Differing morphological changes following endovascular AAA repair using balloon-expandable or self-expanding endografts

Purpose: To determine whether changes in aneurysm morphology after endovasc ular abdominal aortic aneurysm (AAA) repair differ according to the type of endograft (self-expanding versus balloon-expandable). Methods: Among 88 patients with AAA treated with either homemade polytetraf luoroethylene (PTFE) aortomonoiliac endografts or Talent stent-grafts, 30 p atients (24 males; mean age 73 years, range 55-93) were selected for this s tudy based on a >2-year follow-up and freedom from endoleak or conversion. Of these, 12 had PTFE endografts and 18 Talent devices. All patients had sp iral computed tomographic angiography with 3-dimensional reconstruction at 5 days posttreatment and 6-month intervals thereafter. Neck dimensions (len gth and diameters at 3 levels) were measured, along with volumes and maxima l diameters of the sac and lengths of the aneurysm and endograft. Intra- an d interobserver errors were <5% for linear and volume measurements. Results: Both groups had an initial 20-mL increase in median volume (p = 0. 02) followed, only in Talent patients, by marked shrinkage at 6 months (-87 .4 mL; p = 0.09). PTFE patients had no further changes in sac volume. Maxim al sac diameters reflected volumes, but only after day 5. PTFE patients had an immediate increase (p = 0.03) in aneurysm neck diameters, which then re mained stable. Talent patients had continuing increases in diameter to 6 mo nths (p < 0.05), with no change thereafter. Length changes were not signifi cant in either group. PTFE patients had an increase in median aneurysm leng th at day 5 (+3.2 mm, p = 0.04) and again at 1.5 years (+6.4 mm, p = 0.03). Endograft length slowly increased (+18.7 mm) over 1.5 years (p = 0.02). Ta lent patients had no length changes in the device or aneurysm. Conclusions: Aneurysm morphology appeared to alter according to the type of endograft deployed. With PTFE endografts, aneurysm volume does not change, whereas impressive sac shrinkage occurs in conjunction with the Talent sys tem. Aneurysm/graft lengths increase with unsupported stent-grafts. Neck di ameter increases immediately with balloon-expandable endografts and then re mains constant. In the self-expanding models, neck diameter increases at 6 months but not thereafter.