Long-term outcomes of Palmaz stent placement for intraoperative type Ia endoleak during endovascular aneurysm repair.

BACKGROUND: Perioperative proximal endoleaks during endovascular aneurysm repair potentiate graft migration, aneurysm sac expansion, and stent-graft failure. Adjunctive placement of a Palmaz stent at the proximal landing zone can improve proximal seal and eliminate perigraft flow; however, the long-term sequelae associated with this maneuver are unknown. We sought to evaluate the effect of Palmaz stent placement for type Ia endoleaks on delayed endoleak formation, graft migration, and aneurysm expansion.

METHODS: A retrospective cohort review of a prospectively maintained database was performed. Between 2000 and 2005, all consecutive patients who had undergone infrarenal endovascular aneurysm repair were evaluated for a type I endoleak that was treated with Palmaz stent placement. Fenestrated, juxtarenal, and investigational devices were excluded from the analysis. Postoperative and follow-up axial imaging were analyzed for the following three primary endpoints: type I endoleak formation, stent-graft migration, and aneurysm sac expansion. In addition, a paired analysis was performed comparing suprarenal aortic diameters, infrarenal aortic neck diameters, aortic neck lengths, and proximal seal zones.

RESULTS: In all, 36 consecutive patients were identified with intraoperative type I endoleaks that were treated with Palmaz stenting. Five patients with ruptured abdominal aortic aneurysms died before discharge; the remaining 31 patients comprised the cohort for analysis. During a median follow-up period of 53 months (interquartile range: 14-91 months), no type I endoleak developed after Palmaz stent placement. Despite patients experiencing shortening of aortic neck length (26%) and loss of the proximal seal zone (35%), no stent-graft migration was seen in this population. Continued aortic degeneration accounted for proximal seal zone loss. At a distance 15 mm below the lowest renal artery, the mean aortic diameter increased by 3.2 mm (95% confidence interval: 0.4-6, p < 0.5), and 63% of patients demonstrated an increase of >10%. Mean aortic sac regression was 5.8 mm (95% confidence interval: 0.5-11.0, p < 0.05). Overall, at the final follow-up evaluation, aortic sac regression was found to have occurred in 55% of patients, aortic sac increased up to 10% in 20% of the patients, and by more than 10% in 25% of the patients.

CONCLUSIONS: Proximal neck reinforcement with a Palmaz stent serves as an effective endovascular adjunct to treat intraoperative type I endoleaks, and has a very high technical success rate. Most importantly, it has a clinical effect on delayed type I endoleak formation and stent-graft migration.