Recurrence after cure in cranial dural arteriovenous fistulas: a collaborative effort by the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR)
Authors: Abecassis Isaac Josh , Meyer R. Michael , Levitt Michael R. , Sheehan Jason P. , Chen Ching-Jen , Gross Bradley A. , Smith Jessica , Fox W. Christopher , Giordan Enrico , Lanzino Giuseppe , Starke Robert M. , Sur Samir , Potgieser Adriaan R. E. , van Dijk J. Marc C. , Durnford Andrew , Bulters Diederik , Satomi Junichiro , Tada Yoshiteru , Kwasnicki Amanda , Amin-Hanjani Sepideh , Alaraj Ali , Samaniego Edgar A. , Hayakawa Minako , Derdeyn Colin P. , Winkler Ethan , Abla Adib , Lai Pui Man Rosalind , Du Rose , Guniganti Ridhima , Kansagra Akash P. , Zipfel Gregory J. , Kim Louis J. , _ _ , _ _ , 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
Cranial dural arteriovenous fistulas (dAVFs) are often treated with endovascular therapy, but occasionally a multimodality approach including surgery and/or radiosurgery is utilized. Recurrence after an initial angiographic cure has been reported, with estimated rates ranging from 2% to 14.3%, but few risk factors have been identified. The objective of this study was to identify risk factors associated with recurrence of dAVF after putative cure.

METHODS
The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) data were retrospectively reviewed. All patients with angiographic cure after treatment and subsequent angiographic follow-up were included. The primary outcome was recurrence, with risk factor analysis. Secondary outcomes included clinical outcomes, morbidity, and mortality associated with recurrence. Risk factor analysis was performed comparing the group of patients who experienced recurrence with those with durable cure (regardless of multiple recurrences). Time-to-event analysis was performed using all collective recurrence events (multiple per patients in some cases).

RESULTS
Of the 1077 patients included in the primary CONDOR data set, 457 met inclusion criteria. A total of 32 patients (7%) experienced 34 events of recurrence at a mean of 368.7 days (median 192 days). The recurrence rate was 4.5% overall. Kaplan-Meier analysis predicted long-term recurrence rates approaching 11% at 3 years. Grade III dAVFs treated with endovascular therapy were statistically significantly more likely to experience recurrence than those treated surgically (13.3% vs 0%, p = 0.0001). Tentorial location, cortical venous drainage, and deep cerebral venous drainage were all risk factors for recurrence. Endovascular intervention and radiosurgery were associated with recurrence. Six recurrences were symptomatic, including 2 with hemorrhage, 3 with nonhemorrhagic neurological deficit, and 1 with progressive flow-related symptoms (decreased vision).

CONCLUSIONS
Recurrence of dAVFs after putative cure can occur after endovascular treatment. Risk factors include tentorial location, cortical venous drainage, and deep cerebral drainage. Multimodality therapy can be used to achieve cure after recurrence. A delayed long-term angiographic evaluation (at least 1 year from cure) may be warranted, especially in cases with risk factors for recurrence.