Late Outcomes of Thoracic Endovascular Aneurysm Repair Outside Versus Inside Instruction for Use

Objectives: To evaluate results of thoracic endovascular aortic repair (TEVAR) for thoracic aortic aneurysm (TAA) and to investigate outcomes based on adherence to manufacturer’s instructions for use (IFUs). Methods: Patients treated with TEVAR in 4 tertiary hospitals between 2010 and 2021 were collected. Patients with connective tissue disorders, post-dissection TAAs, aortic coarctation and intramural haematomas were excluded. Both elective and urgent procedures were considered. Primary outcome was long-term survival. Secondary outcomes were: aortic-related reinterventions and late TEVAR failure. Results: Out of 192 patients, 147 (76%) had endografts deployed inside IFU and 45 (24%) did not. Early outcomes were similar between groups with mortality rates of 6% inside IFU and 8.8% outside. Median follow-up was 36 months (interquartile range 20-63 months). Survival rate at 1, 3, and 5 years were 90%, 75%, and 61% for IFU group and 97%, 87%, and 66% for outside-IFU group (P = .55). Freedom from aortic-related reintervention at 1, 3, and 5 years were 94%, 87%, and 80% for IFU group and 88%, 78%, and 74% for outside IFU group (P = .04). TEVAR failure at 5 years occurred in 18 (13%) of inside IFU and 9 (22%) of outside IFU (P = .13). Conclusions: TEVAR is safe and effective in the long-term. Performing TEVAR outside IFU guidelines can still be acceptable but poses a higher risk of reintervention, especially for proximal landing zone violations. Close follow-up is essential to detect late failures.