Chitosan-Sodium Tetradecyl Sulfate Hydrogel: Characterization and Preclinical Evaluation of a Novel Sclerosing Embolizing Agent for the Treatment of Endoleaks

Purpose: To compare the efficacy of an embolization agent with sclerosing properties (made of chitosan and sodium tetradecyl sulfate, CH-STS) with a similar embolization agent but without sclerosing properties (made of chitosan, CH) in treating endoleaks in a canine endovascular aneurysm repair model.

Methods: Two chitosan-based radiopaque hydrogels were prepared, one with STS and one without STS. Their rheological, injectability, and embolizing properties were assessed in vitro; afterwards, their efficacy in occluding endoleaks was compared in a canine bilateral aneurysm model reproducing type I endoleaks (n = 9 each). The primary endpoint was endoleak persistence at 3 or 6 months, assessed on a CT scan and macroscopic examination. Secondary endpoints were the occurrence of stent-graft (SG) thrombosis, the evolution of the aneurysm mean diameter, as well as aneurysm healing and inflammation scores in pathology examinations.

Results: In vitro experiments showed that both products gelled rapidly and presented initial storage moduli greater than 800 Pa, which increased with time. Both gels were compatible with microcatheter injection and occlude flow up to physiological pressure in vitro. In a type I endoleak model, the injection of CH-STS sclerosing gel tended to reduce the risk of occurrence of endoleaks, compared to CH non-sclerosing agent (2/9 vs. 6/9, p = 0.069). No case of SG thrombosis was observed. Moderate inflammation was found around both gels, with a comparable intensity score in both CH and CH-STS groups (2.6 ± 0.9 and 2.7 ± 0.9, respectively; p = 0.789).

Conclusions: Flow occlusion combined with chemical endothelial denudation appears promising for the treatment of endoleaks.

Level of evidence: N/A.

Chitosan; Embolization; Endoleak; Endovascular aneurysm repair; Hydrogels; Sclerosing agent.