Asystole During Onyx Embolization of a Pediatric Arteriovenous Malformation: A Severe Case of the Trigeminocardiac Reflex

Background: Trigeminal-cardiac reflex (TCR) from the stimulation of sensory branches of trigeminal nerve can lead to hemodynamic instability. This phenomenon has been described during ophthalmologic, craniofacial, and skull base surgeries. TCR has been reported rarely with endovascular onyx embolization of dural arteriovenous fistulas.

Case description: We report a case of TCR during endovascular Onyx embolization of an arteriovenous malformation (AVM). A 16-year-old boy presented with a large cerebellar AVM with arterial feeders from the external carotid artery and posterior cerebral artery branches. The middle meningeal artery was catheterized, through which dimethyl sulfoxide was injected, followed by Onyx, into the nidus and the feeders. Near the completion of embolization, patient became bradycardic and proceeded to asystole; he was resuscitated with chest compression, atropine, and vasopressors. We used PubMed to identify the reported cases of Onyx and other endovascular embolizations complicated by hemodynamic instability. We found 16 cases of endovascular onyx embolization complicated by clinically significant hemodynamic changes in the treatment of dural arteriovenous fistula, cavernous carotid fistula, and juvenile nasopharygeal angiofibroma but not with AVMs. In these cases, arterial supply to the nidus involved the sensory receptive field of trigeminal nerve. Hemodynamic changes have been reported during the injection of dimethyl sulfoxide before the introduction of Onyx, as well as Onyx injection and cast formation.

Conclusions: TCR can lead to significant hemodynamic changes during endovascular Onyx embolization of vascular malformations (both pial AVM and dural arteriovenous fistulas) involving receptive field of trigeminal nerve. Therefore, the anesthesiologist should be made aware of treatment approach before intervention and appropriate precautions taken.