Stroke: Vascular and Interventional Neurology (Nov 2021)
Abstract 1122‐000236: Intravascular Delivery and Crosslinking of Photosensitive Hydrogels for Embolizing Animal Models of AVMs and Tumors
Abstract
Introduction: Embolization represents a minimally invasive treatment modality for arteriovenous malformations (AVMs), tumors, and other indications, but can be limited by currently available embolic agents, in terms of safety and efficacy. Discovery of new and improved agents could lead to better treatment outcomes. The goal of this project was to test a novel embolization methodology for the treatment of AVMs and tumors. Methods: We formulated low‐viscosity, shear‐thinning hydrogel formulations which were mixed with a photo‐initator agent and non‐ionic contrast medium. We then developed a method of intravascular hydrogel delivery with photo crosslinking at the tip of the catheter, using an integrated optical fibre. This allowed for rapid transition from a low viscosity liquid to a crosslinked solid‐state hydrogel to block blood flow to the vascular target. In addition, the UV intensity can be dynamically modulated, in real‐time, to modify the degree of crosslinking and thus the viscosity of the embolic agent. We utilized the swine rete mirabile as an animal model for AVMs, and the swine renal arterial tree (inferior segmental artery) as a model for hypervascular tumors. 5 animals were utilized without prior preparation. Embolization was graded based on degree of complete obliteration of the rete nidus or the renal arterial tree. Any non‐target embolization or other complications were recorded. Follow‐up angiography was performed at the 4‐week interval. Results: With a combination of shear‐thinning properties and dynamic modulation of photo crosslinking, we show that we are able to deliver an embolic agent with a viscosity range of up to 10^4 Pa*s through a single low viscosity precursor that is injectable through microcatheters (Figure 1). Using this methodology, hydrogel embolization was technically successful in all animals. Following embolization, 4/5 rete mirabile and 5/5 inferior renal arterial trees were completely obliterated. Representative angiographic images are shown in Figures 2 and 3. There were no instances of clinical or angiographic complications. Conclusions: We demonstrated a novel method of intravascular delivery of low viscosity photosensitive hydrogels, with photo crosslinking at the tip of the catheter, to successfully embolize animal models for AVMs and tumors. This promising technology will be investigated further with longer‐term comparative animal trials.
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