Bleeding source identification and treatment in brain arteriovenous malformations.

Arteriovenous malformation (AVM) patients who initially present with intracerebral haemorrhage may have an identifiable source of bleeding on angiogram, which can be a treatment target. Previous work suggests that the re-bleed rate may be lowered if a weak area is eliminated.A retrospective cohort study was conducted on patients who presented over a six-year period with a bled AVM. Cases were reviewed looking for the source of the hemorrhage by correlating haematoma location on CT or MRI and any angio-architectural weakness seen on digital subtraction angiography (DSA). Neuroendovascular notes were reviewed to identify the treatment targets. One hundred patients presented with a brain AVM with a 1.7:1 male: female ratio, 41 patients had an initial presentation of hemorrhage. The source of hemorrhage was identified in 18 subjects with 11 intranidal false aneurysms, five flow-related aneurysms, two associated aneurysms and one venous pouch. The location of haemorrhage on the presenting scan significantly correlated with the identified bleeding source using Chi-square analysis (P-value 0.039). Partial targeted embolization was used successfully in 90% with a 9% related technical complication rate not resulting in long-term morbidity or mortality. The mean follow-up period was 34 months with an annual hemorrhage rate of 0.7%. In just under half the patients with AVM bleeding a source of haemorrhage can be identified on DSA and in most cases this will be an intranidal false aneurysm. Flow-related and associated aneurysms in patients with brain AVM can cause haemorrhage and these patients are more likely to have SAH than intracerebral haemorrhage.These weak points are a good target for partial endovascular treatment, are usually accessible and may reduce the higher haemorrhage rate expected over the next two years.