Embolization as one modality in a combined strategy for the management of cerebral arteriovenous malformations

Abstract

We attempted to assess clinical results of management of cerebral arteriovenous malformation using a combination of endovascular, surgical and radiotherapeutic approaches. We retrospectively reviewed the angiographic and clinical data on prospectively collected consecutive patients treated by embolization from 1994 to 2004. The general philosophy was to attempt treatment by a combination of approaches only when an angiographic cure was likely or at least possible. The clinical outcome was assessed according to the modified Rankin scale. Although 404 patients were collected, complete files and follow-ups are available for 227 or 56% only. Most patients presented with hemorrhages (53%) or seizures (23%). The final management consisted in embolization alone in 34%, embolization followed by surgery in 47%, embolization and radiotherapy in 16%, and embolization, surgery and radiotherapy in 3% of patients. The embolization procedure itself could lead to an angiographic cure in only 16% of patients. When the management strategy could be completed, the cure rate increased to 66%. Complications of embolization occurred in 22.6% of patients. Overall clinical outcome was excellent (Rankin 0) in 43%, good (Rankin 1) in 38%, fair (Rankin 2) in 10%, poor (Rankin 3-5) in 2%, and the death rate was 7%. A combined strategy initially designed to provide angiographic cures cannot be completed in a significant number of patients; the total morbidity of treatment remains significant. There is no scientific evidence that cerebral arteriovenous malformations should be treated, and no clinical trial to prove that one approach is better than the other. Various treatment protocols have been proposed on empirical grounds. Small lesions can often be eradicated, with surgery when lesions are superficial, or with radiation therapy for deeper ones. There has been little controversy regarding therapeutic indications in these patients (1). The management of larger AVMs, sometimes in more eloquent locations, is much more difficult and controversial (2-4). Endovascular approaches have initially been developed to meet this challenge (5,6). It became quickly evident that embolization alone would rarely suffice to completely cure these lesions. The philosophy behind combined approaches is founded on 2 opinions: 1) There is no proven value of partial embolization, not even "partial benefits", and treatment should aim at an angiographic cure (7) and 2) By appropriately tailoring all available tools to each situation, such a cure could be reached with minimum or reasonable risks. We have used such a combined strategy for more than a decade now. Endovascular techniques and materials have evolved, and it is perhaps possible today to reach a cure by embolization alone in a larger proportion of patients than before (8). Aggressive embolizations, aiming for an endovascular cure, even sometimes in large lesions, have recently been promoted for their power or criticized for their risks (9). But before evaluating the advantages and inconveniences of new treatments, it may be wise to review the results we could achieve with a conventional approach combining endovascular, surgical and radiotherapeutic techniques.