OBJECTIVES The goal of this study was to evaluate the prognostic value of global longitudinal strain (GLS) derived from cardiac magnetic resonance (CMR) feature-tracking in a large multicenter population of patients with preserved ejection fraction. BACKGROUND Ejection fraction is the principal parameter used clinically to assess cardiac mechanics and provides prognostic information. However, significant abnormalities of myocardial deformation can be present despite preserved ejection fraction. CMR feature-tracking techniques now allow assessment of strain from routine cine images, without specialized pulse sequences. Whether abnormalities of strain measured by using CMR feature-tracking have prognostic value in patients with preserved ejection fraction is unknown. METHODS Consecutive patients with preserved ejection fraction (≥50%) and a clinical indication for CMR at 4 U.S. medical centers were included in this retrospective study. Feature-tracking GLS was calculated from 3 long-axis cine views. The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the independent association between GLS and death. The incremental prognostic value of GLS was assessed in nested models. RESULTS Of the 1,274 patients in this study, 115 died during a median follow-up of 6.2 years. By Kaplan-Meier analysis, patients with GLS ≥ median (-20%) had significantly reduced event-free survival compared with those with GLS < median (log-rank test, p < 0.001). By Cox multivariable regression modeling, each 1% worsening in GLS was associated with a 22.8% increased risk of death after adjustment for clinical and imaging risk factors (hazard ratio: 1.228 per percent; p < 0.001). Addition of GLS in this model resulted in significant improvement in the global chi-square test (94 to 183; p < 0.001) and Harrell's C-statistic (0.75 to 0.83; p < 0.001). CONCLUSIONS GLS derived from CMR feature-tracking is a powerful independent predictor of mortality in patients with preserved ejection fraction, incremental to common clinical and imaging risk factors.

中文翻译：

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功能跟踪全球纵向应变预测射血分数保留患者的死亡率：一项多中心研究。

目的本研究的目的是评估在射血分数保留的大型多中心患者中源自心脏磁共振（CMR）特征追踪的全球纵向应变（GLS）的预后价值。背景技术射血分数是临床上用于评估心脏力学并提供预后信息的主要参数。然而，尽管保留了射血分数，但仍可能存在明显的心肌变形异常。CMR特征跟踪技术现在可以评估常规电影图像中的应变，而无需专门的脉冲序列。尚不清楚通过使用CMR特征跟踪测量的应变异常对射血分数保留的患者是否具有预后价值。方法这项回顾性研究包括连续射血分数（≥50％）并在美国4个医疗中心接受CMR临床指征的患者。从3个长轴电影视图中计算出了特征跟踪GLS。主要终点是全因死亡。使用Cox比例风险回归模型来检验GLS与死亡之间的独立关联。在嵌套模型中评估了GLS的增加的预后价值。结果在本研究的1,274名患者中，有115名在6.2年的中位随访期间死亡。通过Kaplan-Meier分析，与GLS <中位数（对数秩检验，p <0.001）相比，GLS≥中位数（-20％）的患者无事件生存期显着降低。通过Cox多变量回归模型，GLS每增加1％，就会导致22岁。在调整了临床和影像学危险因素后，死亡风险增加了8％（危险比：1.228个百分点； p <0.001）。在该模型中添加GLS导致整体卡方检验（94至183； p <0.001）和Harrell的C统计量（0.75至0.83； p <0.001）有了显着改善。结论从CMR特征跟踪得出的GLS是射血分数得以保留，对常见临床和影像学危险因素具有增量作用的患者死亡率的有力独立预测指标。