1073. Effect of Advanced Age on Stereotactic Radiosurgery Outcomes for Brain Arteriovenous Malformations: A Multicenter Matched Cohort Study

Authors: Ching-Jen Chen, MD; Dale Ding, MD; Hideyuki Kano, MD; David Mathieu, MD; Douglas Kondziolka, MD; Caleb Feliciano, MD; Rafael Rodriguez-Mercado, MD; Darrah Sheehan; Inga Grills, MD; Dade Lunsford, MD; Jason Sheehan, MD, PhD; Gene Barnett, MD (Charlottesville, VA)

Introduction: The aim of this multicenter, retrospective matched cohort study of stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVM) is to compare outcomes between elderly and non-elderly adult patients. Methods: We retrospectively reviewed pooled data comprising patients who underwent SRS for AVMs between 1987 and 2014 at eight centers participating in the International Gamma Knife Research Foundation (IGKRF). Adult (age ≥18 years) patients with ≥12 months follow-up were dichotomized into elderly (≥60 years old) and non-elderly (<60 years old) cohorts, and matched in a 1:1 ratio using propensity scores. Favorable outcome was defined as AVM obliteration without permanent symptomatic radiation-induced changes (RIC) or post-SRS hemorrhage. Results: The study cohort consisted of1,845 patients (elderly n=188 vs. nonelderly n=1,657) who met the inclusion criteria, and subsequent matching resulted in 181 patients in each cohort. In the matched cohorts, rates of obliteration (54.7% vs. 64.6%, p=0.054) favorable outcome (51.4% vs. 61.3%, p=0.056) were no different between the elderly and nonelderly cohorts.The rates of post-SRS hemorrhage (9.9% vs. 5.5%, p=0.115), RIC (26.5% vs. 30.9%, p=0.353), symptomatic RIC (9.4% vs. 9.4%, p=1.000), and permanent symptomatic RIC (3.3% vs. 2.2%, p=0.750) were also not significantly different between the elderly and non-elderly cohorts.Elderly AVM patients did have a significantly higher rate of all-cause mortality (27.7% vs. 5.5%, p<0.001). Conclusion: Advanced age does not appear to significantly impact obliteration or complication rates after SRS for AVMs. Although the decision to recommend intervention for AVMs in the elderly population is multifactorial, SRS may be a preferred modality when treatment is deemed appropriate. One should consider that elderly AVM patients are still subject to other causes of age-related mortality independent of AVM-related neurological injury.