Long-Term Experimental Evaluation of In Situ Laser-Fenestrated Versus Custom-Made Fenestrated Endografts

Objective: This study evaluates the biomechanical performance and long-term durability of in situ laser fenestration (ISLF) compared to custom-made fenestrated endografts (CMD) using a controlled bench-top experimental setup. Methods: In situ, laser fenestration was performed in a RelayPro Dacron endograft using a 2.0 mm Turbo Elite OTW Laser Atherectomy catheter. Ten BeGraft Bridging Stent-Grafts (BSG) were implanted in 5 ISLF and 5 CMD Zenith fenestrations and subjected to 50 million fatigue cycles. Fenestrations were evaluated radiographically and microscopically for shape, size, fraying, endograft tearing, and BSG integrity. Results: Fenestration areas (median 8.1 mm 2 ) and axis lengths (median long axis: 4.03 mm, median short axis: 2.33 mm) in the ISLF group were significantly less than CMD fenestrations (median area: 24 mm 2 ; median long axis: 5.83 mm, median short axis: 5.8 mm) immediately post-manufacturing (p=0.002), but increased significantly after stenting and fatigue (p=0.002). Tearing was observed in 3 of 5 ISLF after ballooning but resolved after BSG implantation. BSG integrity was superior in the ISLF group, with no all-layer defects, while 3 of the 5 tested BeGrafts used in the CMD group revealed fabric defects with partial fracture of the stent in 2 (p=0.007). Conclusion: ISLF fenestrations demonstrated comparable durability to CMD fenestrations after long-term fatigue testing, with distinct advantages in BSG integrity preservation. These findings support ISLF as a viable option for urgent treatment, although further research is warranted to validate these results. Clinical Impact In-situ laser fenestration is a feasible technique for urgent complex aortic repair when customized or off-the-shelf devices are unavailable or technically unfeasible. However, long-term mechanical stability and durability under fatigue testing have not been previously evaluated. This study is the first to directly compare the long-term mechanical performance of industry-made custom fenestrations with in-situ laser fenestrations using a fatigue model. Results demonstrate non-inferiority of in-situ laser fenestrations, supporting their use as an effective off-label strategy for emergency or bailout interventions.