Hydrophilic polymer embolic complication during diagnostic cerebral angiography presenting with delayed intracranial hemorrhage: case report and literature review.

We report two serial neuroendovascular cases of hydrophilic polymer embolic complications, and highlight a unique case of a routine diagnostic cerebral angiogram that was complicated by delayed intracranial hemorrhage requiring surgical decompression. Histopathology specimens revealed organized intravascular thrombi with foci of non-polarizable, basophilic foreign material. Shavings from the hydrophilic coatings of a standard diagnostic catheter and guidewire share histologic characteristics with this intravascular foreign material, confirming the diagnosis of hydrophilic polymer emboli. While this phenomenon has been described for complex neurointerventional procedures, it is rare with routine diagnostic cerebral angiography. Along with a detailed literature review, these cases provides further evidence that even basic hydrophilic coated catheters and/or wires may contribute to the etiology of iatrogenic emboli in the neurovasculature with the potential for acute and subacute complications, requiring further investigation.