Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea.
Department of Radiology, Cardiovascular Imaging Center, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
JACC Cardiovasc Imaging. 2020 Dec;13(12):2561-2572. doi: 10.1016/j.jcmg.2020.07.007. Epub 2020 Aug 19.
The aim of this study was to investigate the relationship between extracellular volume fraction (ECV), a noninvasive parameter that quantifies the degree of diffuse myocardial fibrosis on cardiac magnetic resonance (CMR), and left ventricular diastolic dysfunction (LVDD) in patients with aortic stenosis (AS).
Myocardial fibrosis on invasive myocardial biopsy is associated with LVDD. However, there is a paucity of data on the association between noninvasively quantified diffuse myocardial fibrosis and the degree of LVDD and how these are related to symptoms and long-term prognosis in patients with AS.
Patients with moderate or severe AS (n = 191; mean age 68.4 years) and 30 control subjects without cardiovascular risk factors underwent CMR. LVDD grade was evaluated using echocardiography according to the 2016 American Society of Echocardiography/European Association of Cardiovascular Imaging guidelines. Clinical outcomes were defined as a composite of all-cause mortality or hospitalization for heart failure aggravation.
Patients in higher ECV quintiles had a significantly higher prevalence of LVDD. Higher ECV was particularly associated with decreased myocardial relaxation (septal e' <7 cm/s) and increased LV filling pressure (E/e' ratio ≥15). Although both impaired diastolic function and higher ECV were significantly associated with a worse degree of dyspnea, patients with higher ECV showed greater dyspnea within the same grade of LVDD. During a median follow-up period of 5.6 years, 37 clinical events occurred. Increased ECV, as well as lower septal e' and higher E/septal e' ratio, were independent predictors of clinical events, irrespective of age, AS severity, aortic valve replacement, and left ventricular (LV) ejection fraction. ECV provided incremental prognostic value on top of clinical factors and LV systolic and diastolic function.
Diffuse myocardial fibrosis, assessed using ECV on CMR, was associated with LVDD in patients with AS, but both ECV and LV diastolic function parameters provided a complementary explanation for dyspnea and clinical outcomes. Concomitant assessment of both LVDD and diffuse myocardial fibrosis may further identify patients with AS with greater symptoms and worse prognosis.
本研究旨在探讨细胞外容积分数（ECV）与主动脉瓣狭窄（AS）患者左心室舒张功能障碍（LVDD）之间的关系。ECV 是一种无创参数，可定量评估心肌弥漫性纤维化的程度。
心肌活检显示的心肌纤维化与 LVDD 相关。然而，关于非侵入性量化弥漫性心肌纤维化与 LVDD 程度之间的关联以及这些因素与 AS 患者的症状和长期预后的关系的数据较少。
191 例中重度 AS 患者（平均年龄 68.4 岁）和 30 例无心血管危险因素的对照者接受心脏磁共振（CMR）检查。根据 2016 年美国超声心动图学会/欧洲心血管成像协会指南，采用超声心动图评估 LVDD 分级。临床结局定义为全因死亡率或因心力衰竭加重而住院的复合终点。
ECV 五分位较高的患者 LVDD 的发生率显著较高。较高的 ECV 与心肌舒张功能减退（室间隔 e'＜7cm/s）和 LV 充盈压升高（E/e'比值≥15）尤其相关。尽管舒张功能障碍和 ECV 升高均与呼吸困难程度恶化显著相关，但 ECV 较高的患者在同一 LVDD 分级中呼吸困难更严重。在中位随访 5.6 年期间，37 例患者发生临床事件。在校正年龄、AS 严重程度、主动脉瓣置换和左心室射血分数后，ECV 升高以及室间隔 e'降低和 E/室间隔 e'比值升高均为临床事件的独立预测因素。ECV 提供了独立于临床因素和 LV 收缩及舒张功能之外的额外预后价值。
CMR 上的 ECV 评估显示，弥漫性心肌纤维化与 AS 患者的 LVDD 相关，但 ECV 和 LV 舒张功能参数均为呼吸困难和临床结局提供了补充解释。同时评估 LVDD 和弥漫性心肌纤维化可能进一步识别出症状更严重、预后更差的 AS 患者。
