The protective status of subtotal obliteration of arteriovenous malformations after radiosurgery: significance and risk of hemorrhage.
OBJECTIVE
Arteriovenous malformations (AVMs) treated by radiosurgery with complete obliteration of the nidus but a persisting early draining vein on follow-up angiography can be termed subtotally obliterated. However, these are persistent circulating AVMs. The significance of these lesions, their hemorrhage rate, and their management are analyzed.


METHODS
In a series of 862 consecutive patients with AVMs treated by radiosurgery, 121 patients (14%) achieved subtotal obliteration (STO). The angiographic evolution and rate of obliteration were studied. The pretreatment angiographic features, dosimetric parameters, and postradiosurgery hemorrhage rate were compared with those in the rest of the treated population. Finally, the options for follow-up and treatment were analyzed.


RESULTS
Of 121 subtotally obliterated AVMs, the bleeding rate was 0%; 53% of patients achieved complete obliteration. This occurred in 71% of those who had STO at 1 year. In the cases in which STO was detected at 2, 3, and 4 years, total obliteration eventually occurred in 43%, 28.5%, and 0%, respectively. Comparative analysis with AVMs in which a part of the nidus persisted showed a significant difference in the bleeding rate. Except for volume, no significant statistical difference in angiographic and dosimetric parameters was found between the STO group and the rest of the studied population with residual nidus. Six cases received further treatment, resulting in 2 cures and 2 treatment-related complications.


CONCLUSIONS
Subtotally obliterated AVMs are different from other partially obliterated AVMs, with a 0% bleeding rate. Their complete obliteration is a function of delay of appearance on follow-up angiography. Invasive follow-up and further treatment of these AVMs do not seem warranted.
Abu-Salma
Zuair
Z
Department of Neurosurgery, Centre Hospitalier Sainte-Anne, Paris, France.
Nataf
François
F
Ghossoub
May
M
Schlienger
Michel
M
Meder
Jean-François
JF
Houdart
Emmanuel
E
Roux
François-Xavier
FX
D000293:Adolescent; D000328:Adult; D000368:Aged; D002533:Cerebral Angiography / Q000592:standards; D002536:Cerebral Arteries / Q000002:abnormalities / Q000503:physiopathology / Q000601:surgery; D002543:Cerebral Hemorrhage / Q000453:epidemiology* / Q000503:physiopathology / Q000517:prevention & control; D002550:Cerebral Veins / Q000002:abnormalities / Q000503:physiopathology / Q000601:surgery; D002648:Child; D015897:Comorbidity; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000453:epidemiology* / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019106:Postoperative Hemorrhage / Q000453:epidemiology* / Q000503:physiopathology / Q000517:prevention & control; D011829:Radiation Dosage; D016634:Radiosurgery / Q000706:statistics & numerical data*; D011880:Radiotherapy Planning, Computer-Assisted; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult