Bailout Technique for Coil Unraveling with a KUSABI Exchange Catheter: A Case Report

OBJECTIVE: Coil unraveling is a rare, yet dangerous complication of endovascular coiling. In this study, we report a patient in whom an intraoperatively unraveled coil was successfully retrieved using a KUSABI exchange catheter, which is used in the field of cardiovascular medicine to facilitate catheter exchange in coronary interventions. CASE PRESENTATION: The patient was a 90-year-old woman. To treat an unruptured aneurysm of the right internal carotid artery, endovascular coil embolization was performed. During the filling step, the coil started to unravel. Early attempts to retrieve the unraveled coil using a microsnare were complicated when the ensnared part broke off during the process. The broken tip of the unraveled coil was maneuvered inside the guiding catheter, after which a KUSABI catheter was inflated inside the guiding catheter to press and immobilize the unraveled coil against its inner lumen. This fragment of the unraveled coil was extricated from the patient by retracting the entire guiding catheter assembly. We guided a microsnare along the remaining unraveled coil to capture the intact part of the coil, and eventually retrieval was successful. CONCLUSION: To our knowledge, no study has reported retrieval with a KUSABI trapping balloon catheter for the management of coil unraveling. However, this method is considered effective. We report this case and review the literature.