Introduction: The primary goal of brain AVM treatment is to reduce hemorrhagic risk. However, post-treatment hemorrhagic risk exists, and has been reported separately for different treatment modalities: annual rate of 1% after surgery, 10% after embolization, and 2-7% after radiosurgery. We aim to compare the risk of delayed hemorrhages across different treatment modalities in a single study cohort.
Methods: Our study included patients diagnosed with brain AVMs treated at Johns Hopkins Hospital and Johns Hopkins Bayview Medical Center. Patients with multiple AVMs or with hereditary hemorrhagic telangiectasia(HHT) were excluded. Delayed hemorrhage was defined as hemorrhage occurring at least 2 years after treatment. Proportion of delayed hemorrhage and patient-time statistics were used to assess hemorrhagic risks by treatment modality.
Results: A total of 205 patients were included after application of inclusion and exclusion criteria. Spetzler-Martin grades were: I(n=35,17.1%), II(n=77,37.6%), III(n=58,28.3%), IV(n=32,15.6%), V(n=3,1.5%). Eleven patients(5.4%) were found to have a total of 16 delayed hemorrhage events. Among these, three patients were previously confirmed to have no residual AVMs by angiography. Average interval between last treatment and delayed hemorrhage was 16.5 years, with the longest interval as 28.7 years. Proportions of delayed hemorrhages by treatment modalities(p<0.01) were: surgery(1.6%), radiosurgery(4.0%), embolization(11.1%) and multimodality(50.0%). Patient-times of delayed hemorrhages by treatment modalities were: surgery(5.9/1000 patient-years), radiosurgery(14.3/1000 patient-years), embolization (25.4/1000 patient-years), and multimodality(79.7/1000 patient-years). Of note, there was no significant difference between surgery and radiosurgery cohort on a poisson-rate-test (p=0.67)
Conclusions: Delayed hemorrhages may occur after AVM treatment, even after angiographic confirmation of obliteration. Control for delayed hemorrhage between radiosurgery and surgery was not found to be statistically different. Multimodality managed patients have lower Spetzler-Martin grades than radiosurgery patients, yet they present with the highest rate of delayed hemorrhage.
Patient Care: The result of our study alerts physicians that AVMs might hemorrhage after confirmed obliteration. It also emphasizes the point that patients need to be followed regularly in clinics even though the lesion is considered to be stabilized to allow prompt management in case of delayed hemorrhagic events.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Understand that there are risks of delayed hemorrhages (> 2 years post-treatment) after AVM treatment.
2) Understand the difference of delayed hemorrhagic risk control for different modalities.
3) Identify the fact that AVM may hemorrhage after angiographically confirmed obliteration.