Schurink G W, Aarts N J, Wilde J, van Baalen J M, Chuter T A, Schultze Kool L J, van Bockel J H
Department of Surgery, Leiden University Medical Center, The Netherlands.
J Vasc Surg. 1998 Aug;28(2):234-41. doi: 10.1016/s0741-5214(98)70159-4.
Endoleakage is a fairly common problem after endovascular repair of abdominal aortic aneurysm and may prevent successful exclusion of the aneurysm. The consequences of endoleakage in terms of pressure in the aneurysmal sac are not exactly known. Moreover, the diagnosis of endoleakage is a problem because visualization of endoleaks can be difficult.
With an ex vivo model of circulation with an artificial aneurysm managed by means of a tube graft, studies were performed to evaluate precisely known diameters of endoleaks with both imaging techniques (computed tomography and digital subtraction angiography) and pressure measurements of the aneurysmal sac. The experiments were performed without endoleak (controls) and with 1.231-French (0.410 mm), 3-French (1 mm), and 7-French (2.33 mm) endoleaks. Pressure and imaging were evaluated in the absence and presence of a simulated open lumbar artery. The pressure in the prosthesis and in the aneurysmal sac were recorded simultaneously. Digital subtraction angiography with and without a Lucite acrylic plate, computed tomographic angiography, and delayed computed tomographic angiography were performed. For the first experiments, the aneurysmal sac was filled with starch solution. All tests were repeated with fresh thrombus in the aneurysmal sac.
Each endoleak was associated with a diastolic pressure in the aneurysmal sac that was identical to diastolic systemic pressure, although the pressure curve was damped. At digital subtraction angiography without a Lucite acrylic plate, the 1.231-French (0.410 mm) endoleak was visualized without an open lumbar artery. When a Lucite acrylic plate was added, the endoleak was not visible until a lumbar artery was opened. In the presence of thrombus within the aneurysmal sac, all endoleaks were not visualized at digital subtraction angiography. At computed tomographic angiography, all endoleaks were not visualized in the absence of a thrombus mass in the aneurysmal sac. In the presence of thrombus within the aneurysmal sac, the 1.231-French (0.410 mm) endoleak became visible after opening of a simulated lumbar artery. At delayed computed tomographic angiography, all endoleaks were visualized without and with thrombus.
Every endoleak, even a very small one, caused pressure greater than systemic diastolic pressure within the aneurysmal sac. However, small endoleaks were not visualized with digital subtraction angiography and computed tomographic angiography, whereas all endoleaks were visualized with a delayed computed tomographic angiography protocol. We believe that follow-up examinations after stent graft placement for aortic aneurysms should focus on pressure measurements, but until this is clinically feasible, delayed computed tomographic angiography should be performed.
内漏是腹主动脉瘤血管腔内修复术后相当常见的问题，可能会妨碍成功排除动脉瘤。内漏对瘤腔内压力的影响尚不完全清楚。此外，内漏的诊断也是一个问题，因为内漏的可视化可能很困难。
利用带有人造动脉瘤的体外循环模型，通过管状移植物进行管理，采用成像技术（计算机断层扫描和数字减影血管造影）和瘤腔压力测量来精确评估已知直径的内漏。实验在无内漏（对照组）以及有1.231法式（0.410毫米）、3法式（1毫米）和7法式（2.33毫米）内漏的情况下进行。在模拟开放腰动脉存在和不存在的情况下评估压力和成像。同时记录假体和瘤腔内的压力。进行有无有机玻璃丙烯酸板的数字减影血管造影、计算机断层血管造影和延迟计算机断层血管造影。对于首次实验，瘤腔内填充淀粉溶液。所有测试在瘤腔内有新鲜血栓的情况下重复进行。
尽管压力曲线有衰减，但每个内漏都与瘤腔内的舒张压相关，该舒张压与体循环舒张压相同。在没有有机玻璃丙烯酸板的数字减影血管造影中，1.231法式（0.410毫米）的内漏在没有开放腰动脉的情况下可见。当添加有机玻璃丙烯酸板时，直到开放腰动脉内漏才可见。在瘤腔内有血栓的情况下，数字减影血管造影中所有内漏均不可见。在计算机断层血管造影中，瘤腔内没有血栓块时所有内漏均不可见。在瘤腔内有血栓的情况下，模拟腰动脉开放后1.231法式（0.410毫米）的内漏可见。在延迟计算机断层血管造影中，有无血栓时所有内漏均可见。
每个内漏，即使非常小，都会导致瘤腔内压力高于体循环舒张压。然而，数字减影血管造影和计算机断层血管造影无法显示小的内漏，而延迟计算机断层血管造影方案能显示所有内漏。我们认为，主动脉瘤支架植入术后的随访检查应侧重于压力测量，但在临床上可行之前，应进行延迟计算机断层血管造影。
