Roach M R, Song S H
Department of Medical Biophysics, University of Western Ontario, London, Canada.
Clin Invest Med. 1994 Aug;17(4):308-18.
Dissecting aneurysms split the wall of the aorta and other large arteries to create a false lumen in parallel with the true lumen. Experiments were designed to determine the pressure required to tear the media and the work required per unit area to propagate the dissection once it started. India ink was injected into the media of 17 opened porcine aortas through a needle inserted parallel to the lumen of opened aortas placed in a saline bath. The ink was infused at 0.9 ml/min with a constant infusion pump as the pressure was monitored with a pressure transducer. The size of the bleb formed by the ink in the media was recorded with a video camera mounted perpendicular to the lumenal surface. All data were recorded on a computer. The pressure-volume curve was used to obtain the distensibility of the media (the upslope), the peak pressure, the tearing pressure, and the work of dissection (the area under the P-V curve once tearing occurred). The projected area of the bleb was calculated from the video images, and the work/area was calculated. The peak pressures were always extremely high, and ranged from 634 +/- 204 (SD) mmHg for the lower abdominal aorta to 816 +/- 145 mmHg for the lower thoracic aorta. The work/area ranged from 1.88 +/- 0.89 mJ/cm2 for the upper abdominal aorta to 11.34 +/- 4.05 mJ/cm2 for the lower abdominal aorta. An ANOVA showed that the lower abdominal aorta tore at lower pressures initially, but required much more energy to propagate the dissection. We believe that this is because of structural differences in the elastin pattern in the abdominal aorta.
夹层动脉瘤会使主动脉壁和其他大动脉壁分离，从而在真腔旁形成一个假腔。设计实验以确定撕裂中膜所需的压力以及一旦夹层开始扩展每单位面积所需的功。通过一根与置于盐水中的开放猪主动脉管腔平行插入的针，将印度墨水注入17个开放猪主动脉的中膜。在使用压力传感器监测压力的同时，用恒流泵以0.9 ml/分钟的速度注入墨水。用垂直于管腔表面安装的摄像机记录墨水中膜形成的气泡大小。所有数据都记录在计算机上。压力-容积曲线用于获得中膜的扩张性（上升斜率）、峰值压力、撕裂压力和夹层扩展功（撕裂发生后P-V曲线下的面积）。根据视频图像计算气泡的投影面积，并计算功/面积。峰值压力始终极高，范围从下腹部主动脉的634±204（标准差）mmHg到下胸部主动脉的816±145 mmHg。功/面积范围从上腹部主动脉的1.88±0.89 mJ/cm²到下腹部主动脉的11.34±4.05 mJ/cm²。方差分析表明，下腹部主动脉最初在较低压力下撕裂，但夹层扩展需要更多能量。我们认为这是由于腹主动脉弹性蛋白模式的结构差异。
