricular remodeling response that ensues. The only effective treatment is aortic valve replacement, which is usually recommended in patients with severe stenosis and evidence of left ventricular decompensation. At present, left ventricular decompensation is most frequently identified by the development of typical symptoms or a marked reduction in left ventricular ejection fraction <50%. However, there is growing interest in using the assessment of myocardial fibrosis as an earlier and more objective marker of left ventricular decompensation, particularly in asymptomatic patients, where guidelines currently rely on nonrandomized data and expert consensus. Myocardial fibrosis has major functional consequences, is the key pathological process driving left ventricular decompensation, and can be divided into 2 categories. Replacement fibrosis is irreversible and identified using late gadolinium enhancement on cardiac magnetic resonance, while diffuse fibrosis occurs earlier, is potentially reversible, and can be quantified with cardiac magnetic resonance T mapping techniques. There is a substantial body of observational data in this field, but there is now a need for randomized clinical trials of myocardial imaging in aortic stenosis to optimize patient management. This review will discuss the role that myocardial fibrosis plays in aortic stenosis, how it can be imaged, and how these approaches might be used to track myocardial health and improve the timing of aortic valve replacement.
主动脉瓣狭窄的特征是进行性瓣膜狭窄和随之而来的左心室重构反应。唯一有效的治疗方法是主动脉瓣置换术，通常建议在严重狭窄和左心室失代偿证据的患者中进行。目前，左心室失代偿最常通过典型症状的发展或左心室射血分数显著降低至<50%来识别。然而，人们越来越感兴趣的是使用心肌纤维化评估作为左心室失代偿的更早和更客观的标志物，特别是在无症状患者中，目前指南依赖于非随机数据和专家共识。心肌纤维化具有重大的功能后果，是导致左心室失代偿的关键病理过程，可分为 2 类。替代纤维化是不可逆的，可通过心脏磁共振上的晚期钆增强来识别，而弥漫性纤维化发生得更早，具有潜在的可逆性，可使用心脏磁共振 T 映射技术进行量化。该领域有大量的观察性数据，但现在需要在主动脉瓣狭窄的心肌成像中进行随机临床试验，以优化患者管理。这篇综述将讨论心肌纤维化在主动脉瓣狭窄中的作用，如何对其进行成像，以及这些方法如何用于跟踪心肌健康并改善主动脉瓣置换的时机。
