Chiang Chih-Yao, Lin Shen-Che, Hsu Jung-Cheng, Chen Jer-Shen, Huang Jih-Hsin, Chiu Kuan-Ming
Department of Cardiovascular Surgery, Cardiovascular Center, Far Eastern Memorial Hospital, New Taipei City 220216, Taiwan.
Division of Cardiovascular Surgery, Department of Surgery, School of Medicine, National Defense Medical Center, Taipei 114201, Taiwan.
J Clin Med. 2024 Jun 27;13(13):3777. doi: 10.3390/jcm13133777.
: In aortic stenosis, the left ventricle exerts additional force to pump blood through the narrowed aortic valve into the downstream arterial vasculature. Adaptive hypertrophy helps to maintain wall stress homeostasis but at the expense of impaired compliance. Advanced ventricular deformation impacts the extent of functional recovery benefits achieved through transcatheter aortic valve implantation. : Subgroups were stratified based on output, with low-flow severe aortic stenosis defined as stroke volume index <35 mL· m. Before intervention, the low-flow subgroup exhibited worse effective orifice area index and arterial and global impedance, along with thinner wall thickness and larger chamber volume marginally. LV performance, including stroke volume index, ventricular elastance, and ventricular-arterial coupling, were notably inferior, consistent with worse adverse remodeling. Although the effective orifice area index was similarly augmented after TAVI, inferior recovery benefits were noted. Persistently higher wall stress and energy consumption were observed, along with poorer ventricular-arterial coupling. These changes in wall stress showed an inverse relationship with alterations in wall thickness and were proportional to changes in dimension and volume. Additionally, they were proportional to changes in left ventricular end-systolic pressure, pressure-volume area, and ventricular-arterial coupling but inversely related to ventricular end-systolic elastance. : The study revealed that aortic valve enlargement through transcatheter aortic valve implantation reduces left ventricular wall stress in severe aortic stenosis. The reduced recovery benefits in the low-flow subgroup were evident. Wall stress could serve as a marker of mechanical benefit after the intervention.
在主动脉瓣狭窄中，左心室需施加额外的力将血液泵过狭窄的主动脉瓣进入下游动脉血管系统。适应性肥厚有助于维持壁应力稳态，但代价是顺应性受损。晚期心室变形会影响经导管主动脉瓣植入术所带来的功能恢复益处的程度。
根据心输出量对亚组进行分层，低流量严重主动脉瓣狭窄定义为每搏量指数<35 mL·m²。干预前，低流量亚组的有效瓣口面积指数、动脉和整体阻抗较差，同时壁厚度略薄，腔室容积略大。左心室功能，包括每搏量指数、心室弹性和心室-动脉耦合，明显较差，这与更严重的不良重塑一致。尽管经导管主动脉瓣植入术后有效瓣口面积指数同样增加，但恢复益处较差。观察到壁应力持续较高，能量消耗增加，心室-动脉耦合较差。这些壁应力变化与壁厚度变化呈负相关，与尺寸和容积变化成正比。此外，它们与左心室收缩末期压力、压力-容积面积和心室-动脉耦合的变化成正比，但与心室收缩末期弹性呈负相关。
该研究表明，经导管主动脉瓣植入术使主动脉瓣扩大可降低严重主动脉瓣狭窄患者的左心室壁应力。低流量亚组恢复益处较差是明显的。壁应力可作为干预后机械益处的一个指标。
