Intervention for unruptured high-grade intracranial dural arteriovenous fistulas: a multicenter study
Authors: Chen Ching-Jen , Buell Thomas J. , Ding Dale , Guniganti Ridhima , Kansagra Akash P. , Lanzino Giuseppe , Giordan Enrico , Kim Louis J. , Levitt Michael R. , Abecassis Isaac Josh , Bulters Diederik , Durnford Andrew , Fox W. Christopher , Polifka Adam J. , Gross Bradley A. , Hayakawa Minako , Derdeyn Colin P. , Samaniego Edgar A. , Amin-Hanjani Sepideh , Alaraj Ali , Kwasnicki Amanda , van Dijk J. Marc C. , Potgieser Adriaan R. E. , Starke Robert M. , Sur Samir , Satomi Junichiro , Tada Yoshiteru , Abla Adib A. , Winkler Ethan A. , Du Rose , Lai Pui Man Rosalind , Zipfel Gregory J. , Sheehan Jason P. , _ _ , _ _ , Zipfel Gregory J. , Kansagra Akash P. , Guniganti Ridhima , Piccirillo Jay F. , Raman Hari , Lipsey Kim , Lanzino Giuseppe , Giordan Enrico , Brinjikji Waleed , Vine Roanna , Cloft Harry J. , Kallmes David F. , Pollock Bruce E. , Link Michael J. , Sheehan Jason , Chen Ching-Jen , Patibandla Mohana Rao , Ding Dale , Buell Thomas , Paisan Gabriella , Kim Louis J. , Levitt Michael R. , Abecassis Isaac Josh , Meyer R. Michael , Kelly Cory , Bulters Diederik , Durnford Andrew , Duffill Jonathan , Ditchfield Adam , Millar John , Macdonald Jason , Fox W. Christopher , Polifka Adam J. , Laurent Dimitri , Hoh Brian , Smith Jessica , Lockerman Ashley , Gross Bradley A. , Lunsford L. Dade , Jankowitz Brian T. , Hayakawa Minako , Derdeyn Colin P. , Samaniego Edgar A. , Gutierrez Santiago Ortega , Hasan David , Roa Jorge A. , Rossen James , Guerrero Waldo , McGruder Allen , Amin-Hanjani Sepideh , Alaraj Ali , Kwasnicki Amanda , Charbel Fady T. , Aletich Victor A. , Rose-Finnell Linda , van Dijk J. Marc C. , Potgieser Adriaan R. E. , Starke Robert M. , Peterson Eric C. , Yavagal Dileep R. , Sur Samir , Chen Stephanie H. , Satomi Junichiro , Tada Yoshiteru , Kanematsu Yasuhisa , Yamamoto Nobuaki , Kinouchi Tomoya , Korai Masaaki , Yamaguchi Izumi , Yamamoto Yuki , Abla Adib , Winkler Ethan , Phelps Ryan R. L. , Lawton Michael , Rutkowski Martin , Du Rose , Lai Pui Man Rosalind , Aziz-Sultan M. Ali , Patel Nirav , Frerichs Kai U. 
Published: September 2021

OBJECTIVE
The risk-to-benefit profile of treating an unruptured high-grade dural arteriovenous fistula (dAVF) is not clearly defined. The aim of this multicenter retrospective cohort study was to compare the outcomes of different interventions with observation for unruptured high-grade dAVFs.

METHODS
The authors retrospectively reviewed dAVF patients from 12 institutions participating in the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR). Patients with unruptured high-grade (Borden type II or III) dAVFs were included and categorized into four groups (observation, embolization, surgery, and stereotactic radiosurgery [SRS]) based on the initial management. The primary outcome was defined as the modified Rankin Scale (mRS) score at final follow-up. Secondary outcomes were good outcome (mRS scores 0–2) at final follow-up, symptomatic improvement, all-cause mortality, and dAVF obliteration. The outcomes of each intervention group were compared against those of the observation group as a reference, with adjustment for differences in baseline characteristics.

RESULTS
The study included 415 dAVF patients, accounting for 29, 324, 43, and 19 in the observation, embolization, surgery, and SRS groups, respectively. The mean radiological and clinical follow-up durations were 21 and 25 months, respectively. Functional outcomes were similar for embolization, surgery, and SRS compared with observation. With observation as a reference, obliteration rates were higher after embolization (adjusted OR [aOR] 7.147, p = 0.010) and surgery (aOR 33.803, p < 0.001) and all-cause mortality was lower after embolization (imputed, aOR 0.171, p = 0.040). Hemorrhage rates per 1000 patient-years were 101 for observation versus 9, 22, and 0 for embolization (p = 0.022), surgery (p = 0.245), and SRS (p = 0.077), respectively. Nonhemorrhagic neurological deficit rates were similar between each intervention group versus observation.

CONCLUSIONS
Embolization and surgery for unruptured high-grade dAVFs afforded a greater likelihood of obliteration than did observation. Embolization also reduced the risk of death and dAVF-associated hemorrhage compared with conservative management over a modest follow-up period. These findings support embolization as the first-line treatment of choice for appropriately selected unruptured Borden type II and III dAVFs.