Matsumura J S, Chaikof E L
Department of Surgery, Northwestern University Medical School, Chicago, Ill, USA.
J Vasc Surg. 1998 Sep;28(3):422-30; discussion 430-1. doi: 10.1016/s0741-5214(98)70127-2.
Longitudinal studies have revealed that the aortic segment proximal to an infrarenal abdominal aortic aneurysm (AAA) is at risk for continued enlargement after a standard aneurysm repair. Similarly, preliminary reports have shown expansion of one or both aortic necks after endovascular repair. Although some investigators have suggested that this may be a transient effect, continued dilatation at the endograft attachment site could effect the overall device stability.
As part of a multi-institutional trial of endovascular grafting for the treatment of AAA, 59 patients were successfully implanted with straight endografts between February 1993 and January 1995. A morphometric analysis of aortic neck size was undertaken with serial review of computed tomography scans available through April 1997. The neck sizes at both graft attachment sites were measured, with investigators blinded to patient identity and date of scan. Changes in minor diameter were defined, annual interval expansion rates were calculated, and the data were correlated with endoleak, device migration, aneurysm size change, endograft diameter, attachment system fractures, and initial preimplant neck size.
Significant aortic neck enlargement, particularly at the level of the distal neck, was observed for at least 24 months after AAA repair. The annual interval dilation rates of the proximal aortic neck were 0.7 +/- 2.1 mm/year (P = .023) and 0.9 +/- 1.9 (P = .008) mm/year during the first and second years, respectively. Enlargement of the distal neck during the observation period was more marked, with corresponding annual expansion rates of 1.7 +/- 2.9 mm/year (P < .001) and 1.9 +/- 2.5 (P < .001) mm/year. In 5 patients (14%), the minor diameter of the distal neck was at least 6 mm larger than the preimplant diameter of the graft. Migration of the distal attachment system was observed in 3 of these 5 patients. Expansion rates did not have a statistically significant correlation with initial neck size, endograft dimensions, aneurysm size change, presence of endoleak, or attachment system fracture.
Aortic neck enlargement was observed for at least 2 years after endovascular grafting. Close patient follow-up remains mandatory in lieu of the potential risk of late failure as a result of continued aortic expansion. The relative contribution of device design to this phenomenon will need to be defined.
纵向研究表明，在标准动脉瘤修复术后，肾下腹主动脉瘤（AAA）近端的主动脉段仍有继续扩大的风险。同样，初步报告显示，血管腔内修复术后一个或两个主动脉颈部会扩张。尽管一些研究人员认为这可能是一种短暂效应，但移植物附着部位的持续扩张可能会影响整个装置的稳定性。
作为一项多机构血管腔内移植物治疗AAA试验的一部分，1993年2月至1995年1月期间，59例患者成功植入了直管型移植物。通过对1997年4月前可获得的计算机断层扫描进行系列回顾，对主动脉颈部尺寸进行形态计量分析。测量移植物两个附着部位的颈部尺寸，研究人员对患者身份和扫描日期不知情。定义小直径的变化，计算年度间隔扩张率，并将数据与内漏、装置移位、动脉瘤大小变化、移植物直径、附着系统骨折以及植入前初始颈部尺寸相关联。
AAA修复术后至少24个月观察到主动脉颈部显著扩大，尤其是在远端颈部水平。近端主动脉颈部在第一年和第二年的年度间隔扩张率分别为0.7±2.1mm/年（P = 0.023）和0.9±1.9（P = 0.008）mm/年。观察期内远端颈部的扩大更为明显，相应的年度扩张率分别为1.7±2.9mm/年（P < 0.001）和1.9±2.5（P < 0.001）mm/年。在5例患者（14%）中，远端颈部的小直径比植入前移植物直径至少大6mm。在这5例患者中有3例观察到远端附着系统移位。扩张率与初始颈部尺寸、移植物尺寸、动脉瘤大小变化、内漏的存在或附着系统骨折无统计学显著相关性。
血管腔内移植术后至少2年观察到主动脉颈部扩大。鉴于主动脉持续扩张导致晚期失败的潜在风险，密切随访患者仍然是必要的。需要确定装置设计对这一现象的相对影响。
