Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China.
Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK.
Eur J Vasc Endovasc Surg. 2019 Sep;58(3):415-425. doi: 10.1016/j.ejvs.2019.02.026. Epub 2019 Jul 20.
Haemodynamic and geometric factors play pivotal roles in the propagation of acute type B aortic dissection (TBAD). The aim of this study was to evaluate the association between dissection level within all aortic layers and the propagation of acute TBAD in porcine aorta.
In twelve pigs, two models of TBAD were created. In model A (n = 6), the aortic wall tear was superficial and close to the intima (thin intimal flap), whereas in model B (n = 6) it was deep and close to the adventitia (thick intimal flap). Dissection propagation was evaluated using angiography or computed tomography scans, and the haemodynamic measurements were acquired using Doppler wires. Most pigs were followed up at 1, 3, 6, 12, 18, and up to 24 months; four animals were euthanised at three and six months, respectively (two from each group).
Both models were successfully created. No statistical difference was observed for the median antegrade propagation distance intra-operatively between the two models (p = .092). At 24 months, the longitudinal propagation distance was significantly greater in model B than in model A (p = .016). No statistical difference in retrograde propagation was noted (p = .691). Over time, aortic wall dissection progressed most notably over the first three months in model A, whereas it continued over the first 12 months in model B. Flow velocity was significantly greater in the true lumen than in false lumen at the level of the primary tear (p = .001) and in the middle of the dissection (p = .004). The histopathological images at three and six months demonstrated the fibres were stretched linearly at the outside wall of false lumen in both models, while the depth of intimal tears developed to be superficial and similar at the distal dissection.
In this swine model of TBAD, a deeper intimal tear resulted in greater dissection propagation.
血流动力学和几何因素在急性 B 型主动脉夹层（TBAD）的传播中起着关键作用。本研究旨在评估所有主动脉层内夹层水平与急性 TBAD 传播之间的关系。
在 12 头猪中，建立了两种 TBAD 模型。在模型 A（n=6）中，主动脉壁撕裂较浅且靠近内膜（薄内膜瓣），而在模型 B（n=6）中，撕裂较深且靠近外膜（厚内膜瓣）。使用血管造影或计算机断层扫描评估夹层传播，使用多普勒导丝获取血流动力学测量值。大多数猪在 1、3、6、12、18 个月时进行随访，最长随访至 24 个月；4 只动物分别在 3 个月和 6 个月时安乐死（每组 2 只）。
两种模型均成功建立。两种模型术中顺行传播距离的中位数无统计学差异（p=0.092）。24 个月时，模型 B 的纵向传播距离明显大于模型 A（p=0.016）。逆行传播无统计学差异（p=0.691）。随时间推移，模型 A 中主动脉壁夹层在最初的 3 个月内进展最为显著，而模型 B 中夹层则在最初的 12 个月内持续进展。在原发性撕裂处和夹层中部，真腔中的血流速度明显大于假腔（p=0.001 和 p=0.004）。在 3 个月和 6 个月的组织病理学图像中，两种模型的假腔外壁纤维均呈线性拉伸，而远端夹层的内膜撕裂深度变浅且相似。
在本猪 TBAD 模型中，较深的内膜撕裂导致更大的夹层传播。
