Respect, Don't Fear, the Short Proximal Aortic Neck: Analysis Of the BCVI AAA Ten-Year EVAR Experience

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Barry T. Katzen, MD, Alexandra A. MacLean, MD, James F. Benenati, MD, Gerald Zemel, MD, Alex Powell, MD, Shaun Samuels, MD, Howard E. Katzman, MD.
Baptist Cardiac and Vascular Institute, Miami, FL, USA.

Background:
Patients with short proximal aortic necks (< 15mm) do not meet the approved indications for endovascular aneurysm repair (EVAR) because of technical hurdles including proximal fixation and seal. Inadequate sealing can lead to a Type IA endoleak. We compared outcomes of 91 patients with short proximal aortic necks to those with ≥ 15mm necks.
Methods:
Between 1994 and 2004 we treated 584 AAA patients with EVAR. There were 400 patients with neck measurements from helical CT scans (3mm slices) used for this analysis. Devices used included: Ancure, AneuRx, Excluder, Talent, Trivascular, Vanguard, Zenith. The cohort was divided into 3 groups according to the length of the proximal aortic neck: Grp I. 5 to 9mm (41 patients), Grp II. 10 to 14mm (50 patients), and Grp. III. ≥ 15mm (309 patients). Primary endpoints were mortality, Type IA endoleak, conversion and delayed rupture rates. We also examined age, sex, survival (early and late), and renal function.
Results:
Mean age did not differ significantly. Mean proximal neck lengths lengths were: Grp I: 7mm, Grp II:11mm, and Grp III: 25mm. This analysis included Talent (n=166 via research protocol), Ancure (n=138), Excluder (n=39) AneuRx (n=21), Vanguard (n=20), Zenith (n=14) and Trivascular (n=2) endografts. The Talent and Zenith permit trans-renal fixation. The dominant device used was: Grp I. Talent (78%), Grp II. Talent (66%), and Grp. III. Ancure (39%) but the Ancure, AneuRx, and Excluder were also used successfully in all groups. Type IA endoleak rates varied among the groups: Grp I. 19.5%, Grp II. 2%, Grp. III. 4.2% (p= 0.0001). Group I was also statistically more likely (p=0.0001) to have both early and late Type IA endoleaks that were managed by balloon angioplasty, balloon expandable stents, and the use of additional sealing cuffs. A greater neck angulation did not contribute to an increased Type IA endoleak rate. There was no statistical difference in procedure success, post-procedure creatinine clearance, conversion to open surgery, delayed rupture rate, and overall survival.
Conclusions:
Type IA endoleak rate is significantly higher in the group with the shortest neck, however, it was managed almost entirely with endovascular techniques and did not affect the long term durability or comparative success of EVAR in the three groups of patients. Patients with proximal necks > 10 mm fared as well as those in the standard > 15 mm group. Endovascular repair of abdominal aortic aneurysms with proximal necks < 10 mm can be accomplished but may require additional procedures to acquire a proximal seal.