Superselective methohexital challenge prior to intracranial endovascular embolization

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, 3-mg-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.

Intraoperative Neuromonitoring for Cerebral Arteriovenous Malformation Embolization: A Propensity-Score Matched Retrospective Database Study

Introduction The treatment of cerebral arteriovenous malformations (AVMs) may result in neurologic morbidity, particularly when an AVM is located in or adjacent to eloquent brain regions. Intraoperative neurophysiologic monitoring (IONM) may be utilized to reduce the risk of iatrogenic injury during endovascular AVM embolization; however, IONM for endovascular AVM embolization is not ubiquitously the standard of care. Methods Admissions for AVM embolization were assessed from the IBM MarketScan® Commercial and Medicare Supplemental databases (IBM Watson Health, Somers, NY). Inclusion criterion for patients was continuous enrollment six months before and after the index encounter. The use of IONM and presence of intracranial hemorrhage (ICH) were noted. Propensity-score matched cohorts with and without IONM were generated to minimize bias between treatment groups (adjusting for age, sex, and comorbidities). Results From 2007 to 2016, there were 16,279 patients diagnosed with cerebral AVM in the MarketScan database. Embolized patients were stratified into IONM and non-IONM cohorts; there were 357 patients in the IONM cohort and 1775 patients in the non-IONM cohort. Provider types were significantly different between cohorts (p<0.005). Unruptured AVMs were significantly more likely to be embolized with adjunctive IONM (17.7%) compared to ruptured AVMs (7.9%) (p<0.005). After balancing for baseline comorbidities, there were 266 patients in the IONM cohort, and 1347 patients in the non-IONM cohort. Among unruptured AVM patients, IONM was linked to a significantly shorter length of stay (2.72 versus 4.92 days; p<0.005), significantly lower rates of complications within 30 days of discharge (0.00% versus 1.88%; p=0.038), and significantly lower total payment ($40,179 versus $50,844; p<0.0001). Conclusion Endovascular embolization for unruptured AVMs performed with adjunctive IONM was associated with shorter length of stay, lower complication rates, and hospitalization costs.