Pharmacologic Provocative Testing in Combination With Intraoperative Neurophysiologic Monitoring During Arteriovenous Malformation Embolization

OBJECTIVE: To review our use of pharmacologic provocative testing (PT) and intraoperative neurophysiologic monitoring (IONM) during endovascular embolization for eloquent arteriovenous malformations (AVMs), and better define their clinical utility. -METHODS: This is a prospective study between 1 June 2018 and 1 June 2020. Prior to endovascular embolization, superselective PTs with propofol injection were performed. The PT results were assessed by IONM. The impact of different doses of propofol on PT results was compared. -RESULTS: Under general anesthesia, 111 PTs and 48 endovascular embolizations were performed in 22 patients. For the initial 48 PTs before planned embolization, 38 PTs with 5 mg propofol were negative and repeat PTs with 7 mg propofol were also negative. For the remaining 10 positive PTs, the microcatheter tip was adjusted to an alternative site until repeat PTs were negative to ensure a subsequent safe embolization. In comparison, 5-mg-propofol PT results were consistent with 7-mg-propofol PTs in larger-sized feeders, whereas for smaller-sized vessels, 3mg-propofol PT results were consistent with 5-mg-propofol PTs. The negative predictive value of PTs was 97.9% (47 of 48), as only 1 of the 48 embolizations with negative PTs resulted in postoperative hemorrhage and none of the other 47 embolizations led to a postoperative neurologic deficit. -CONCLUSIONS: PTs and IONM are valuable techniques to predict neurologic deficits and improve procedure decision-making during AVM embolization under general anesthesia. A 5-mg dose of propofol may be sufficient for PTs in larger-sized feeders and a 3-mg dose may be sufficient in smaller-sized feeding branches.