Preparation, characterization, and evaluation of radiopaque hydrogel filaments for endovascular embolization

Abstract

Radiopaque hydrogel filaments were prepared, characterized, and evaluated for potential use as implants for endovascular embolization of vascular defects. Three hydrogel formulations were prepared by free radical polymerization: (i) poly(ethylene glycol) diacrylate with 2,4,6-triiodophenyl penta-4-enoate (PEG-I), (ii) poly(ethylene glycol) diacrylamide with barium sulfate (PEG-B), and (iii) poly(propylene glycol) diacrylate with barium sulfate (PPG-B). The PEG-B and PPG-B hydrogels exhibited radiopacity comparable with clinically used platinum coils, whereas the PEG-I hydrogel did not. In the dry state, the average ultimate tensile strength and strain of the hydrogels ranged from 37 to 128 gf and 21% to 72%, respectively. The PEG-B hydrogel had significantly higher tensile strength compared with the PEG-I hydrogel. In the hydrated state, the average ultimate tensile strength and strain ranged from 5 to 15 gf and 7% to 30%, respectively. Statistically significant differences in tensile strength were not present when hydrated. Compared with poly(ethylene) after 4-week implantation into the subcutaneous space of rabbits, the PEG-I hydrogel elicited slightly more inflammation, whereas the PEG-B and PPG-B hydrogels elicited less inflammation. All three hydrogel formulations elicited less fibrous encapsulation than poly(ethylene). With further development, these materials have potential as embolization devices.

In Vitro and In Vivo Imaging Characteristics Assessment of Polymeric Coils Compared with Standard Platinum Coils for the Treatment of Intracranial Aneurysms

“…These studies have shown promising results in detecting aneurysmal remnants after treatment with hydrogel filaments and demonstrate the potential of CTA to provide images suitable to determine whether re-treatment is necessary. [17][18][19] The present study, through the use of different imaging modalities, has demonstrated that polymeric coils cause less imaging artifacts compared with standard platinum coils on all imaging modalities. Overall, they provided better imaging and visualiza- tion of the coil mass, coil details, and the soft tissue area adjacent to the embolized aneurysm.…”

“…To date, only limited data about polymeric-based embolization material for endovascular treatment of cerebral aneurysms are available in the literature. [17][18][19] The purpose of this study was to evaluate the imaging characteristics and artifact production of a polymeric coil system for the treatment of intracranial aneurysms compared with standard platinum coils.…”

Angiographic and artefact-free computed tomography imaging of experimental aneurysms embolised with hydrogel filaments

“…Detailed descriptions of the preparation, characterisation and physical evaluation of the hydrogel filaments are given elsewhere [15]. Briefly, the iodine-containing filament comprised 60% w/w triiodophenylpenta-4-enoate, 20% w/w acrylic acid and 19% w/w poly(ethylene glycol).…”

“…One approach towards the development of embolic devices compatible with CTA uses metal-free hydrogel filaments [15]. We have prepared such detachable embolic devices using cylindrical pieces of hydrogel that possess a secondary helical shape and a defined length.…”

Use of CT Angiography in Comparison with Other Imaging Techniques for the Determination of Embolus and Remnant Size in Experimental Aneurysms Embolized with Hydrogel Filaments

“…17 Briefly, the hydrogel filaments comprised 66% barium sulfate, 23% trimethylolpropane ethoxylate triacrylate, 8% tert-butyl acrylate, 2% 2-hydroxyethyl methacrylate, and 1% N,NЈ-methylenebisacrylamide. Filaments of various secondary diameters (2-6 mm and straight) and lengths (4 -20 cm) were used to embolize the aneurysm sac.…”