Print this pageAnatomic Three-Dimensional Analysis Of Enlarging Aneurysms Following Endovascular AAA Repair In the Gore Excluder Pivotal Clinical Trial
Mark Fillinger, for the Excluder Bifurcated Endoprosthesis Clinical Investigators
Dartmouth Hitchcock Medical Center, Lebanon, NH
INTRODUCTION AND OBJECTIVES:
Recent reports have raised concern about the percentage of enlarging AAAs after endovascular repair with the Gore Excluder device. To investigate this issue, a morphologic analysis was performed on enlarging aneurysms in the Excluder Pivotal clinical trial.
METHODS:
CT scans were obtained on all patients with at least 4 year follow-up and enlarging aneurysm by Core lab. CT scans were analyzed using 3-D reconstruction and 24 morphologic measurements.
RESULTS:
Thirty patients (30%) were identified with enlarging aneurysms at 4 years, providing data from 130 CT scans. Mean interval between scans was 10.6 months. By diameter criteria, 23% demonstrated interval growth from the prior scan, and 45% demonstrated growth relative to the initial scan. By 3-D volume (renal artery-aortic bifurcation), however, 56% demonstrated interval growth, and 80% demonstrated growth relative to the initial scan (p value <.0001 vs diameter). On average, enlargement was detected by volume 12.8 months before it was detected by diameter.
Only 20% of scans had apparent endoleak, but lack of delayed-contrast studies may underestimate the number of endoleaks. AAAs with endoleak demonstrated a greater interval rate of growth, however (4.5±4 vs 2.1±4 mm, p<.002). Although the etiology of enlargement may be endotension or device permeability in 80% of cases, other potential causes of aneurysm enlargement included: neck apposition length <15 mm (30%); large aortic diameter relative to device, (17%); large iliac diameter (13%); and iliac apposition length <15 mm (20%). There was no significant device migration, neck angulation, or device deformation. Multiple potential etiologies of enlargement were present in 50% of AAAs.
CONCLUSIONS:
The etiology of aneurysm enlargement in the Excluder pivotal trial is likely multifactorial, including endoleak, inadequate attachment length, and “endotension” or device permeability. Notably, 3-D volume criteria detected aneurysm enlargement more frequently and on average 1 year sooner than diameter criteria.