Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Mie, Japan.
Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Mie, Japan.
JACC Cardiovasc Imaging. 2020 Oct;13(10):2117-2128. doi: 10.1016/j.jcmg.2020.05.030. Epub 2020 Aug 5.
This study sought to evaluate the potential of cardiac magnetic resonance T mapping to detect load-independent left ventricular (LV) chamber stiffness by histological confirmation.
Accurate noninvasive diagnosis of LV diastolic dysfunction in heart failure with preserved ejection fraction (HFpEF) remains challenging.
Nineteen HFpEF patients (14 female, 65 ± 16 years of age) without primary cardiomyopathy were prospectively enrolled. Cine, late gadolinium enhancement cardiac magnetic resonance, and triple-slice T mapping using a modified Look-Locker inversion recovery sequence were performed at 3-T. Extracellular volume (ECV) was quantified from pre- and post-contrast T values of the blood and myocardium with hematocrit correction. LV stiffness constant (beta) was assessed by calculating the slope of the end-diastolic pressure-volume relationship curve during vena cava occlusion. Biopsy samples were used for quantification of collagen volume fraction (CVF) and myocardial cell size.
Six patients showed focal scar on late gadolinium enhancement. There was no significant difference in histological CVF between patients with and without focal myocardial scarring (p = 0.2). Septal ECV rather than native T was a better surrogate marker for detecting histological CVF (r = 0.54; p = 0.02, and r = 0.44; p = 0.06, respectively). Global native T and ECV, but not native T and ECV in the septal myocardium, correlated well with the beta of passive LV stiffness, and had similar ability for predicting LV stiffness to histological CVF (r = 0.54, 0.50, 0.53, all p < 0.05, respectively). When the beta ≥0.054 was considered as moderately increased LV stiffness, global native T ≥1,362 ms provided 88% sensitivity and 64% specificity with the C-statistic of 0.81 (95% confidence interval: 0.56 to 0.95).
Myocardial native T provides comparable ability in predicting LV stiffness to ECV and histological CVF and may be useful for monitoring patients with HFpEF who have renal dysfunction, allergy to gadolinium, or wheezing that can simulate asthma. Our feasibility study shows the potential of native T to allow for insight of heterogeneous pathophysiology and better risk stratification of HFpEF.
本研究旨在通过组织学确认评估心脏磁共振 T 映射检测负荷独立左心室（LV）腔僵硬的潜力。
准确无创诊断射血分数保留的心衰（HFpEF）中的 LV 舒张功能障碍仍然具有挑战性。
前瞻性纳入 19 例无原发性心肌病的 HFpEF 患者（14 名女性，65±16 岁）。在 3-T 上进行电影、晚期钆增强心脏磁共振和使用改良 Look-Locker 反转恢复序列的三切片 T 映射。通过血细胞比容校正从血液和心肌的预对比和后对比 T 值量化细胞外容积（ECV）。通过计算腔静脉闭塞期间舒张末期压力-容积关系曲线的斜率评估 LV 僵硬常数（β）。使用活检样本定量胶原容积分数（CVF）和心肌细胞大小。
6 例患者在晚期钆增强上显示局灶性瘢痕。有和没有局灶性心肌瘢痕的患者之间组织学 CVF 无显著差异（p=0.2）。间隔 ECV 而不是固有 T 是检测组织学 CVF 的更好替代标志物（r=0.54；p=0.02 和 r=0.44；p=0.06）。整体固有 T 和 ECV，而不是间隔心肌的固有 T 和 ECV，与 LV 被动僵硬的β相关性良好，并且具有与组织学 CVF 相似的预测 LV 僵硬的能力（r=0.54，0.50，0.53，所有 p<0.05）。当β≥0.054 被认为是中度增加的 LV 僵硬时，整体固有 T≥1,362ms 提供了 88%的敏感性和 64%的特异性，C 统计量为 0.81（95%置信区间：0.56 至 0.95）。
心肌固有 T 提供了与 ECV 和组织学 CVF 相当的预测 LV 僵硬的能力，可能对监测肾功能不全、对钆过敏或模拟哮喘的喘息的 HFpEF 患者有用。我们的可行性研究表明，固有 T 具有潜在的能力，可以深入了解异质病理生理学并更好地分层 HFpEF 的风险。
