中海拔儿科Fontan患者心肌细胞外容积与运动耐量研究
回顾性队列研究纳入64例儿科Fontan患者与41例对照，分析CMR T1 mapping及ECV与运动耐量的关系。Fontan患者native T1和ECV均高于对照，VO₂ max显著降低，但ECV与VO₂ max在全队列中无显著相关。
要点
- Fontan患者心肌ECV升高，提示弥漫性心肌纤维化增加。
- ECV与运动耐量无显著相关，功能下降可能为多因素所致。
- Fontan术后时间与ECV呈负相关，随术后时间延长ECV反而降低。
核心结论
- Fontan患者心肌纤维化标志物native T1和ECV均高于健康对照。
- Fontan患者VO₂ max显著低于对照，运动耐量明显受损。
- ECV与运动耐量的关系复杂且呈亚组特异性，功能下降可能由多因素驱动。
研究设计与样本
- 回顾性队列研究，纳入2019至2022年间接受临床CMR检查的64例儿科Fontan患者，中位年龄11.0岁（IQR 7.0-14.0，<18岁）。
- 对照组为41例年龄及扫描仪匹配的儿科健康对照，按场强和心室优势进行分层。
- 使用CMR native T1和增强后T1 mapping定量全心native T1及ECV。
- 心肺运动试验VO₂ max及导管参数在CMR前后24个月内获取。
关键影像表现/征象
- Fontan患者native T1在1.5T（1035.9±48.7 ms vs 983.8±29.0 ms，P<0.001）和3T（1292.8±53.5 ms vs 1257.8±41.5 ms，P=0.033）均高于对照。
- Fontan患者ECV显著高于对照（25.6±3.5% vs 23.2±2.1%，P=0.007）。
- 右心室优势与左心室优势患者之间native T1和ECV无显著差异。
- Fontan患者VO₂ max显著降低（1.2±0.4 L/min vs 2.5±0.7 L/min，P<0.001）。
诊断标准与关键数值
- ECV与VO₂ max全队列相关未达统计学意义（R=-0.19，P>0.05）。
- Fontan术后时间与ECV呈负相关（R=-0.27，P<0.05）。
- native T1与运动耐量在局部亚组中呈现相关性。
临床应用与阅片要点
- Fontan患者CMR T1 mapping显示ECV升高可作为心肌纤维化的影像标志物。
- 解读ECV时需注意场强和心室优势分层的影响。
- ECV升高不等同于运动耐量下降，报告时避免过度推断功能意义。
局限性
- 回顾性单中心设计，样本量有限。
- 导管参数与CMR时间间隔可达24个月。
- ECV与VO₂ max缺乏全队列层面的显著相关，亚组特异性发现需进一步验证。
以上解读依据论文摘要（全文未开放获取或许可不允许翻译转载）。
英文原文（摘要）· 点击展开
BACKGROUND: Diffuse myocardial fibrosis, as measured by T1 (longitudinal relaxation time) mapping and extracellular volume, may be associated with ventricular dysfunction in the Fontan circulation. However, the relationship between diffuse myocardial fibrosis and exercise tolerance, an early and clinically meaningful marker of Fontan physiology, remains incompletely characterized, particularly in pediatric populations.
OBJECTIVE: To evaluate the association between CMR-derived markers of diffuse myocardial fibrosis (native T1 and ECV) and exercise tolerance in pediatric patients with Fontan circulation compared with healthy controls.
MATERIALS AND METHODS: A retrospective cohort study of pediatric patients with Fontan circulation who underwent clinically indicated cardiovascular magnetic resonance (CMR) with native and post-contrast T1 mapping between 2019 and 2022 was performed. Global native T1 and ECV were quantified and compared with age- and scanner-matched controls. Cardiopulmonary exercise testing-derived VO₂ max and catheterization parameters obtained within 24 months of CMR were analyzed. Associations between myocardial fibrosis markers and functional measures were assessed using correlation analyses.
RESULTS: A cohort of 64 pediatric Fontan patients (median age 11.0 years, interquartile range 7.0-14.0; age range <18 years), and 41 pediatric controls, was stratified by field strength and ventricular dominance. Fontan patients demonstrated increased native T1 values across varying field strengths of 1.5 T (1,035.9 ± 48.7 ms vs 983.8 ± 29.0 ms, P<0.001) and 3 T (1,292.8 ± 53.5 ms vs 1,257.8 ± 41.5 ms, P=0.033), and significantly elevated ECV compared to controls (25.6 ± 3.5% vs 23.2 ± 2.1%, P=0.007). There was no significant difference in native T1 or ECV between dominant right and left ventricles. VO₂ max was markedly reduced in Fontan patients compared to controls (1.2 ± 0.4 liters per minute (LPM) vs 2.5 ± 0.7 LPM, P<0.001). While a broad-inverse correlation between ECV and VO₂ max did not reach statistical significance across the full cohort (R=-0.19, P>0.05), time since Fontan surgery was inversely correlated with ECV (R=-0.27, P<0.05), and localized subgroup correlations emerged between native T1 and exercise capacity.
CONCLUSIONS: Markers of myocardial fibrosis were elevated among Fontan patients compared to healthy controls. Fontan patients were shown to have reduced exercise tolerance compared to controls as measured by VO2 max. While myocardial ECV is elevated in pediatric Fontan patients, its relationship with impaired exercise capacity is complex and subgroup-specific, suggesting a need for additional study and functional decline may be driven by multifactorial etiologies.
引用
- Arnouts, Drysdale, Gerstner Saucedo, et al. Examination of elevated myocardial extracellular volume and exercise capacity in pediatric Fontan patients at moderate altitude. Pediatr Radiol. 2026. PMID: 42233987. doi:10.1007/s00247-026-06675-2
供执业医师工作参考，不替代临床判断；数值与分级以指南原文为准。