Interventions for treating brain arteriovenous malformations in adults

Background Brain arteriovenous malformations (AVMs) are the single most common cause of intracerebral haemorrhage in young adults. Brain AVMs also cause seizure(s) and focal neurological deficits (in the absence of haemorrhage, migraine or an epileptic seizure); approximately one fifth are incidental discoveries. Various interventions are used in an attempt to eradicate brain AVMs: neurosurgical excision, stereotactic radiotherapy/'radiosurgery' (using gamma knife, linear accelerator or proton beam), endovascular embolisation (using glues, particles, fibres, coils, or balloons), and staged combinations of these interventions. Objectives To assess the clinical effects of interventions to treat brain AVMs in adults (with the aim of either partial obliteration or total eradication), using data published in randomised controlled trials. Search strategy We searched: (1) the Cochrane Stroke Group Register (last searched December 2004); (2) medical literature databases (MEDLINE 1966 to 31 December 2004 and EMBASE 1980 to 31 December 2004); (3) on-line and paper journal surveillance; (4) the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2005); (5) international registers of clinical trials; (6) bibliographies of relevant articles identified by (1) to (5); and (7) we sought unpublished data from manufacturers of interventional treatments for brain AVMs. Selection criteria We sought randomised trials of any or all of the interventions for brain AVMs, compared against each other or against usual medical therapy, with relevant clinical outcome measures. Data collection and analysis Two authors independently applied the inclusion criteria and reviewed the relevant studies. Main results We did not find any randomised trials meeting our selection criteria. We found two randomised trials which tested the equivalence of two embolic agents for the pre-operative embolisation of brain AVMs (one published, one unpublished), but none of the primary or secondary outcome measures in these trials met our desired criteria; although important clinical outcomes were reported, meaningful comparison of the two treatment arms was impossible. We also excluded a third RCT which studied three different blood pressure lowering treatments to induce deliberate hypotension during surgical resection of brain AVMs, because the intervention was not the focus of this review.