Anatomic eligibility for endovascular aneurysm repair preserved over 2 years of surveillance.

Objective: Endovascular aneurysm repair (EVAR) is a widely used option for patients with suitable vascular anatomy who have a large infrarenal abdominal aortic aneurysm (AAA). Patients with small AAAs are managed with careful surveillance and it is a common concern that their anatomy may change with AAA growth, and their option for EVAR may become limited. Device innovation has resulted in expanded ranges of anatomy that may be eligible for EVAR. This study sought to identify changes in anatomic eligibility for repair with contemporary endovascular devices in AAA patients, monitored by computed tomography scan over the course of 2 years.

Methods: Patients from the Non-Invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TACT, NCT01756833) were included in this analysis. Females had baseline AAA maximum transverse diameter between 3.5 and 4.5 cm, and males had baseline maximum transverse diameter between 3.5 and 5.0 cm. Patients were included in this analysis if they completed pre-enrollment and 2-year follow-up computed tomography imaging. Pertinent anatomic measurements were performed on a postprocessing workstation in a centralized imaging core laboratory. EVAR candidacy was determined by measuring proximal aortic neck diameter, AAA length, and infrarenal neck angulation. Patients were considered to be eligible for EVAR if they qualified for at least one of the seven studied devices' instructions for use at baseline and at 2 years. A paired t test analysis was used to detect differences in aortic measurements over 2 years, and the McNemar test was used to compare eligibility over 2 years.

Results: We included 192 patients in this analysis-168 male and 24 female. Of these patients, 85% were eligible for EVAR at baseline and 85% after 2 years of follow-up (P = 1.00; 95% confidence interval -0.034 to 0.034). Of the 164 EVAR candidates at baseline, 160 (98%) remained eligible over 2 years of surveillance. Insufficient neck length was the most common reason for both ineligibility at baseline (18 of 28 patients) as well as loss of candidacy over 2 years (3 of 4 patients).

Conclusions: The majority of patients eligible for EVAR when entering a surveillance program for small AAA remain eligible after 2 years. Substantial changes in AAA neck anatomy resulting in loss of EVAR treatment options are infrequent. Patients with anatomic AAA progression beyond EVAR eligibility remain candidates for complex EVAR and open repair.