Kim Hyun-Jin, Lee Seung-Pyo, Park Chan Soon, Park Jun-Bean, Kim Yong-Jin, Kim Hyung-Kwan, Sohn Dae-Won
Department of Internal Medicine, Cardiovascular Center, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, South Korea.
Department of Cardiology, Myongji Hospital, 697-24 Hwajung-dong, Deokyang-gu, Goyang-si, Gyeonggi-do, 412-270, South Korea.
Int J Cardiovasc Imaging. 2016 Feb;32(2):247-259. doi: 10.1007/s10554-015-0759-y. Epub 2015 Sep 1.
The present study evaluated change in left ventricle (LV) biomechanics, layer-by-layer, following acute pressure unloading in patients with severe aortic stenosis (AS). In twenty-eight consecutive patients with severe AS who underwent transcatheter aortic valve replacement (TAVR), LV peak global longitudinal and circumferential strains of the endo-, midmyo- and epicardium were evaluated using multilayer speckle tracking echocardiography before, 1 week after, and 1 month after TAVR. Longitudinal and circumferential strains were significantly highest in the endocardium and lowest in the epicardium at baseline. At 1 month following TAVR, longitudinal strain significantly improved in all layers compared with the baseline [endocardium (%) -16.7 ± 3.8 vs. -18.6 ± 3.3, P = 0.01; mid-myocardium -14.4 ± 3.2 vs. -16.2 ± 3.5, P < 0.01; epicardium -12.4 ± 2.8 vs. -13.6 ± 2.6, P = 0.01], whereas LV ejection fraction and circumferential strain remained unchanged. Importantly, only those with LV hypertrophy demonstrated improved longitudinal strain [endocardium (%) -15.7 ± 3.0 vs. -18.7 ± 2.9, P < 0.01; mid-myocardium -13.6 ± 2.7 vs. -16.0 ± 2.5, P < 0.01; epicardium -11.8 ± 2.4 vs. -13.7 ± 2.3, P < 0.01]. The improvement in longitudinal strain was more prominent in the endocardium, which was evident even at an early time point (1 week) after TAVR. Longitudinal strain significantly improved in all three layers following acute pressure unloading, the most prominent of which was observed in the endocardium. Evaluation of multilayer strain may provide new insights into the LV mechanics in the future.
本研究评估了严重主动脉瓣狭窄（AS）患者急性压力卸载后左心室（LV）各层生物力学的变化。在连续28例接受经导管主动脉瓣置换术（TAVR）的严重AS患者中，在TAVR术前、术后1周和术后1个月，使用多层斑点追踪超声心动图评估心内膜、心肌中层和心外膜的左心室整体纵向和圆周应变峰值。基线时，纵向和圆周应变在心内膜中显著最高，在心外膜中最低。TAVR术后1个月，与基线相比，所有层的纵向应变均显著改善[心内膜（%）-16.7±3.8 vs. -18.6±3.3，P = 0.01；心肌中层-14.4±3.2 vs. -16.2±3.5，P < 0.01；心外膜-12.4±2.8 vs. -13.6±2.6，P = 0.01]，而左心室射血分数和圆周应变保持不变。重要的是，只有左心室肥厚患者的纵向应变得到改善[心内膜（%）-15.7±3.0 vs. -18.7±2.9，P < 0.01；心肌中层-13.6±2.7 vs. -16.0±2.5，P < 0.01；心外膜-11.8±2.4 vs. -13.7±2.3，P < 0.01]。纵向应变的改善在心内膜中更为显著，甚至在TAVR术后早期（1周）就很明显。急性压力卸载后，所有三层的纵向应变均显著改善，其中最显著的是在心内膜中。多层应变评估可能为未来左心室力学提供新的见解。
