Background:The high accuracy of feature-tracking cardiac magnetic resonance (CMR) imaging qualifies this novel modality as potential gold standard for myocardial strain analyses in ST-elevation myocardial infarction patients; however, the incremental prognostic validity of feature-tracking-CMR over left ventricular ejection fraction (LVEF) and myocardial damage remains unclear. This study therefore aimed to determine the value of myocardial strain measured by feature-tracking-CMR for the prediction of clinical outcome following ST-elevation myocardial infarction.Methods:This prospective observational study enrolled 451 revascularized ST-elevation myocardial infarction patients. Comprehensive CMR investigations were performed 3 (interquartile range, 2–4) days after infarction to determine LVEF, global longitudinal strain (GLS), global radial strain, and global circumferential strain as well as myocardial damage. Primary end point was a composite of death, re-infarction, and congestive heart failure (major adverse cardiac events [MACE]).Results:During a follow-up of 24 (interquartile range, 11–48) months, 46 patients (10%) experienced a MACE event. All 3 strain indices were impaired in patients with MACE (all P<0.001). However, GLS emerged as the strongest MACE prognosticator among strain parameters (area under the curve, 0.73 [95% CI, 0.69–0.77]) and was significantly better (P=0.005) than LVEF (area under the curve, 0.64 [95% CI, 0.59–0.68]). The association between GLS and MACE remained significant (P<0.001) after adjustment for global radial strain, global circumferential strain, and LVEF as well as for infarct size and microvascular obstruction. The addition of GLS to a risk model comprising LVEF, infarct size, and microvascular obstruction led to a net reclassification improvement (0.35 [95% CI, 0.14–0.55]; P<0.001).Conclusions:GLS by feature-tracking-CMR strongly and independently predicted the occurrence of medium-term MACE in contemporary revascularized ST-elevation myocardial infarction patients. Importantly, the prognostic value of GLS was superior and incremental to LVEF and CMR markers of infarct severity.

中文翻译：

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功能跟踪心脏磁共振在ST抬高型心肌梗死中的全球纵向应变的预后意义。

背景：特征跟踪心脏磁共振（CMR）成像的高精度使其成为ST抬高型心肌梗死患者心肌应变分析的潜在金标准。然而，特征跟踪CMR对左心室射血分数（LVEF）和心肌损害的递增预后有效性尚不清楚。因此，本研究旨在确定通过特征跟踪CMR测量的心肌应变值，以预测ST抬高型心肌梗死后的临床结果。方法：这项前瞻性观察性研究招募了451名血运重建的ST抬高型心肌梗死患者。在梗塞后第3天（四分位间距，2-4天）进行了全面的CMR调查，以确定LVEF，总纵向应变（GLS），总径向应变，和整体圆周应变以及心肌损伤。主要终点是死亡，再梗塞和充血性心力衰竭（重大不良心脏事件[MACE]）的综合结果。结果：在接下来的24个月（四分位间距为11-48）内进行随访，共46例患者（10例） ％）经历了一次MACE事件。MACE患者的所有3个菌株指标均受损（所有P <0.001）。但是，GLS成为应变参数中最强的MACE预后因子（曲线下面积0.73 [95％CI，0.69-0.77]），并且比LVEF（曲线下面积0.64 [95％]）明显更好（P = 0.005）。 CI，0.59–0.68]）。在对总径向应变，总周向应变和LVEF以及梗死面积和微血管阻塞进行调整后，GLS和MACE之间的相关性仍然很显着（P <0.001）。在包括LVEF，梗死面积和微血管阻塞的风险模型中添加GLS导致净重分类改善（0.35 [95％CI，0.14-0.55]；P<0.001）。结论：通过特征跟踪CMR进行的GLS强烈且独立地预测了当代经血运重建的ST抬高型心肌梗死患者的中期MACE发生率。重要的是，GLS的预后价值优于梗死严重程度的LVEF和CMR指标，且具有递增性。