Mechanical Thrombectomy for N-butyl-2 Cyanoacrylate Cerebral Embolism via Portopulmonary Venous Anastomosis Following Endoscopic Injection Sclerotherapy: A Case Report

Cerebral embolism following endoscopic injection sclerotherapy using N-butyl-2 cyanoacrylate for esophagogastric varices is a rare but serious complication. This condition occurs due to the migration of N-butyl-2 cyanoacrylate into the cerebral circulation, which has traditionally been attributed to paradoxical embolism via a patent foramen ovale. However, recent reports have suggested the possibility of alternative embolic pathways. We report the case of a 76-year-old woman who presented with acute gastric variceal bleeding and underwent endoscopic injection sclerotherapy using N-butyl-2 cyanoacrylate and Lipiodol. Shortly after the procedure, the patient developed global aphasia and right hemiparesis. Head computed tomography revealed scattered ultra-hyperdense materials and magnetic resonance imaging confirmed left middle cerebral artery M2 occlusion. Mechanical thrombectomy was performed, achieving successful recanalization and neurological improvement. Imaging findings and histopathological analysis of the retrieved thrombus strongly supported the diagnosis of N-butyl-2 cyanoacrylate embolism. Retrospective evaluation of preoperative contrast-enhanced computed tomography identified a portopulmonary venous anastomosis, a right-to-left shunt connecting gastric varices to the pulmonary veins. This anastomosis is a collateral pathway associated with portal hypertension. This case suggests that even in the absence of a patent foramen ovale, portopulmonary venous anastomosis can serve as a route for N-butyl-2 cyanoacrylate migration into the cerebral circulation. To the best of our knowledge, this is the first reported case of mechanical thrombectomy for N-butyl-2 cyanoacrylate cerebral embolism following endoscopic injection sclerotherapy. This case underscores the importance of early detection and risk assessment of such right-to-left shunting and highlights mechanical thrombectomy as a viable intervention for cases where thrombolysis is contraindicated.