ARUBA results are not applicable to all patients with arteriovenous malformation.

or brain arteriovenous malformations (AVMs), rupture represents the primary concern. Both prospective and retrospective observational studies have helped to define the natural history of AVMs and highlight potential risk factors. Estimates for bleeding from unruptured AVMs range from 1.3% to 4% per year 1,2 with mortality of 10% to 30% from incident hemorrhage and neurological disability of 20% to 30%. Angioarchitectural features (eg, intranidal aneurysms, exclusive deep drainage, and restricted venous outflow), lesional features (eg, small size and deep location), and patient-specific features (eg, age, seizure history, and pregnancy) have all been described as affecting the rupture risk. The efficacy and risk of treatment vary based on the modality used (surgical, endovascular, or radiosurgical) and AVM specific location and features. For surgical treatment, the most robust risk stratification is based on the Spetzler–Martin classification 3 that considers size, eloquence, and venous drainage in a 5-point scale, which predicts 95% to 100% excellent outcome for grade 1 to 2 AVMs and 50% to 73% for grade 4 to 5 AVMs. 3,4 Consequently, the former are typically considered favorable for surgical intervention and the latter, high risk. This places grade 3 AVMs in the gray zone, whereby additional stratification focused on each of the elements of the grading system reveals variability in risk, which can range from 3% to 15% dependent on specific features. 5 Parallel, but modality-specific, classification systems predicting treatment risk after radiosurgery and endovascular embolization have also been developed. In addition, the treatment options vary in regards to expected timeframe to eradication, ranging from immediate durable cure with surgery to delayed obliteration >2 to 3 years with radiosurgery. Any treatment offered must be individualized to the specific AVM, and similarly, the choice of modality may substantially alter the outcome. Given the unique features of any given AVM, which may dictate prognosis and treatment outcome, the patient in question should certainly be referred to a specialist for evaluation of treatment options. With a life expectancy of ≈60 years, her lesion conservatively carries a lifetime rupture risk of 70%. If she becomes pregnant, recent data additionally indicates an 8-fold risk of puerperal hemorrhage. Based on the grade 3 designation, this 4-cm AVM may either have deep drainage or reside in eloquent territory; dependent on those specific features, choice of treatment modality can be tailored to achieve an expected >90% favorable outcome. 6 Weighing these options, treatment becomes the clearly superior strategy, …