Xu Ran, Ding Zhiwen, Li Hao, Shi Jing, Cheng Leilei, Xu Huixiong, Wu Jian, Zou Yunzeng
Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, China.
State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Front Cardiovasc Med. 2023 Jan 13;9:1071249. doi: 10.3389/fcvm.2022.1071249. eCollection 2022.
Aortic stenosis and regurgitation are clinically important conditions characterized with different hypertrophic types induced by pressure or volume overload, respectively, but with comparable cardiac function in compensated stage. Speckle-tracking based strain imaging has been applied to assess subtle alterations in cardiac abnormality, but its application in differentiating these two types of ventricular hypertrophy is still sparse. Here, we performed strain imaging analysis of cardiac remodeling in these two loading conditions.
C57BL/6J mice were subjected to transverse aortic constriction (TAC)-induced pressure overload or aortic regurgitation (AR)-induced volume overload. Conventional echocardiography and strain imaging were comprehensively assessed to detect stimulus-specific alterations in TAC and AR hearts.
Conventional echocardiography did not detect significant changes in left ventricular systolic (ejection fraction and fractional shortening) and diastolic (E/E') function in either TAC or AR mice. On the contrary, global strain analysis revealed global longitudinal strain and strain rate were remarkably impaired in TAC while preserved in AR mice, although global radial, and circumferential strain and strain rate were significantly reduced in both models. Regional strain analysis in the long axis demonstrated that longitudinal strain and strain rate in all or most segments were decreased in TAC but maintained or slightly dented in AR mice, while radial strain and strain rate indicated overt decline in both models. Moreover, decreased radial and circumferential strain and strain rate were observed in most segments of TAC and AR mice in the short axis.
Strain imaging is superior to conventional echocardiography to detect subtle changes in myocardial deformation, with longitudinal strain and strain rate indicating distinct functional changes in pressure versus volume overload myocardial hypertrophy, making it potentially an advanced approach for early detection and differential diagnosis of cardiac dysfunction.
主动脉狭窄和反流是临床上重要的病症，分别以压力或容量超负荷诱导的不同肥厚类型为特征，但在代偿期心脏功能相当。基于斑点追踪的应变成像已被用于评估心脏异常的细微变化，但其在区分这两种类型的心室肥厚中的应用仍然较少。在此，我们对这两种负荷条件下的心脏重塑进行了应变成像分析。
对C57BL/6J小鼠进行经胸主动脉缩窄（TAC）诱导的压力超负荷或主动脉反流（AR）诱导的容量超负荷。综合评估传统超声心动图和应变成像，以检测TAC和AR心脏中刺激特异性改变。
传统超声心动图未检测到TAC或AR小鼠左心室收缩功能（射血分数和缩短分数）和舒张功能（E/E'）有显著变化。相反，整体应变分析显示，TAC小鼠的整体纵向应变和应变率显著受损，而AR小鼠则保持正常，尽管两种模型的整体径向、圆周应变和应变率均显著降低。长轴区域应变分析表明，TAC小鼠所有或大部分节段的纵向应变和应变率降低，而AR小鼠保持或略有凹陷，而两种模型的径向应变和应变率均明显下降。此外，在短轴上，TAC和AR小鼠的大多数节段均观察到径向和圆周应变及应变率降低。
应变成像在检测心肌变形的细微变化方面优于传统超声心动图，纵向应变和应变率表明压力与容量超负荷心肌肥厚存在明显的功能变化，使其有可能成为早期检测和鉴别诊断心脏功能障碍的先进方法。
