Background

Speckle tracking strain echocardiography allows one to visualize the timing of maximum regional strain and quantifies left ventricular-mechanical dispersion (LV-MD). Whether LV-MD and LV-global longitudinal strain (LV-GLS) provide similar or complementary information in mortality risk stratification in patients with severe aortic stenosis (SAS) remains unknown.

Objectives

We hypothesized that LV mechanical dyssynchrony assessed by LV-MD is associated with an increased risk of mortality and provides additional prognostic information on top of LV-GLS in patients with SAS.

Methods

A total of 364 patients with SAS (aortic valve area indexed ≤0.6 cm²/m² and/or aortic valve area ≤1 cm²), LV ejection fraction ≥50% and no or mild symptoms were enrolled. The endpoint was overall mortality.

Results

During a median follow-up period of 41 months, 149 patients died. After adjustment, LV-MD ≥68 ms was significantly associated with an increased risk of mortality (adjusted HR: 1.41; 95% CI: 1.01-1.96; P = 0.044). Adding LV-MD ≥68 ms to a multivariable Cox regression model including LV-GLS ≥−15% improved predictive performance in terms of overall mortality, with improved global model fit, reclassification, and better discrimination. Patients with both criteria had an important increase in mortality compared to patients with none or one criterion (adjusted HR: 2.02; 95% CI: 1.34-3.03; P = 0.001). Interobserver reproducibility of LV-MD was good with an intraclass correlation coefficient of 0.90 (95% CI: 0.72-0.97).

Conclusions

LV-MD is a reproducible parameter independently associated with an increased risk of mortality in SAS. Increased LV-MD associated with depressed LV-GLS identifies a subgroup of patients with an increased mortality risk. Whether early aortic valve replacement improves the outcome of these patients deserves further studies.

中文翻译：

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严重主动脉瓣狭窄患者左心室弥散和变形的附加预后价值

背景

斑点跟踪应变超声心动图允许人们可视化最大区域应变的时间并量化左心室机械分散（LV-MD）。LV-MD 和 LV-GLS 是否在严重主动脉瓣狭窄 (SAS) 患者的死亡风险分层中提供相似或互补的信息仍不清楚。

目标

我们假设 LV-MD 评估的左室机械不同步与死亡风险增加相关，并为 SAS 患者提供除 LV-GLS 之外的额外预后信息。

方法

共有364例SAS患者（主动脉瓣面积指数≤0.6 cm ² /m ²和/或主动脉瓣面积≤1 cm ²）、左心室射血分数≥50%且无症状或症状轻微的患者入组。终点是总体死亡率。

结果

在 41 个月的中位随访期内，149 名患者死亡。调整后，LV-MD ≥68 ms 与死亡风险增加显着相关（调整后 HR：1.41；95% CI：1.01-1.96；P  = 0.044）。将 LV-MD ≥68 ms 添加到多变量 Cox 回归模型（包括 LV-GLS ≥−15%）可提高总体死亡率方面的预测性能，并改善全局模型拟合、重新分类和更好的区分度。与没有或只有一项标准的患者相比，同时具备两项标准的患者死亡率显着增加（调整后 HR：2.02；95% CI：1.34-3.03；P  = 0.001）。LV-MD 的观察者间重现性良好，组内相关系数为 0.90（95% CI：0.72-0.97）。

结论

LV-MD 是一个可重复的参数，与 SAS 死亡风险增加独立相关。LV-MD 增加与 LV-GLS 降低相关，可确定死亡风险增加的患者亚组。早期主动脉瓣置换术是否可以改善这些患者的预后值得进一步研究。