Multicenter retrospective investigation into migration of fenestrated aortic stent grafts

Fenestrated stent grafts are subject to the same hemodynamic forces that have resulted in migration of standard infrarenal stent grafts. Outcome data for fenestrated endovascular aneurysm repair consist of short-term and midterm efficacy studies where migration was generally poorly investigated. This study investigated the migration of fenestrated stent grafts in patients treated by fenestrated endovascular aneurysm repair in the United Kingdom.

A total of 154 patients were retrospectively enrolled from nine sites across the United Kingdom. Patients had been treated with a Zenith fenestrated endograft (Cook Medical, Bloomington, Ind) between 2003 and 2010. Patients were required to have a baseline (first) postoperative computed tomography (CT) scan and at least one additional CT scan available. Measurements from the proximal stent graft to the superior mesenteric artery and from the distal stent graft to the iliac bifurcation were performed on the first postoperative CT scan. These measurements were repeated on all subsequent CT scans, and differences between the baseline and subsequent CT scans for the same anatomical location were suggestive of device migration. Migration was defined as cranial (-) or caudal (+) movement of the stent graft of ≥4 mm.

Proximal migration (median, +6.0 mm; range, +4.1 to +10.0 mm) was evident in 33 patients (21%). The probability of being free from proximal migration at 12, 24, and 36 months was estimated as 82% (95% confidence interval [CI], 75%-89%), 77% (95% CI, 70%-85%), and 77% (95% CI, 70%-85%), respectively. Of 259 limbs assessed, 34 (13%) showed evidence of cranial migration (median, -6.1 mm; range, -21.3 to -4.1 mm). The observed probability of being free from any iliac limb migration at 12, 24, and 36 months was 85% (95% CI, 79%-92%), 82% (95% CI, 75%-90%), and 65% (95% CI, 52%-80%), respectively.

Proximal migration occurs in approximately one-third of patients by 4 years, all migration was caudal in direction, with 60% <6.0 mm in length. Clinical sequelae were infrequent, with no statistically significant differences in the number of complications or reinterventions in patients with and without proximal migration.