Background and purpose: The aim of this study was to assess frequency of main symptoms of the supratentorial arteriovenous malformations (AVM) and attempt to find factors influencing their occurrence.
Material and methods: 88 consecutive patients operated on for AVM located supratentorially in the years 1983-2000 were included in a retrospective analysis. Statistical analyses including chi-square test and exact Fisher test were performed for comparisons among groups.
Results: The most common cause of diagnostics was intracranial hemorrhage--62.5%. Epilepsy, headaches and non-hemorrhagic focal deficits were described in 38.6%, 9.1% and 4.5%, respectively. Deterioration (focal deficits and/or disturbances of consciousness) after hemorrhage occurred in 30%. The risk of hemorrhage from AVM was 2.2% per year. Hemorrhage was more frequent in the cases of small size (<3 cm) of AVM (p=0.001), deep location (p<0.05) and when single (p=0.001) and exclusively deep (p<0.05) venous drainage were present. However, superficial location of AVM and nidus size >3 cm significantly influenced epilepsy occurrence (p<0.05 and p=0.001, respectively). Sex and coexisting aneurysm did not influence occurrence of epilepsy or hemorrhage.
Conclusions: Supratentorial AVMs manifest most common as intracranial hemorrhage and epilepsy. Factors increasing the risk of hemorrhage are: small size, deep location of AVM, single and exclusively deep venous drainage. Factors increasing the risk of epilepsy are: superficial location and size >3 cm.