The rabbit superior mesenteric artery as an in vivo model for perforator artery occlusion assessment after flow diversion.

OBJECTIVE

Covering side branches with flow diverters (FDs) raises concerns regarding side branch occlusion and potentially delayed ischemic complications. Existing preclinical models fail to replicate these risks. We developed a novel preclinical model using the rabbit superior mesenteric artery (SMA) to investigate FD-associated branch occlusion and neointimal changes.

MATERIAL AND

METHODS

Eighteen rabbits were enrolled; three were excluded for periprocedural complications. Fifteen animals completed follow-up, each with a single FD implanted in the SMA (one of three Pipeline Embolization Devices: 5 Bare-Flex, 4 Shield-Flex, and 6 Vantage). Branch patency (using Digital subtraction angiography DSA and histology) and ostial coverage/neointima (using optical coherence tomography OCT), were assessed at 1 or 3 months. Results were compared between-(FD and time) groups using Mann-Whitney and Kruskal-Wallis test.

RESULTS

Fifteen animals completed the study. Among 35 covered branches, 30 (85.7%) remained patent, 4 (11.4%) were pre-occlusive, and 1 (2.9%) occluded. Median ostium coverage by OCT was 77.0%. Mean in-stent stenosis was 35.0%. No significant difference were found across FD types or timepoints comparing patency, medium ostium coverage, in-stent stenosis. Histology confirmed progressive neointimal maturation and partial to full ostium coverage, with strong correlation to OCT findings. No correlation was found between neointimal thickness and ostium coverage.

CONCLUSION

The rabbit SMA model successfully detected rare occlusions and common pre-occlusive changes, approaching clinical data. This model may help to evaluate FD safety, optimize design, and investigate endothelial responses.