Study in JVS Defines Outcome-Based Anatomic Criteria for Hostile Aortic Necks

May 22, 2015—An analysis of the anatomic criteria most predictive of success or failure at the aortic neck after endovascular aneurysm repair (EVAR) was published by William D. Jordan Jr., MD, et al in the Journal of Vascular Surgery (2015;61:1383–1390). The background of the study is that while evidence links hostile proximal aortic neck anatomy to poor outcome after EVAR, the definition of hostile anatomy can vary between studies.

As summarized in the Journal of Vascular Surgery, the investigators examined data from 221 patients in the Aneurysm Treatment Using the Heli-FX Aortic Securement System Global Registry (ANCHOR) clinical trial. This population included patients with challenging aortic neck anatomy and failure of sealing. Failure at the aortic neck was defined by type Ia endoleak at endograft implantation or follow-up. The investigators assessed the value of anatomic measures in the classification of aortic neck success and failure, worked to identify optimal thresholds of discrimination, and created a final model with significant predictors of EVAR outcome.

Factors determined to be predictive of endoleak were increased aortic neck diameter at the lowest renal artery (P = .013) and at 5 mm (P = .008), 10 mm (P = .008), and 15 mm (P = .010) distally, aneurysm sac diameter (P = .001), common iliac artery diameters (right, P = .012; left, P = .032), and a conical neck configuration (P = .049). Binary logistic regression identified that neck diameter at the lowest renal artery (P = .002; cutpoint, 26 mm) and neck length (P = .017; cutpoint, 17 mm) were associated with endoleak.

Factors that were protective against endoleak were increased aortic neck length (P = .050), a funnel-shaped aortic neck (P = .036), and neck mural thrombus content, as measured by average thickness (P = .044) or degrees of circumferential coverage (P = .029). Binary logistic regression identified that some mural neck thrombus content was protective (P = .001; cutpoint, 11° of circumferential coverage).

Anatomic measures with identifiable threshold cutpoints should be considered when defining the hostile aortic neck and assessing the risk of complications after EVAR, concluded the investigators in the Journal of Vascular Surgery.