No major difference in outcomes for endovascular aneurysm repair stent grafts placed outside of instructions for use

Objective: Studies have shown that a sizable percentage of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAAs) is performed outside the instructions for use (IFU). We report our long-term outcomes after EVAR with respect to device-specific IFU. Methods: Computed tomography angiography data from a cohort of 566 patients meeting inclusion criteria who underwent elective EVAR between 2003 and 2014 were examined. Preoperative anatomic measurements for each patient were taken and compared with device-specific IFU. Primary outcomes included all-cause mortality and AAA-related mortality. Secondary outcomes were late-onset rupture, need for reintervention, endoleaks, aneurysm sac enlargement, and intraoperative and perioperative complications. Results: Nine different stent grafts were placed in this set of patients with a mean follow-up of 3.54 +/- 2.65 years. Most patients (465; 82.2%) were male, and the mean age was 74.8 +/- 8.70 years. Overall, 176 patients (31.1%) fit all IFU anatomic criteria, and 535 patients (94.5%) fit at least half of IFU criteria. In patients, iliac artery diameter was most commonly outside of IFU (253; 44.7%). A total of 1114 iliac arteries were treated, with 463 (41.6%) treated outside of iliac artery diameter IFU; the majority of these (374; 80.7%) were larger than IFU. Demographics and comorbidities were comparable between the groups within and outside of IFU. AAA-related mortality and all-cause mortality were similar between these two groups, as was late-onset rupture, need for reintervention, rates of endoleak, aneurysm sac enlargement, and major intraoperative and perioperative complications. The sole statistically significant difference in secondary outcomes was increased perioperative blood transfusion needed in those treated outside the IFU, 13.2% vs 6.2% in those treated within IFU (P=.02); however, this was not associated with decreased access vessel diameter or iliac artery rupture. Conclusions: Despite most EVAR patients being treated outside of IFU, there was no difference in outcomes with respect to all-cause mortality or aneurysm-related mortality. In addition, with the exception of perioperative blood transfusions, there was no association between IFU adherence and late-onset rupture, need for reintervention, rates of endoleak, aneurysm sac enlargement, or most other major complications.