Bioresorbable Poly (L-Lactic Acid) Flow Diverter Versus Cobalt-Chromium Flow Diverter: In Vitro and In Vivo Analysis.

Abstract

BACKGROUND:

Permanent metallic flow diverter (FD) implantation for treatment of intracranial aneurysms requires antiplatelet therapy for an unclear duration and restricts postprocedural endovascular access. Bioresorbable FDs are being developed as a solution to these issues, but the biological reactions and phenomena induced by bioresorbable FDs have not been compared with those of metallic FDs.

METHODS:

We have developed a bioresorbable poly (L-lactic acid) FD (PLLA-FD) and compared it with an FD composed of cobalt-chromium and platinum-tungsten (CoCr-FD). FD mechanical performance and in vitro degradation of the PLLA-FD were evaluated. For in vivo testing in a rabbit aneurysm model, FDs were implanted at the aneurysm site and the abdominal aorta in the PLLA-FD group (n=21) and CoCr-FD group (n=15). Aneurysm occlusion rate, branch patency, and thrombus formation within the FD were evaluated at 3, 6, and 12 months. Local inflammation and neointima structure were also evaluated.

RESULTS:

Mean strut, porosity, and pore density for the PLLA-FD were 41.7 μm, 60%, and 20 pores per mm2, respectively. The proportion of aneurysms exhibiting a neck remnant or complete occlusion did not significantly differ between the groups; however, the complete occlusion rate was significantly higher in the PLLA-FD group (48% versus 13%; P=0.0399). Branch occlusion and thrombus formation within the FD were not observed in either group. In the PLLA-FD group, CD68 immunoreactivity was significantly higher, but neointimal thickness decreased over time and did not significantly differ from that of the CoCr-FD at 12 months. Collagen fibers significantly predominated over elastic fibers in the neointima in the PLLA-FD group. The opposite was observed in the CoCr-FD group.

CONCLUSIONS:

The PLLA-FD was as effective as the CoCr-FD in this study and is feasible for aneurysm treatment. No morphological or pathological problems were observed with PLLA-FD over a 1-year period.

• Authors: Natsuhi Sasaki, Akira Ishii, Shinichi Yagi, Hidehisa Nishi, Ryo Akiyama, Masakazu Okawa, Yu Abekura, Hirofumi Tsuji, Shinichi Sakurai, Susumu Miyamoto
• Journal: Stroke (Stroke) Vol. 54 Issue 6 Pg. 1627-1635 (06 2023) ISSN: 1524-4628 [Electronic] United States
• PMID: 37139818 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Chromium
• Cobalt
• Lactic Acid

Topics

• Animals
• Rabbits
• Absorbable Implants
• Chromium
• Cobalt
• Neointima
• Intracranial Aneurysm (diagnostic imaging, surgery)
• Vascular Diseases
• Lactic Acid
• Stents
• Treatment Outcome
• Endovascular Procedures