Embolization and endothelial ablation with chitosan and sodium sotradecol sulfate: preliminary results in an animal model.

PURPOSE: To investigate whether embolization with chitosan hydrogel (CH) with or without a sclerosant (sodium tetradecyl sulphate, STS) can induce chemical endothelial ablation and prevent endothelial recanalization in a rabbit model. METHODS: Chitosan radiopaque thermogels were prepared using chitosan, ß-glycerophosphate, iopamidol, and different STS concentrations. Each auricular artery of 14 New Zealand White rabbits was cannulated and injected with 0.6 mL of chitosan (CH0; n = 14) on one side and either saline (n = 3), chitosan and 1% STS (CH1; n = 6), or chitosan and 3% STS (CH3; n = 6) in the contralateral side. Immediately after embolization and at 1, 7, 14, and 30 days, auricular artery patency and percentage of recanalization were assessed by visual inspection; microcirculation was evaluated using laser Doppler imaging (LDI). The rabbits were sacrificed at 30 days to assess endothelial ablation and inflammatory response by histological analyses. RESULTS: All arteries were catheterized and embolized with success. All saline-injected arteries rapidly recovered normal flow. The length of embolization was greater with CH3 than CH1 or CH0, regardless of the time observed (p<0.001). No difference in recanalization length was found among the gels (p = 0.07). Destruction of arterial wall was frequently observed independent of embolizing agent. Foreign body reaction was more frequent with CH3 as compared with CH1 and CH0 (p = 0.0070 and 0.0058, respectively). After 30 days, hypervascularization was observed on LDI only with CH0; it was attributed to intra- or perivascular neovessels and inflammatory response on pathological analysis. The vascular modifications appeared to be more homogenous across the length of embolization with CH3 than the other formulations. CONCLUSION: The viscosity obtained with chitosan and 3% STS permits better control during injection and longer vascular occlusion. These findings, combined with the intravascular neovascularization observed with CH0, led us to prefer the combination with STS.