A prospective study of changes in aneurysm and graft length after endovascular exclusive of AAA using balloon and self-expanding endograft systems

Abstract

Purpose: Longitudinal shrinkage of aneurysms post-endovascular repair, employing unvalidated measurement techniques has been held to account for endograft disruption. In this study we record changes in aneurysm length, diameter and volume using the gold standard of calibrated spiral CT angiography (SCTA). Method: From 179 patients with AAA scanned by SCTA, 68 were selected for endografting. Twenty-seven had PTFE home-made prostheses while 41 patients had Talent endografts. SCTA was performed on the fifth postoperative day and 6-monthly intervals thereafter. The distance between the lowest renal artery and the aortic bifurcation (VBL-vertical body length) and the luminal centre line length (LCL) were measured. Maximal sac diameters and volumes were recorded using 3DCT reconstruction. Results: Significant increase was noted in VBL (3.2) mm for PTFE-treated patients accompanied by an increase in sac volume at day 5 (12.4 ml). No changes in LCL or maximal diameters were evident. At 1.5 years further lengthening of both VBL (6.4 mm) and LCL (9.3 mm) was unaccompanied by sac diameter/volume changes. Talent patients-no changes in VBL or LCL were evident. Volumes and maximal AP and transverse diameters showed marked shrinkage: AP-11.2 mm; transverse-2.6 mm; volumes by-35.5 ml at 6 months. Conclusion: With PTFE increase in VBL but not graft length, without concurrent changes in maximal diameters at day 5, is commensurate with increase in sac volume; after 1.5 years graft lengthening overtakes aortic lengthening. In Talent patients VBL/graft length remained unchanged. There is no evidence for longitudinal aneurysmal contracture. Volumes and maximal diameters for the Talent endograft but not for PTFE show shrinkage.