Columbia University Medical Center, Cardiology Department, 622 W. 168th Street, PH3-133, New York, NY 10032, USA.
J Am Soc Echocardiogr. 2012 Feb;25(2):153-9. doi: 10.1016/j.echo.2011.11.003. Epub 2011 Nov 30.
It has been suggested that myocardial systolic impairment may not be accurately detected by the evaluation of endocardial excursion alone. The aim of this study was to test the hypothesis that changes in left ventricular (LV) subendocardial and subepicardial strain are sensitive markers of severity of aortic stenosis (AS) and LV function in patients with AS.
Transthoracic echocardiography was performed in 73 consecutive patients with AS who had preserved systolic function and in 20 controls. Longitudinal strain, subendocardial radial strain, subepicardial radial strain, and transmural radial strain were measured using LV apical and short-axis images.
The 73 patients enrolled in this study were classified according to AS severity: mild (n = 10), moderate (n = 15), or severe (n = 48). Although transmural and subepicardial radial strain showed similar values in all groups, subendocardial radial strain and longitudinal strain could differentiate mild or moderate AS from severe AS. Only the ratio of subendocardial to subepicardial radial strain (the bilayer ratio) decreased significantly as the severity of AS increased. Bilayer ratio showed weak correlations with LV ejection fraction (r = 0.37) and E/E' ratio (r = -0.33) and moderate correlations with LV mass (r = -0.55) and aortic valve area (r = 0.71). Moreover, bilayer ratio was independently associated with AS severity (P = .001). In 21 patients who underwent aortic valve replacement, subendocardial radial strain and bilayer ratio increased 7 days after surgery, whereas other echocardiographic parameters of LV function showed no improvement.
Bilayer ratio can reliably differentiate patients with varying degrees of AS severity and is a sensitive marker of LV function. These findings suggest that the evaluation of subendocardial and subepicardial radial strain might be a novel method for assessing LV mechanics in patients with AS.
有人认为，仅仅通过评估心内膜位移，可能无法准确检测心肌收缩功能障碍。本研究旨在验证以下假设，即左心室（LV）心内膜下和心外膜下应变的变化是主动脉瓣狭窄（AS）严重程度和 AS 患者 LV 功能的敏感标志物。
对 73 例连续患有 AS 且收缩功能正常的患者和 20 例对照者进行经胸超声心动图检查。使用 LV 心尖和短轴图像测量纵向应变、心内膜下径向应变、心外膜下径向应变和跨壁径向应变。
这项研究共纳入了 73 名患者，根据 AS 严重程度进行分类：轻度（n = 10）、中度（n = 15）或重度（n = 48）。尽管所有组的跨壁和心外膜下径向应变值相似，但心内膜下径向应变和纵向应变可以区分轻度或中度 AS 与重度 AS。只有心内膜下心外膜下径向应变比值（双层比值）随着 AS 严重程度的增加而显著降低。双层比值与 LV 射血分数（r = 0.37）和 E/E' 比值（r = -0.33）呈弱相关，与 LV 质量（r = -0.55）和主动脉瓣口面积（r = 0.71）呈中度相关。此外，双层比值与 AS 严重程度独立相关（P =.001）。在 21 例行主动脉瓣置换术的患者中，术后 7 天心内膜下径向应变和双层比值增加，而其他 LV 功能的超声心动图参数没有改善。
双层比值能可靠地区分不同程度 AS 患者，是 LV 功能的敏感标志物。这些发现表明，评估心内膜下和心外膜下径向应变可能是评估 AS 患者 LV 力学的一种新方法。
