Heikkinen Maarit A, Alsac Jean Marc, Arko Frank R, Metsänoja Riina, Zvaigzne Agnis, Zarins Christopher K
Department of Surgery, University of Tampere, Tampere, Finland.
J Vasc Surg. 2006 Jun;43(6):1130-7; discussion 1137. doi: 10.1016/j.jvs.2006.01.031.
Secure proximal fixation of endografts to the infrarenal aortic neck is known to be important in the short- and long-term success of endovascular aneurysm repair. We sought to determine the relative importance of distal iliac fixation in preventing endograft migration and adverse clinical events after endovascular aneurysm repair.
We reviewed the outcome of 173 patients treated from 1996 to 2003 at Stanford University Medical Center with an externally supported stent graft. Quantitative image analysis of the postimplantation computed tomography scan was performed to determine the proximal aortic and distal iliac fixation lengths and the proximity the distal end of the stent graft to the iliac bifurcation. Subsequent follow-up computed tomography scans were reviewed for evidence of stent graft migration. Patients were grouped according to good (>15 mm), intermediate, or bad (<10 mm) aortic fixation and good (iliac fixation length > or =25 mm and iliac limbs <10 mm from iliac bifurcation), intermediate, or bad (<25-mm fixation length) iliac fixation.
Stent graft migration of 10 mm or more was seen in 17 patients (10%) during the 23 +/- 19-month follow-up period. Patients with no migration had a greater iliac fixation length (30 +/- 12 mm) than those with migration (22 +/- 8 mm; P = .01), and the distal ends of the iliac limbs were closer to the iliac bifurcation (15 +/- 12 mm) than in patients with migration (25 +/- 10 mm; P < .001). Patients with no migration also had a greater proximal aortic fixation length (23 +/- 12 mm) than migration patients (13 +/- 7 mm; P = .001). There were no migrations among patients with good iliac fixation whether aortic fixation was good, intermediate, or bad (0/63; 0%). Among patients with bad/intermediate iliac and good aortic fixation, there were 5 (9%) of 58 patients had migrations. Patients with both bad/intermediate iliac and bad/intermediate aortic fixation had the highest migration rate (12/52; 23%). Cox proportional hazards regression modeling revealed that the significant factors predicting migration were poor proximity of the distal end of the iliac limbs to the iliac bifurcation (odds ratio 17.2; P = .01) and aortic fixation length (odds ratio 2.0; p = 0.007 for each centimeter). Iliac extender modules were placed in 9 patients with bad iliac fixation and migration, with no further migration during a mean follow-up of 12 months. Patients with good iliac and aortic fixation and no endoleak on the initial postprocedure computed tomography scan (n = 43) had no migrations, secondary procedures, or adverse clinical events over a 2-year follow-up period.
Iliac fixation, along with proximal aortic fixation, is an important factor in preventing the migration of stent grafts that have longitudinal columnar support. Patients with good iliac fixation did not experience migration even in the presence of suboptimal proximal aortic fixation. Close proximity of the distal end of the stent graft to the iliac bifurcation seems to provide stability against migration.
腔内动脉瘤修复术的短期和长期成功，肾下主动脉颈部的近端内支架牢固固定很重要。我们试图确定远端髂动脉固定在防止腔内动脉瘤修复术后内支架移位和不良临床事件中的相对重要性。
我们回顾了1996年至2003年在斯坦福大学医学中心接受外部支撑支架移植物治疗的173例患者的结果。对植入后的计算机断层扫描进行定量图像分析，以确定近端主动脉和远端髂动脉的固定长度以及支架移植物远端与髂动脉分叉的距离。随后的随访计算机断层扫描被复查以寻找支架移植物移位的证据。患者根据良好（>15mm）、中等或不良（<10mm）的主动脉固定以及良好（髂动脉固定长度≥25mm且髂动脉分支距髂动脉分叉<10mm）、中等或不良（固定长度<25mm）的髂动脉固定进行分组。
在23±19个月的随访期内，17例患者（10%）出现了10mm或更大的支架移植物移位。无移位患者的髂动脉固定长度（30±12mm）大于有移位患者（22±8mm；P = 0.01），且髂动脉分支距髂动脉分叉的距离更近（15±12mm），而有移位患者为（25±10mm；P < 0.001）。无移位患者的近端主动脉固定长度（23±12mm）也大于有移位患者（13±7mm；P = 0.001）。髂动脉固定良好的患者中，无论主动脉固定是良好、中等还是不良，均无移位（0/63；0%）。在髂动脉固定不良/中等且主动脉固定良好的患者中，58例患者中有5例（9%）出现移位。髂动脉和主动脉固定均不良/中等的患者移位率最高（12/52；23%）。Cox比例风险回归模型显示，预测移位的显著因素是髂动脉分支距髂动脉分叉的距离不佳（比值比17.2；P = 0.01）和主动脉固定长度（每厘米比值比2.0；P = 0.007）。9例髂动脉固定不良且有移位的患者放置了髂动脉延长模块，在平均12个月的随访期间未再出现移位。术后初始计算机断层扫描显示髂动脉和主动脉固定良好且无内漏的患者（n = 43）在2年随访期内无移位、二次手术或不良临床事件。
髂动脉固定与近端主动脉固定一样，是防止具有纵向柱状支撑的支架移植物移位的重要因素。髂动脉固定良好的患者即使近端主动脉固定欠佳也未出现移位。支架移植物远端靠近髂动脉分叉似乎可提供抗移位稳定性。
