Onyx Cast Migration to the Right Ventricle Following Trans-arterial Embolization of a Cranial Dural Arteriovenous...

We report a case of a middle-aged man who presented to the cardiology clinic with an incidental finding of a hyperdense lesion in the right ventricle (RV). He is an ex-smoker and had a low-dose CT chest as part of a screening program for early lung malignancy. His medical history included a cerebellar hemorrhage in 2021 due to a ruptured dural arteriovenous fistula (dAVF). He was treated as an emergency with trans-arterial embolization using Onyx liquid embolic material (Medtronic, Fridley, MN). The high-flow dAVF embolization was straightforward, with Onyx filling the arteriovenous (AV) shunt and draining the vein. The patient made a good recovery, and routine cerebral digital subtraction angiography (DSA) at three months confirmed the occlusion of the dAVF. Cardiac migration of liquid embolic material used to treat AV shunts is uncommon and probably underreported as it can be asymptomatic, as in this case. Cardiac embolization should be suspected in patients with dense material in the RV and prior treatment with trans-arterial embolization.