Introduction: The prognosis of arteriovenous malformations (AVMs) after treatment has been largely predicted by two grading scales: Spetzler-Martin and Pollock-Flickinger. Although there are studies examining hemorrhage rate using the Spetzler-Martin grading scale, there haven’t been studies examining hemorrhage rate using the Pollock-Flickinger grading scale. The annual risk of AVM hemorrhage after radiosurgery of Pollock-Flickinger AVM score greater than 2 is analyzed.
Methods: Literature search on PubMed for radiosurgical treatment of AVMs with a score of at least 2 from year 2000-present was conducted. Performed meta-analysis of all nine papers which fit the criteria previously stated in order to analyze hemorrhage rate of AVMs. Performed a second analysis of six of the papers which separated hemorrhage and rehemorrhage rate. Performed third analysis of natural history of rehemorrhage.
Results: Annual AVM hemorrhage rate after radiosurgery for all patients (n=673) was 3.32% (102.3 hemorrhages, 3080.5 follow-up years, 95% CI, 2.83%-4.15%). Mortality rate from hemorrhage was 40.08% (41 deaths, 95% CI, 31.21% - 49.90%) and overall mortality rate was 6.29% (42 deaths, 95% CI, 4.65% - 8.33%). Based on information provided, 203 patients presented with hemorrhage and 395 did not. The annual hemorrhage rate of those with hemorrhagic presentation was 6.10% (42.6 re-bleeds, 765.40 follow-up years, 95% CI, 4.65% - 8.07%). In patients who didn’t present with hemorrhage, the annual hemorrhage rate was 3.53% (46.7 bleeds, 1205.23 follow-up years, 95% CI, 2.66% - 4.77%). The odds ratio comparing rate of re-hemorrhage versus first-time hemorrhage after radiosurgery is 1.768 (95% CI, 1.1571-2.7014, P = 0.0084).
Conclusions: The annual hemorrhage rate in AVMs with a minimum score of 2 treated with radiosurgery was comparable in this series to the baseline rupture rate reported for untreated AVMs. In addition, separating hemorrhagic versus non-hemorrhagic presentation, subsequent annual hemorrhage rates are similar to respective natural histories.
Patient Care: This research will allow clinicians to better council patients with AVMs on the efficacy of radiosurgery and the rate of associated hemorrhage and rehemorrhage after treatment.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Understand the rate of AVM hemorrhage and rehemorrhage after radiosurgery 2) Understand the natural history of AVM rehemorrhage 3) Better council patients on the effectiveness of radiosurgery