Effect of Aneurysm and Bicuspid Aortic Valve on Layer-Specific Ascending Aorta Mechanics
Effect of Aneurysm and Bicuspid Aortic Valve on Layer-Specific Ascending Aorta Mechanics
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DOI：
10.1016/j.athoracsur.2018.05.071
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发表时间：
2018-12-01
影响因子：
4.6
通讯作者：
Sokolis, Dimitrios P.
中科院分区：
文献类型：
--
作者：
Deveja, Rezar P.;Iliopoulos, Dimitrios C.;Sokolis, Dimitrios P.
背景。先前的研究尚未检验内膜层、内侧层和外膜层在为升胸主动脉瘤 (ATAA) 壁提供机械强度方面与非动脉瘤主动脉相比的参与情况。在本研究中，我们比较了 ATAA 和非动脉瘤主动脉完整壁及其各层的机械特性，并明确考虑了瓣膜形态的影响；即二尖瓣主动脉瓣 (BAV) 与三尖瓣主动脉瓣 (TAV) 和主动脉象限。方法。完整的 ATAA 取自接受选择性修复的患者，非动脉瘤主动脉则取自年龄匹配的尸检受试者。将它们切成 2 个圆周和纵向组织条，以获得完整的壁及其每个象限的层，从而可以将主动脉壁作为多层结构进行检查。对组织进行拉伸测试以确定失效特性。结果。非动脉瘤性和 BAV-ATAA 中的完整壁和层特异性失效拉伸（即延展性）显着大于 TAV-ATAA，这不受弹性蛋白/胶原含量变化的影响。 BAV-ATAA 中的完整壁破坏应力（即强度）明显大于 TAV-ATAA 中的，与内侧破坏应力类似。在大多数受试者组、层和完整壁中，失效应力和拉伸与年龄呈负相关，但失效拉伸与残余拉伸（即层之间的结构粘合）呈正相关。结论。没有发现 BAV-ATAA 的机械脆弱性，证实了当前有关二尖瓣主动脉病治疗的保守指南。患有瓣膜缺损、主动脉根部动脉瘤、高血压和高脂血症的患者的身体虚弱和脆弱性增加。在两类患者中，衰老导致解剖开始或完全破裂或两者兼而有之的可能性增加。 (C) 2018 年胸外科医师协会
Background. Previous studies have not examined the participation of intimal, medial, and adventitial layers in providing mechanical strength to the ascending thoracic aortic aneurysm (ATAA) wall compared with the nonaneurysmal aorta. In this study we compared the mechanical properties of intact wall and its layers among ATAAs and nonaneurysmal aortas, with explicit consideration of the effects of valve morphology; that is, bicuspid aortic valve (BAV) versus tricuspid aortic valve (TAV), and aortic quadrant.Methods. Whole ATAAs were taken from patients undergoing elective repair and nonaneurysmal aortas from age-matched autopsy subjects. These were cut into 2 circumferential and longitudinal tissue strips for the intact wall and its layers per quadrant, permitting examination of the aortic wall as a multilayered structure. Tissue underwent tensile testing for determination of failure properties.Results. Intact wall and layer-specific failure stretches (ie, extensibilities) were significantly greater in nonaneurysmal and BAV-ATAA than in TAV-ATAA, unaccounted for by elastin/collagen content changes. Intact wall failure stress (ie, strength) was significantly greater in BAV-ATAA than in TAV-ATAA, in analogy with medial failure stress. Failure stress and stretch associated negatively with age in most subject groups, layers, and intact wall, but failure stretch correlated positively with residual stretch (ie, structural bonds between layers).Conclusions. No mechanical vulnerability of BAV-ATAA was found, corroborating current conservative guidelines regarding the management of bicuspid aortopathy. Weakening and added vulnerability was found in patients with valvular deficiency, aortic root aneurysm, hypertension, and hyperlipidemia. Aging led to increased susceptibility to dissection initiation or full rupture, or both, in both patient classes. (C) 2018 by The Society of Thoracic Surgeons