Left cerebral hemisphere hydrophilic polymer embolism associated with endovascular WEB treatment of a ruptured aneurysm of the anterior cerebral artery

Hydrophilic polymer embolism (HPE) is a rare, likely under-recognized iatrogenic complication, caused by fragmentation of surface materials used on endovascular medical devices. The organs most often involved in HPE are the brain and lungs, resulting in both local and systemic reactions. We present the case of a cerebral HPE associated with WEB treatment of a ruptured aneurysm of the anterior cerebral artery, and involving diffusely the left cerebral hemisphere. The patient developed pneumonia and status epilepticus, and died 24 days after the endovascular procedure, most likely as a result of the sequelae of the aneurysm rupture. The precise role of HPE in the sequence of events leading to death can remain, as in this case, a matter for speculation. However, the potential role of HPE in the events leading to death following diagnostic and therapeutic procedures should be appropriately assessed, especially when recovery does not progress as expected.