Key PointsQuestion
Is sirolimus an effective adjuvant therapy for endovascular embolization of extracranial head and neck arteriovenous malformations?
Findings
In this case series, all 6 patients with extracranial head and neck arteriovenous malformations had a favorable response to concurrent treatment with sirolimus and endovascular embolization. The combination therapy is also well tolerated for up to 3 years.
Meaning
The findings of this report suggest that the combination of sirolimus and embolization is clinically beneficial for patients with recurrent or complex, unresectable extracranial head and neck arteriovenous malformations and warrants further prospective study.
Importance
Current therapeutic options for patients with extracranial head and neck arteriovenous malformations are limited. Surgical intervention, such as sclerotherapy or resection, often result in rapid recurrence and progression of disease.
Objective
To assess the efficacy and tolerability of sirolimus as an adjuvant therapy for endovascular embolization in the management of complicated extracranial head and neck arteriovenous malformations.
Design, Setting, and Participants
This case series examined 6 patients with extracranial head and neck arteriovenous malformations treated from January 1, 2013, to December 31, 2017, at a multidisciplinary vascular anomalies clinic within Stanford Hospital and Clinics.
Intervention
Initiation of sirolimus at least 1 month prior to endovascular embolization, targeting a trough level of 10 to 15 ng/mL throughout the course of the endovascular embolization series and continued for at least 1 month after the series.
Main Outcomes and Measures
Clinical manifestations; disease progression and overall response to treatment were assessed via clinical evaluation and radiographic imaging.
Results
All 6 patients (4 male and 2 female patients; mean age, 24.5 years [range, 9-44 years]) responded favorably to the combination of sirolimus therapy followed by endovascular embolization, and 4 patients exhibited a near-complete response. The median duration of follow-up was 19 months (range, 6-40 months). One patient discontinued sirolimus soon after embolization and experienced regrowth of the arteriovenous malformation after 1 year. Sirolimus was resumed, which has stabilized his disease for more than 2 years. Mild adverse effects were noted in 4 patients. The combination therapy was well tolerated in all patients. One patient developed skin ulceration after embolization and required surgical debridement. Another patient developed pulmonary microthrombi after embolization with cyanoacrylate glue that resolved with a brief course of anti-inflammatory therapy.
Conclusions and Relevance
Although further prospective trials are needed, this report suggests the benefit of a mammalian target of rapamycin inhibitor as an adjuvant therapy for surgical embolization of complex, extracranial head and neck arteriovenous malformations. The optimal dosing and therapeutic duration of sirolimus treatment before and after embolization remain to be determined.