Grewal Nimrat, Velders Bart J J, Gittenberger-de Groot Adriana C, Poelmann Robert, Klautz Robert J M, Van Brakel Thomas J, Lindeman Jan H N
Department of Cardiothoracic Surgery, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.
Department of Anatomy and Embryology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.
J Cardiovasc Dev Dis. 2021 Jan 27;8(2):12. doi: 10.3390/jcdd8020012.
(1) Background: The pathophysiologic basis of an acute type A aortic dissection (TAAD) is largely unknown. In an effort to evaluate vessel wall defects, we systematically studied aortic specimens in TAAD patients. (2) Methods: Ascending aortic wall specimens ( = 58, mean age 63 years) with TAAD were collected. Autopsy tissues ( = 17, mean age 63 years) served as controls. All sections were studied histopathologically. (3) Results: Pathomorphology in TAAD showed predominantly moderate elastic fiber fragmentation/loss, elastic fiber thinning, elastic fiber degeneration, mucoid extracellular matrix accumulation, smooth muscle cell nuclei loss, and overall medial degeneration. The control group showed significantly fewer signs of those histopathological features (none-mild, = 0.00). It was concluded that the dissection plane consistently coincides with the vasa vasorum network, and that TAAD associates with a significantly thinner intimal layer = 0.005). (4) Conclusions: On the basis of the systematic evaluation and the consistent presence of diffuse, pre-existing medial defects, we hypothesize that TAAD relates to a developmental defect of the ascending aorta and is caused by a triple-hit mechanism that involves (I) an intimal tear; and (II) a diseased media, which allows (III) propagation of the tear towards the plane of the vasa vasorum where the dissection further progresses.
(1) 背景：急性A型主动脉夹层（TAAD）的病理生理基础很大程度上尚不明确。为了评估血管壁缺陷，我们系统地研究了TAAD患者的主动脉标本。(2) 方法：收集了58例TAAD患者的升主动脉壁标本（平均年龄63岁）。尸检组织（17例，平均年龄63岁）作为对照。所有切片均进行了组织病理学研究。(3) 结果：TAAD的病理形态学主要表现为中度弹性纤维断裂/缺失、弹性纤维变薄、弹性纤维变性、黏液样细胞外基质积聚、平滑肌细胞核丢失以及整体中层退变。对照组这些组织病理学特征的表现明显较少（无-轻度，P = 0.00）。得出的结论是，夹层平面始终与滋养血管网络一致，且TAAD与明显更薄的内膜层相关（P = 0.005）。(4) 结论：基于系统评估以及弥漫性、预先存在的中层缺陷的一致存在，我们推测TAAD与升主动脉的发育缺陷有关，并且是由一种三重打击机制引起的，该机制涉及（I）内膜撕裂；以及（II）病变的中层，这使得（III）撕裂朝着滋养血管平面扩展，夹层在该平面进一步发展。
