Department of Cardiology, Houston Methodist DeBakey Heart & Vascular Center, Houston, Texas, USA; Department of Cardiology, Intermountain Medical Center, Intermountain Heart Institute, Salt Lake City, Utah, USA.
Department of Cardiology, Houston Methodist DeBakey Heart & Vascular Center, Houston, Texas, USA.
JACC Cardiovasc Imaging. 2021 Nov;14(11):2170-2182. doi: 10.1016/j.jcmg.2021.04.028. Epub 2021 Jul 14.
This study used cardiac magnetic resonance (CMR) to assess left ventricular (LV) remodeling in chronic aortic regurgitation (AR) to identify both forms of myocardial fibrosis and examine its association with clinical outcomes.
Chronic AR leads to LV remodeling, which is associated with 2 forms of myocardial fibrosis: regional replacement fibrosis that is directly imaged by late gadolinium enhancement (LGE) CMR; and diffuse interstitial fibrosis, which can be inferred by T1 mapping techniques.
Patients with chronic AR who were undergoing contrast CMR with T1 mapping for valve assessment from 2011 to 2018 were enrolled. Patients with a confounding etiology of myocardial fibrosis were excluded. In addition to quantification of AR severity and LV volumetrics, LGE and T1 mapping pre- and post-contrast were performed to measure extracellular volume (ECV) and indexed ECV (iECV). Patients were followed up longitudinally to assess for the composite event of death and the need for aortic valve replacement.
A total of 177 patients with isolated chronic AR were included (66% males, median age 58 years [IQR: 47.0-68.0 years]) with a median follow up of 2.5 years (IQR: 1.07-3.56 years). The iECV significantly increased with AR severity (P < 0.001), whereas ECV and replacement fibrosis did not (P = NS). On multivariate analysis, iECV remained associated with the composite event (P = 0.01). On Kaplan-Meier analysis stratified by AR regurgitant fraction (RF) and iECV, patients with AR RF severity ≥30% and iECV ≥24 mL/m demonstrated the highest event rate.
Among CMR biomarkers of fibrosis, iECV was more closely associated than replacement fibrosis or ECV with survival free of aortic valve replacement.
本研究采用心脏磁共振（CMR）评估慢性主动脉瓣反流（AR）患者的左心室（LV）重构，以确定心肌纤维化的两种形式，并研究其与临床结局的关系。
慢性 AR 导致 LV 重构，与 2 种心肌纤维化形式相关：由晚期钆增强（LGE）CMR 直接成像的区域性替代纤维化；以及可通过 T1 映射技术推断出的弥漫性间质纤维化。
纳入 2011 年至 2018 年因瓣膜评估而行对比增强 CMR 及 T1 映射的慢性 AR 患者。排除存在心肌纤维化混杂病因的患者。除了定量评估 AR 严重程度和 LV 容积外，还进行 LGE 和对比前后 T1 映射，以测量细胞外容积（ECV）和指数化 ECV（iECV）。对患者进行纵向随访，以评估死亡和主动脉瓣置换的复合终点事件。
共纳入 177 例孤立性慢性 AR 患者（66%为男性，中位年龄 58 岁[IQR：47.0-68.0 岁]），中位随访时间为 2.5 年（IQR：1.07-3.56 年）。iECV 与 AR 严重程度显著相关（P<0.001），而 ECV 和替代纤维化则无相关性（P=NS）。多变量分析显示，iECV 与复合终点仍相关（P=0.01）。Kaplan-Meier 分析按 AR 反流量（RF）和 iECV 分层，AR RF 严重程度≥30%和 iECV≥24mL/m 的患者事件发生率最高。
在纤维化的 CMR 生物标志物中，iECV 与生存无主动脉瓣置换的相关性比替代纤维化或 ECV 更密切。
