LAUSR

Conclusions: Aortic neck diameter increases consistently over time following EVAR. The degree of neck dilatation correlates with degree of device oversize but not with device type. Summary: Implications of aortic neck dilatation following endovascular aneurysm repair (EVAR) are unclear. Previous studies are limited to comparisons of individual, early generation devices. The authors’ compared aortic neck dilatation among contemporary stent grafts in this retrospective study of a prospectively maintained single center database. They reviewed preoperative and postoperative computed tomographic angiograms (at least one > 6 months after implant) for elective EVARs performed from 2008-2014. Images were analyzed using three-dimensional centerline reconstructions. Aortic neck diameter was measured in orthogonal planes at and 10mm below the lowest renal artery. Device type and main body graft diameter were obtained from operative reports. Eighty-six patients were analyzed with a median radiologic follow-up of 21.9 months (range, 4-64 months) and 81.3% had imaging at one year. The cohort was predominantly male (86.1%) with a mean age of 75.6 years (range, 60-94 years) and comorbidities were notable for significant coronary disease (50.0%) and smoking history (76.7%). Stent grants implanted included 26 Cook Zenith, 26 Gore Excluder, 22 Medtronic Endurant, 10 Endologix Powerlink, and 2 Trivascular Ovation devices. Mean device oversizing was 13.6 6 11.5% and did not vary by device type (P 1⁄4 .54). Most patients (86.0%) experienced increases in aortic neck diameter during follow-up, with a mean increase of 1.3 6 2.2 mm (5.9 6 9.3 %) and 3.3 6 0.6 mm (8.9 6 2.5%) at 30 day and at latest follow-up scans, respectively. Repeated-measures analysis further demonstrated a significant increase in mean neck dilatation during follow-up (P < .001). Neck dilatation was not significantly different across different devices (P 1⁄4 .233). However, there was a moderate positive correlation between percent change in neck diameter and degree of oversizing, which was statistically significant (P < .001). Type IA endoleak was observed in two patients and was associated with greater mean neck dilatation (8.8 6 3.3 mm vs 3.35 6 2.71; P 1⁄4 .041). There was no relationship between changes in neck diameter and sac regression/expansion. Comments: This study demonstrates infrarenal aortic neck dilation after endograft repair, which is progressive over time and associated with endograft oversizing. Whether this is due to the radial force the device uses to secure water tight seal, which then ceases when this force vector reaches equilibrium as some studies suggest, or to progressive aneurysmal growth is still not completely understood. The latter event would, of course, be unfortunate since a wave of type IA endoleaks would be expected that fortunately has not be observed in current experience. This study would confirm this lack of clinical consequence but lacks longterm follow-up. A similar focus was reported in the Journal of Vascular Surgery but at 24 months there was a negative clinical impact with a higher risk of type IA endoleaks observed at 24 months. Much is yet to be learned regarding endograft repair of infrarenal abdominal aortic aneurysms in the long-term that being 10-15 years. Reference 1. Gargiulo M, Gallitto E, Wattez H, Verzini F, Massoni GB, Loschi D, et al. Outcomes of endovascular aneurysm repair performed in abdominal aortic aneurysms with large infrarenal necks. J Vasc Surg 2017;66:1065e1072.