Malach Lillian, Tehrani Nader, Kolachina Shilpa, Krawczyk Karolina, Wozniak Amy, Soult Michael, Aulivola Bernadette, Bechara Carlos Fares
Stritch School of Medicine, Maywood, IL.
Vascular and endovascular surgery, Loyola Hospital, Maywood, IL.
Ann Vasc Surg. 2022 Feb;79:100-105. doi: 10.1016/j.avsg.2021.08.026. Epub 2021 Oct 14.
Aortic neck dilation post endovascular aneurysm repair (EVAR) has been implicated in the long-term development of endoleak and the subsequent re-intervention. Optimal endograft sizing is a vital aspect to successful repair. This study looked at percentage of graft oversizing as well as type of fixation on aortic neck dilation.
We retrospectively evaluated all EVARs completed at Loyola's University from 2006 to 2015 after IRB approval. Patients without follow-up scans within a year were excluded. We collected demographics, comorbidities, graft type, size, aortic neck diameter, maximum sac size diameters from the pre-operative and follow-up scans. We reviewed and collected data on 432 patients but analyzed 154. We measured the largest aortic diameter on axial images 1 cm above and 1 cm below the lowest renal artery. Change in supra and infrarenal aortic measurements were evaluated by calculating the mm difference from each scan compared to the pre-operative scan. Linear mixed effects models were used to estimate patients' mean differences over time.
We compared three groups of neck fixation grafts. Those with active suprarenal fixation had a significant change in suprarenal aortic diameter at four-year follow-up (1.86 mm, CI:0.65-3.06), compared to those with active infrarenal (0.22 mm, CI: -0.67 to -1.11) or passive suprarenal fixation (1.52 mm, CI: -0.11 to -3.15) (Fig. 1). Those with active suprarenal fixation were the only ones to have significant increase in suprarenal aortic diameter (P = 0.0026). Degree of oversizing was also divided into three groups. Oversizing by <10% had less impact on the suprarenal aorta than >15% oversizing at 4 years (0.41 mm, CI: -0.31 to -1.14 vs. 3.26 mm, CI: 1.63-4.88, P < 0.001) (Fig. 2). Oversizing had a more pronounced effect on the infrarenal aorta: 3.01 mm, CI: 2.18-3.83; 5.95 mm, CI: 3.26-8.64; and 5.05 mm, CI: 3.41-6.69 for <10%, 10-15%, and >15% oversizing at four years, respectively.
Stent-grafts with active fixation below the renal arteries as well as oversizing by <10% seem to have the least effect on aortic neck dilation over time. These factors should be considered when performing EVARs, as aortic neck dilation could lead to endoleak and need for further intervention. Further research defining the optimal stent-graft type, self-expanding versus balloon expandable, type of fixation and degree of oversizing.
血管内动脉瘤修复术（EVAR）后主动脉颈部扩张与内漏的长期发展及随后的再次干预有关。最佳的腔内移植物尺寸是成功修复的关键因素。本研究观察了移植物过大的百分比以及固定方式对主动脉颈部扩张的影响。
在获得机构审查委员会（IRB）批准后，我们回顾性评估了2006年至2015年在洛约拉大学完成的所有EVAR手术。排除一年内未进行随访扫描的患者。我们收集了患者的人口统计学资料、合并症、移植物类型、尺寸、术前及随访扫描的主动脉颈部直径、最大瘤囊直径。我们回顾并收集了432例患者的数据，但分析了其中154例。我们在最低肾动脉上方1 cm和下方1 cm的轴位图像上测量最大主动脉直径。通过计算每次扫描与术前扫描的毫米差值来评估肾上和肾下主动脉测量值的变化。使用线性混合效应模型估计患者随时间的平均差异。
我们比较了三组颈部固定移植物。在四年随访时，主动型肾上固定的患者肾上主动脉直径有显著变化（1.86 mm，CI：0.65 - 3.06），而主动型肾下固定（0.22 mm，CI： - 0.67至 - 1.11）或被动型肾上固定（1.52 mm，CI： - 0.11至 - 3.15）的患者则无显著变化（图1）。主动型肾上固定的患者是唯一肾上主动脉直径有显著增加的（P = 0.0026）。过大程度也分为三组。四年时，过大<10%对肾上主动脉的影响小于过大>15%（0.41 mm，CI： - 0.31至 - 1.14对比3.26 mm，CI：1.63 - 4.88，P < 0.001）（图2）。过大对肾下主动脉有更显著的影响：四年时，过大<10%、10 - 15%和>15%的患者肾下主动脉直径分别为3.01 mm，CI：2.18 - 3.83；5.95 mm，CI：3.26 - 8.64；和5.05 mm，CI：3.41 - 6.69。
肾动脉下方采用主动固定且过大<10%的覆膜支架似乎对主动脉颈部扩张的长期影响最小。进行EVAR手术时应考虑这些因素，因为主动脉颈部扩张可能导致内漏并需要进一步干预。需要进一步研究确定最佳的覆膜支架类型，即自膨式与球囊扩张式、固定方式以及过大程度。
