Department of Cardiology, Boston Children's Hospital, and the Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
Department of Radiology, Brigham and Women's Hospital, and the Department of Radiology, Harvard Medical School, Boston, Massachusetts.
J Am Coll Cardiol. 2014 May 6;63(17):1778-85. doi: 10.1016/j.jacc.2013.11.066. Epub 2014 Mar 13.
This study sought to analyze cardiac magnetic resonance (CMR) measurements of myocardial extracellular volume fraction (ECV) and late gadolinium enhancement (LGE) in children and young adults with congenital aortic stenosis (AS) to determine the extent of fibrosis and examine their association with aortic valve and ventricular function.
Patients with congenital AS frequently have impaired diastolic ventricular function and exercise capacity that may be related to myocardial fibrosis.
A total of 35 patients with congenital AS (median age 16 years) and 27 normal control subjects (median age 16 years) were evaluated by CMR. ECV was calculated from pre- and post-gadolinium contrast T1 measurements of blood and myocardium, and the hematocrit.
ECV was significantly higher in AS patients than in normal subjects (median 0.27 [range 0.22 to 0.42] vs. 0.25 [range 0.18 to 0.27], p = 0.001). LGE was present in 8 (24%) of the AS patients. A higher ECV was correlated with echocardiographic indexes of diastolic dysfunction including a higher mitral E-wave z-score (r = 0.58, p = 0.002), E/septal E' z-score (r = 0.56, p = 0.003), E/mean E' z-score (r = 0.55, p = 0.003), and indexed left atrial volume (r = 0.56, p = 0.001). Other factors associated with an elevated ECV (>0.28) included a greater number of aortic valve interventions (p = 0.004) and a greater number of aortic valve balloon valvuloplasties (p = 0.003). ECV was not significantly associated with AS gradient, left ventricular mass, mass/volume ratio, or ejection fraction.
In young patients with AS, myocardial ECV is significantly elevated compared with control subjects and is associated with echocardiographic indexes of diastolic dysfunction. ECV measured by CMR may be a useful method for risk stratification and monitoring therapies targeting fibrosis.
本研究旨在分析先天性主动脉瓣狭窄（AS）患儿和年轻成人的心脏磁共振（CMR）心肌细胞外容积分数（ECV）和延迟钆增强（LGE）测量值，以确定纤维化程度，并探讨其与主动脉瓣和心室功能的关系。
患有先天性 AS 的患者常伴有舒张期心室功能障碍和运动能力受损，这可能与心肌纤维化有关。
共纳入 35 例先天性 AS 患者（中位年龄 16 岁）和 27 例正常对照者（中位年龄 16 岁），并进行 CMR 检查。ECV 通过血和心肌的钆对比前后 T1 测量值和红细胞压积计算得出。
AS 患者的 ECV 明显高于正常对照组（中位数 0.27 [范围 0.22 至 0.42] 比 0.25 [范围 0.18 至 0.27]，p = 0.001）。8 例（24%）AS 患者存在 LGE。较高的 ECV 与舒张功能障碍的超声心动图指标相关，包括较高的二尖瓣 E 波 z 评分（r = 0.58，p = 0.002）、E/间隔 E' z 评分（r = 0.56，p = 0.003）、E/平均 E' z 评分（r = 0.55，p = 0.003）和左心房容积指数（r = 0.56，p = 0.001）。与 ECV 升高（>0.28）相关的其他因素包括主动脉瓣介入治疗次数较多（p = 0.004）和主动脉瓣球囊扩张术次数较多（p = 0.003）。ECV 与 AS 梯度、左心室质量、质量/容积比或射血分数无显著相关性。
在年轻的 AS 患者中，心肌 ECV 明显高于对照组，与舒张功能障碍的超声心动图指标相关。CMR 测量的 ECV 可能是一种有用的风险分层方法，可用于监测针对纤维化的治疗效果。
