Tam A S, Sapp M C, Roach M R
Department of Medical Biophysics, University of Western Ontario, London, Canada.
J Biomech. 1998 Jul;31(7):673-6. doi: 10.1016/s0021-9290(98)00058-x.
An in vitro model was used to determine the influence of tear depth on the propagation pressure of aortic dissections. Saline was injected into the media of segments of 20 porcine thoracic aortas to create blebs. A circumferential slit was made on the intimal side of each bleb, connecting the true lumen to the false lumen. Each aorta was then pressurized under no-flow conditions until propagation in either the anterograde or retrograde direction occurred. Histological sections of each principal propagating edge were used to determine depth of tear, measured as the ratio of elastin layers in the intimal flap to the elastin layers in the intact wall. Propagation occurred for tear depths ranging from 0.44 to 0.89, with dissections closest to the adventitia (with tear depths near 1) requiring the lowest pressures. Propagation pressure (P) depends on the number of elastin layers (L) in the outer wall of a dissection, P = 0.44 L + 25(kPa), r2 = 0.465, p = 0.003 and also on tear depth (d): P = -58 d + 81(kPa), r2 = 0.547, p < 0.001. Various in vivo factors are discussed which may affect these experimentally determined relationships.
采用体外模型来确定泪液深度对主动脉夹层扩展压力的影响。将盐水注入20个猪胸主动脉段的中膜以形成水疱。在每个水疱的内膜侧制作一个圆周切口，将真腔与假腔相连。然后在无血流条件下对每个主动脉进行加压，直到出现顺行或逆行扩展。使用每个主要扩展边缘的组织学切片来确定泪液深度，以内膜瓣中的弹性蛋白层数与完整壁中的弹性蛋白层数之比来衡量。泪液深度在0.44至0.89范围内时会发生扩展，最靠近外膜的夹层（泪液深度接近1）所需压力最低。扩展压力（P）取决于夹层外壁中的弹性蛋白层数（L），P = 0.44L + 25（kPa），r2 = 0.465，p = 0.003，并且还取决于泪液深度（d）：P = -58d + 81（kPa），r2 = 0.547，p < 0.001。讨论了可能影响这些实验确定关系的各种体内因素。
