Department of Chemical Engineering, McGill University, Montreal, Quebec, Canada; Research Center, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada.
Research Center, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada; Division of Cardiac Surgery, Montreal Heart Institute, Université de Montréal, Canada.
Cardiovasc Pathol. 2017 Jul-Aug;29:48-52. doi: 10.1016/j.carpath.2017.05.006. Epub 2017 May 30.
Type A aortic dissection is an acute condition that requires urgent surgical intervention. However, in a subset of patients, aortic dissections go undiagnosed and become chronic, thereby allowing the dissected wall to undergo a distinct remodeling process from that of the surrounding intact wall. Here, we observe the biomechanical and histological changes in the aortic wall of two patients with chronic Type A aortic dissection. Partial or complete disruption of the elastic structure of the medial layer was observed in the dissected wall of both patients; however, aortic stiffness in the region of dissection covaried with a change in collagen content. A ~50% increase in viscous energy loss was observed in the region of dissection of both patients which suggests an impaired elastic recoil and Windkessel function of the proximal aorta. MMP expression (2 and 9) differed between the dissected and intact wall and was distinct between the two patients. Our observations suggest that an active remodeling process occurs in the dissected aortic wall resulting in a vastly different biomechanical behavior.
A型主动脉夹层是一种需要紧急外科干预的急性病症。然而，在一部分患者中，主动脉夹层未被诊断，并发展为慢性，从而使夹层壁经历与周围完整壁不同的重塑过程。在这里，我们观察了两名慢性 A 型主动脉夹层患者的主动脉壁的生物力学和组织学变化。两名患者的夹层壁均观察到中层弹性结构的部分或完全破坏；然而，夹层区域的主动脉僵硬度与胶原含量的变化相关。两名患者的夹层区域均观察到粘性能量损失增加约 50%，这表明近端主动脉的弹性回弹和缓冲功能受损。MMP 表达（2 和 9）在夹层壁和完整壁之间存在差异，并且在两名患者之间也存在差异。我们的观察表明，在夹层主动脉壁中发生了活跃的重塑过程，导致了截然不同的生物力学行为。
