Is Biventricular Fibrosis the Mediator of Late Complications in Tetralogy of Fallot?
Is Biventricular Fibrosis the Mediator of Late Complications in Tetralogy of Fallot?
复制标题
双心室纤维化是法洛四联症晚期并发症的媒介吗？
DOI：
10.1016/j.jcmg.2015.08.017
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Gregg,David
中科院分区：
文献类型：
--
作者：
Zile,MichaelR;Gregg,David
儿童法洛四联症（TOF）修复术是先天性心脏病手术的最大成功之一，现在有90%以上的患者存活至成年（1）。然而，包括猝死、房性和室性心律失常和心力衰竭在内的晚期并发症持续存在。在儿童期修复后，大多数TOF患者留下肺动脉返流。最初，即使是严重的肺动脉返流也能很好地耐受，通常在20至30年内相对无症状，但随后出现晚期并发症（2）。尚不清楚是什么变化介导了症状的发作和晚期失代偿。大多数研究表明，残余肺动脉瓣反流与右心室扩大有关，但引起症状、心力衰竭和不良结局的原因尚不清楚。越来越多的证据表明，细胞外基质（ECM）的变化和心室纤维化可能在介导下降中发挥重要作用，并可能成为潜在的干预目标或指导晚期肺动脉瓣置换术或其他治疗干预的理想时机。使用磁共振成像（MRI）晚期钆增强（LGE）定量局灶性纤维化，LGE增加与疾病严重程度相关（3）。然而，LGE没有显示心肌细胞外弥漫性变化的程度，可能低估了ECM的变化。MRI T1标测已越来越多地用于计算各种心血管状态下的细胞外容积（ECV）分数，包括心力衰竭、心律失常和肺动脉高压。MRI衍生的ECV与组织学整体纤维化密切相关，可以作为心肌纤维化的有用标志物，T1衍生的ECV与心力衰竭和心律失常的预后不良相关（4）。在本期iJACC中，2篇论文深入了解了TOF晚期并发症的可能机制，并深入了解了双心室功能障碍中的左心室和右心室相互作用。这两篇论文都使用MRI T1标测来研究弥漫性心室纤维化，以计算修复的TOF中的ECV，并评估与临床状态和血流动力学的关系。Chen等人(5)研究双心室纤维化，计算左心室和右心室的细胞外容积分数，而Broberg et al. (6)局限于左心室的评估，对TOF中左右侧相互依赖的重要性感兴趣。我们很想看到特别是右心MRI衍生ECV的研究，因为薄壁右心室可能会带来独特的成像挑战。每个小组所研究的人口有很大的不同，这可能会影响结论和调查结果。也许，最重要的是，在Broberg等人的队列。(6)研究是一个比Chen等人的队列年龄大得多的组（平均年龄40岁）。（5）（平均年龄23岁），初次修复的年龄也相当晚。The Broberg et al. (6)因此，初次手术治疗延迟的队列更能反映既往治疗情况，而Chen等人的队列更能反映既往治疗情况。(5)更接近现代护理，TOF的早期修复现在是护理标准。
Childhood repair of tetralogy of Fallot (TOF) is one of the great successes of congenital heart surgery, with now> 90% of patients surviving to adulthood (1). Late complications including sudden death, atrial and ventricular arrhythmias, and heart failure, however, persist. After childhood repair, most patients with TOF are left with pulmonary regurgitation. Initially, even severe pulmonary regurgitation is well tolerated with usually a relatively asymptomatic period for 20 to 30 years, but then late complications arise (2). It is not clear what changes mediate the onset of symptoms and late decompensation. Most studies have shown a link to residual pulmonary regurgitation with resultant right ventricular enlargement, but what triggers the development of symptoms, ventricular failure, and poor outcomes has been unclear. Increasing evidence suggests that extracellular matrix (ECM) changes and ventricular fibrosis may play an important role mediating the decline and could be either a potential target for intervention or a guide to the ideal timing of targeting late pulmonary valve replacement or other therapeutic interventions. Using magnetic resonance imaging (MRI) late gadolinium enhancement (LGE) to quantify focal fibrosis, increased LGE has shown correlation with severity of disease (3). LGE, however, does not show the extent of diffuse extracellular changes in the myocardium and likely underestimates ECM changes. Increasingly, MRI T1 mapping has been used to calculate extracellular volume (ECV) fraction in a variety of cardiovascular states including heart failure, arrhythmia, and pulmonary hypertension. MRI-derived ECV correlates well with histological global fibrosis and can be a useful marker of myocardial fibrosis, and T1-derived ECV has been correlated with worse prognosis in heart failure and arrhythmia (4).In this issue of iJACC, 2 papers provide insight into the possible mechanisms of late complications in TOF and give insight into left and right ventricular interaction in biventricular dysfunction. Both papers look at diffuse ventricular fibrosis using MRI T1 mapping to calculate ECV in repaired TOF and evaluate the relationship to clinical status and hemodynamics. Chen et al.(5) look at biventricular fibrosis calculating extracellular volume fraction in both the left and right ventricles, whereas Broberg et al.(6) limit themselves to an evaluation of the left ventricle, interested in the importance of left-and right-sided interdependence in TOF. We are intrigued to see studies validating in particular right heart MRI-derived ECV, as the thin-walled right ventricle may present unique imaging challenges. The populations studied by each group are quite different, which may affect conclusions and findings. Perhaps, most importantly, the cohort in the Broberg et al.(6) study is a much older group (mean age 40 years) than the cohort of Chen et al.(5)(mean age 23 years) and the age at initial repair is also considerably later. The Broberg et al.(6) cohort with delayed initial surgical treatment is therefore more reflective of historical care and the cohort of Chen et al.(5) is closer to contemporary care, with early repair of TOF now the standard of care.