Introduction: Following stereotactic radiosurgery (SRS) for treatment of arteriovenous malformations (AVMs), there is a latency period until obliteration, during which patients continue to be at risk for hemorrhage. We aim to clarify this risk and present 10 cases of AVM hemorrhage following SRS.
Methods: We performed a retrospective review of all AVM patients admitted between 1993 and 2010 at our institution. We identified 10 patients who were diagnosed with AVMs by digital subtraction angiography(DSA), treated with SRS, and developed hemorrhage after SRS.
Results: Mean age at time of first treatment was 31.9±7.9 years, with 90% of patients being female(n=9). Forty percent (n=4) presented initially with hemorrhage. Spetzler-Martin grades were: I for 10% of patients, II for 20%, III for 30%, IV for 30%, and V for 10%. The mean prescription dose was 15.1±4.5 Gy. A total of eleven hemorrhagic events following SRS were observed. One patient developed hemorrhage after each of two SRS treatments, and two patients hemorrhaged after receiving three courses of SRS. The interval between SRS and subsequent hemorrhage was 44.2±42.8 months. Of these 10 patients who had hemorrhage after SRS, eventual AVM obliteration was confirmed in only two. Notably, one patient hemorrhaged 54 months after complete AVM obliteration had been confirmed by DSA.
Conclusions: Hemorrhage after SRS for AVMs is rare and the timing of such hemorrhage is variable. However, in those treated with SRS who subsequently hemorrhaged, the likelihood of eventual AVM obliteration was low, and observed in only 20%. Given the possibility of AVM hemorrhage following SRS, both after the latency period and even after confirmed angiographic obliteration, close follow-up is warranted for AVMs treated with SRS.
Patient Care: Our study shows that recurrent hemorrhages can happen during latency period of SRS in AVM patients. The identification of this phenomenon improves patient education in hemorrhagic risk and warrants close follow-up of AVM patients following SRS.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Describe the major risks and outcomes of stereotactic radiosurgery in the treatment of arteriovenous malformations
2) Discuss, in small groups, the possible factors associated with hemorrhage following stereotactic radiosurgery
3) Identify the importance of follow-up in patients status post stereotactic radiosurgery