Morphological Study After Endovascular Abdominal Aortic Aneurysm

Objective:To review the diameter change in Abdominal Aortic Aneurysm(AAA), aneurysm neck diameter change and device migration after endovascular repair (EVR)of AAA and analyze the factors related to these changes.Methods:The completely preoperative CT of forty-five patients with AAAs who underwent EVR and followed up longer than 6 months at regular intervals were reviewed retrospectively.The follow-up program was contrast-enhanced CT at 1, 3,6,12 months and annually thereafter.The diameter change in AAA,aneurysm neck diameter change and device migration were reviewed respectively,and 5mm, 2mm,5mm were defined as a significant change correspondingly.No changes was defined as less than 5mm and 2mm.The patient-related and stent-graft-related factors were analyzed.The status of endoleak was detected by CT.Results:The average follow-up interval was 34.5±24.8 months(range, 9～100mon).(1)Aneurysm sac diameter changed from 51.9±9.7mm(range,30～82mm) preoperatively to 47.9±13.2mm(26.2～78.8mm)postoperatively(P＜.05).The mean diameter change was -4.0±8.3mm(-23.8～11mm).The expansion of sac diameter was detected in 15.6%and 4.5%when over-5mm and over-10mm respectively.The decrease of sac diameter was detected in 40%when more than 5mm.The sac diameter had kept stable was detected in 44.5%.There were 20 patients with endoleak intraoperation.Eight of these were type-1 endoleaks and twelve were type-2 endoleaks.The incidence of over-5mm decrease was 37.6%, 53.4%and 89.7%at 24,31 and 96months postoperatively respectively. (2)The mean proximal neck diameter was 21.5±2.3mm,22.44±2.36mm and 24.0±2.82mm at the preoperative,one month after operative and the latest follow-up.The increase of proximal neck diameter was detected in 71.1%.The oversizing percentage(OP)was 18.9±6.10%.The incidence of proximal neck over-sizing stent-graft in diameter was detected in 6.7%.The incidence of no dilation at proximal neck diameter was 97.4%,68.6%,39.3%and 3.3%(2 cases) at 16,24,36 and 96 months postoperatively respectively.(3)The stent-graft migration was detected in 22%,and was 7.0±1.32mm in average(range,0～9.5mm).There were not cases which the migration oversized 10mm,and no reintervine was necessary.The incidence of no migration was 87.5%,64.2%,32.1%and 16%at 28,66,82 and 96 months postoperatively respectively.Conclusions:(1)The intra-procedure endoleak has not significant effect on the change of AAA diameter.The persistent typeⅡendoleak,late and recurrent typeⅠendoleak may influence the expansion of AAA positively.(2)The more oversizing percentage,the more dilation the proximal neck.(3)The stent-graft migration and the dilation the proximal neck of median and long term follow-up might have effect on each other.(4)The suprarenal aortic stent-grafts might have decrease the frequency of migration...