Several different bioabsorbable polymeric coil materials are currently used with the goal of improving treatment outcomes of endovascular embolization of intracranial aneurysms. However, little is known about the correlation between polymer degradation profiles and concomitant tissue responses in a blood vessel. The authors describe in vitro degradation characteristics of nine different polymeric materials and their corresponding tissue responses induced in rabbit carotid arteries. Mass loss and molecular weight loss of nine commercially available bioabsorbable sutures were evaluated in vitro up to16 weeks. The same nine materials, as well as platinum coils, were implanted into blind-end carotid arteries (n = 44) in rabbits, and their tissue reactions were evaluated histologically 14 days after the implantation. Five of the nine polymers elicited moderate to strong tissue reactions relative to the remaining materials. While polymer mass loss did not correlate with their histologic findings, polymers that showed a faster rate of molecular weight loss had a tendency to present more active tissue reactions such as strong fibrocellular response around the implanted material with a moderate inflammatory cell infiltration. Maxon exhibited the fastest rate of molecular weight loss and poly-l-lactic acid the slowest. The rate of molecular weight loss may be an important factor that is associated with the degree of bioactivity when bioabsorbable polymers are implanted into blood vessels. For further quantitative analysis, additional experiments utilizing established aneurysm models need to be conducted.

BACKGROUND: Intracranial atherosclerotic disease (ICAD) significantly contributes to ischemic stroke, especially among Asian populations. Large vessel occlusion (LVO) due to underlying ICAD accounts for 15-35% of acute ischemic stroke cases requiring endovascular therapy. However, the successful recanalization rate of ICAD-related LVO remains lower. The TG dilator is a self-expandable device, temporarily dilating ICAD-related blocked blood vessels. OBJECTIVE: To demonstrate TG dilator safety and efficacy for ICAD-related acute ischemic stroke. METHODS: This was a single-arm, open-label, non-randomized, prospective, multicenter, and investigator-initiated trial that involved patients undergoing TG dilator application for acute ischemic stroke caused by ICAD-related LVO or severe stenosis. RESULTS: We enrolled 10 patients in this trial between November 2022 and April 2023. The median (IQR) age was 68 (59.3-75.3) years. Before using the dilator, seven patients received stent retriever treatment. All 10 patients were prescribed a loading dose of aspirin with prasugrel. The median application time was 10 (10-12) min. At the end of the procedure, we achieved significant recanalization immediately in all patients. The stenosis/occlusion decreased from 100% (100-100) to 68% (56.3-75.3). No patient experienced recurrent ischemic stroke or reocclusion within 90 days. We achieved a modified Rankin scale score of 0-2 in 8 patients by day 90. We detected no cases of intracranial hemorrhage, equipment failure, distal embolism, vasospasm, dissection, or perforation requiring intervention. CONCLUSIONS: Acute revascularization using the TG dilator on patients with ICAD-related LVO or severe stenosis did not cause any significant adverse event, and consistently improved blood flow at 90 days.