Importance of graft configuration in outcome of endoluminal aortic aneurysm repair: a 5-year analysis by the life table method.

AIM: The aim of this study was to determine the influence of graft configuration on the outcome of endoluminal repair of abdominal aortic aneurysm (AAA).

METHODS: The 5-year study period extended from May 1992 to May 1997 and included analysis of patients undergoing endoluminal AAA repair in the first 4.5-year period with a minimum follow-up period of 6 months. Between May 1992 and November 1996 136 patients underwent endoluminal AAA repair. Two patients who had endoluminal repair of anastomotic AAA and six patients who had secondary endoluminal repair of AAA were excluded, leaving 128 patients in the study group. There were 117 males and 11 females with a mean age for the group of 71 years. The configuration of the grafts was tubular aortic (T) (n = 50), tapered aortoiliac/femoral (AI) (n = 24) and bifurcated (B) (n = 54). Patient characteristics and co-morbidities were similar in the three groups. The procedures were performed in the operating room under radiographic control. Follow-up was complete and consisted of regular physical examination and contrast enhanced computed tomography. Outcome measures were perioperative mortality rate, need for conversion to open repair, presence of early and late endoleaks, successful exclusion of AAA from the circulation, and survival. Data were analysed by the life table method.

RESULTS: There was no significant difference in perioperative mortality for T (4%), AI (4%) and B (5.5%) configuration of endograft. Outcome for T, AI, and B configurations was respectively: primary conversion (%) 8, 12, 13; early endoleaks (n =) 5, 0, 1; late endoleaks (n =) 7, 0, 1. The overall incidence of failed procedures throughout the study period was higher in tube grafts compared with non-tube (aortoiliac and bifurcated) grafts (p < 0.05). Kaplan-Meier curves demonstrated a success probability at 40 months of 50% for tube grafts and 80% for non-tube grafts. However, a comparison of the time to procedure failure between tube versus non-tube after adjusting for competing risks (death without prior graft failure) was non-significant (p = 0.14).

CONCLUSIONS: The poor mid-term outcome for tube prostheses requires a reassessment of the criteria for selecting this configuration. It would be unwise to abandon the use of tube prostheses entirely in endoluminal repair. With increasing information on mid and long-term outcome of endoluminal AAA repair it is likely that there will be an increasing acceptance of treating smaller AAA while they are still suitable for treatment by the endoluminal method and most likely with tube grafts. A tightening of the criteria for using tube prostheses would seem sensible. In particular, the minimum length of distal neck required for endoluminal tube graft repair should be increased to the 2-2.5 cm range.