Introduction Intra-aneurysmal flow is influenced by the curvature of the parent artery. Stent placement may straighten parent vessels with an impact in local hemodynamics. Few data have been reported about vascular geometry modification with the use of flow-diverter stents (FDS). The purpose of this study was to evaluate the geometry changes due to FDs placement in distal arteries and to compare nitinol and cobalt-chromium FDs angle modifications.

Methods We included patients treated with FDS for distal aneurysm between January 2012 and January 2018. Angles at the level of the neck have been measured on pre- and post-operative DSA in working projections. Angles measurement was performed at the intersection of 2 lines drawn from the neck center in the axis of the proximal and distal segments of the parent artery (figure 1). Angles variation was quantified with a rectification coefficient (R coeff)=(beta-alpha)/beta with alpha and beta respectively angles before and after FDS placement.

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Abstract E-021 Figure 1

Example of angles variation measurement for a previously coiled reanalized anterior communicating artery aneurysm treated with a cobalt-chromium FDs. Angles were measured at the intersection of 2 lines drawn from the neck center in the axis of the proximal and distal segments of the parent artery. Angles variation was quantified with the Rectification coefficient

Results 38 patients have been included. 5 (13%) received a nitinol FDS and 33 (87%) a cobalt-chromium FDS. The mean pre-operative and post-operative angles were respectively 107,2° and 133,6° (p<0.001). The R coeff was significantly different between nitinol and cobalt-chromium FDS with a greater variation observed with cobalt-chromium FDS (p=0.014). DSA follow-up showed 25 patients (86,2%) in cobalt-chromium group and 2 patients (40%) in nitinol group with complete aneurysm occlusion (p=0.018).

Conclusion FDs placement for distal aneurysms modulates vascular anatomy and might influence flow modifications and occlusion rates. This appears to be more important with cobalt-chromium than with nitinol FDS.

Disclosures K. Janot: None. V. Espindola: None. S. Saleme: None. A. El Ghanam: None. L. Mattos: None. C. Mounayer: None. A. Rouchaud: None.