Dilated cardiomyopathy (DCM) is increasingly recognized as a heterogenous disease with distinct phenotypes on late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging. While mid-wall striae (MWS) fibrosis is a widely recognized phenotypic risk marker, other fibrosis patterns are prevalent but poorly defined. Right ventricular (RV) insertion (RVI) site fibrosis is commonly seen, but without objective criteria has been considered a non-specific finding. In this study we developed objective criteria for RVI fibrosis and studied its clinical relevance in a large cohort of patients with DCM. We prospectively enrolled 645 DCM patients referred for LGE-CMR. All underwent standardized imaging protocols and baseline health evaluations. LGE images were blindly scored using objective criteria, inclusive of RVI site and MWS fibrosis. Associations between LGE patterns and CMR-based markers of adverse chamber remodeling were evaluated. Independent associations of LGE fibrosis patterns with the primary composite clinical outcome of heart failure admission or death were determined by multivariable analysis. The mean age was 56 ± 14 (28% female) with a mean left ventricular (LV) ejection fraction (LVEF) of 37%. At a median of 1061 days, 129 patients (20%) experienced the primary outcome. Any abnormal LGE was present in 306 patients (47%), inclusive of 274 (42%) meeting criteria for RVI site fibrosis and 167 (26%) for MWS fibrosis. All with MWS fibrosis showed RVI site fibrosis. Solitary RVI site fibrosis was associated with higher bi-ventricular volumes [LV end-systolic volume index (78 ± 39 vs. 66 ± 33 ml/m2, p = 0.01), RV end-diastolic volume index (94 ± 28 vs. 84 ± 22 ml/m2 (p < 0.01), RV end-systolic volume index (56 ± 26 vs. 45 ± 17 ml/m2, p < 0.01)], lower bi-ventricular function [LVEF 35 ± 12 vs. 39 ± 10% (p < 0.01), RV ejection fraction (RVEF) 43 ± 12 vs. 48 ± 10% (p < 0.01)], and higher extracellular volume (ECV). Patient with solitary RVI site fibrosis experienced a non-significant 1.4-fold risk of the primary outcome, increasing to a significant 2.6-fold risk when accompanied by MWS fibrosis. RVI site fibrosis in the absence of MWS fibrosis is associated with bi-ventricular remodelling and intermediate risk of heart failure admission or death. Our study findings suggest RVI site fibrosis to be pre-requisite for the incremental development of MWS fibrosis, a more advanced phenotype associated with greater LV remodeling and risk of clinical events.

中文翻译：

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扩张型心肌病转诊人群中的右心室插入部位纤维化：表型关联以及心力衰竭入院或死亡的预测价值


扩张型心肌病（DCM）越来越被认为是一种异质性疾病，在晚期钆增强（LGE）心血管磁共振（CMR）成像上具有不同的表型。虽然中壁条纹 (MWS) 纤维化是一种广泛认可的表型风险标志物，但其他纤维化模式也很普遍，但定义不明确。右心室（RV）插入（RVI）部位纤维化很常见，但如果没有客观标准，则被认为是非特异性发现。在这项研究中，我们制定了 RVI 纤维化的客观标准，并研究了其在大量 DCM 患者中的临床相关性。我们前瞻性地招募了 645 名转诊至 LGE-CMR 的 DCM 患者。所有患者均接受标准化成像方案和基线健康评估。 LGE 图像使用客观标准进行盲评分，包括 RVI 部位和 MWS 纤维化。评估了 LGE 模式与基于 CMR 的不良心室重塑标记之间的关联。通过多变量分析确定 LGE 纤维化模式与心力衰竭入院或死亡的主要复合临床结果的独立关联。平均年龄为 56 ± 14 岁（28% 为女性），平均左心室 (LV) 射血分数 (LVEF) 为 37%。中位时间为 1061 天，129 名患者 (20%) 经历了主要结局。 306 名患者 (47%) 存在任何异常 LGE，其中 274 名患者 (42%) 符合 RVI 部位纤维化标准，167 名患者 (26%) 符合 MWS 纤维化标准。所有患有 MWS 纤维化的患者均显示 RVI 部位纤维化。孤立性 RVI 部位纤维化与较高的双心室容积相关 [LV 收缩末期容积指数（78 ± 39 vs. 66 ± 33 ml/m2，p = 0.01），RV 舒张末期容积指数（94 ± 28 vs. 84） ± 22 ml/m2 (p < 0.01)，RV 收缩末期容积指数（56 ± 26 vs. 45 ± 17 ml/m2，p < 0。01)]，双心室功能降低 [LVEF 35 ± 12 vs. 39 ± 10% (p < 0.01)，RV 射血分数 (RVEF) 43 ± 12 vs. 48 ± 10% (p < 0.01)]，以及更高细胞外容量（ECV）。孤立性 RVI 部位纤维化患者的主要结局风险为非显着性 1.4 倍，而当伴有 MWS 纤维化时，风险增加至显着性 2.6 倍。在没有 MWS 纤维化的情况下，RVI 部位纤维化与双心室重构和心力衰竭入院或死亡的中等风险相关。我们的研究结果表明，RVI 部位纤维化是 MWS 纤维化逐渐发展的先决条件，MWS 纤维化是一种与更大的 LV 重塑和临床事件风险相关的更高级的表型。