Surgery for unruptured arteriovenous malformations of the brain is better than conservative management for selected cases: a prospective cohort study

Abstract

Object The aim of this study was to identify patients who are likely to benefit from surgery for unruptured brain arteriovenous malformations (ubAVMs). Methods The authors' database was interrogated for the risk and outcome of hemorrhage after referral and the outcome from surgery. Furthermore, the outcome from surgery incorporated those cases excluded from surgery because of perceived greater risk (sensitivity analysis). Finally, a comparison was made for the authors' patients between the natural history and surgery. Data were collected for 427 consecutively enrolled patients with ubAVMs in a database that included patients who were conservatively managed. Kaplan-Meier analysis was performed on patients observed for more than 1 day to determine the risk of hemorrhage. Variables that may influence the risk of first hemorrhage were assessed using Cox proportional hazard regression models and Kaplan-Meier life table analyses from referral until the first occurrence of the following: hemorrhage, treatment, or last review. The outcome from surgery (leading to a new permanent neurological deficit with last review modified Rankin Scale [mRS] score > 1) was determined. Further sensitivity analysis was made to predict risk from surgery for the total ubAVM cohort by incorporating outcomes of surgical cases as well as cases excluded from surgery because of perceived risk, and assuming an adverse outcome for these excluded cases. Results A total of 377 patients with a ubAVM were included in the analysis of the risk of hemorrhage. The 5-year risk of hemorrhage for ubAVM was 11.5%. Hemorrhage resulted in an mRS score > 1 in 14 cases (88% [95% CI 63%–98%]). Patients with Spetzler-Ponce Class A ubAVMs treated by surgery (n = 190) had a risk from surgery of 1.6% (95% CI 0.3%–4.8%) for a permanent neurological deficit leading to an mRS score > 1 and 0.5% (95% CI < 0.1%–3.2%) for a permanent neurological deficit leading to an mRS score > 2. Patients with Spetzler-Ponce Class B ubAVMs treated by surgery (n = 107) had a risk from surgery of 14.0% (95% CI 8.6%–22.0%) for a permanent neurological deficit leading to an mRS score > 1. Sensitivity analysis of Spetzler-Ponce Class B ubAVMs, including those in patients excluded from surgery, showed that the true risk for surgically eligible patients may have been as high as 15.6% (95% CI 9.9%–23.7%) for mRS score > 1, had all patients who were perceived to have a greater risk experienced an adverse outcome. Patients with Spetzler-Ponce Class C ubAVMs treated by surgery (n = 44) had a risk from surgery of 38.6% (95% CI 25.7%–53.4%) for a permanent neurological deficit leading to an mRS score > 1. Sensitivity analysis of Class C ubAVMs, including those harbored by patients excluded from surgery, showed that the true risk for surgically eligible patients may have been as high as 60.9% (95% CI 49.2%–71.5%) for mRS score > 1, had all patients who were perceived to have a greater risk experienced an adverse outcome. Conclusions Surgical outcomes for Spetzler-Ponce Class A ubAVMs are better than those for conservative management.

Microsurgery for ARUBA Trial (A Randomized Trial of Unruptured Brain Arteriovenous Malformation)–Eligible Unruptured Brain Arteriovenous Malformations

“…1 Both SIVMS and ARUBA cohorts had predominantly nonsurgical interventions and bAVM obliteration rates of 63% to 71% were observed in SIVMS. 16 In contrast, Bervini et al 35 presented a 25-year microsurgical series from Sydney, Australia, of 427 unruptured bAVMs patients, who were stratified according to the Spetzler-Ponce class 4 : for class A (n=190), the rate of permanent neurological deficit with mRS increase >1 was 1.6% (95% confidence interval, 0.3-4.8%); class B (n=107), 14.0% (95% confidence interval, 8.6-22.0%); and class C (n=44), 38.6% (95% confidence interval, 25.7-53.4%). 35,36 Subsequent sensitivity analyses on the same database by Korja et al 37 showed no statistical difference to the combined classes A and B adverse outcome rate of 7.7% when nonoperated patients were assumed to have adverse outcomes.…”

Treatment of unruptured brain AVM in the aftermath of ARUBA and the Scottish Audit of Intracranial Vascular Malformations

“…The recent work of Bervini and colleagues, Nerva and colleagues, as well as the report in the current issue provide sufficient substance to recommend microsurgery to patients with unruptured AVM Spetzler-Martin grade 1 and 2 (corresponding to Spetzler-Ponce class A) [3,11,14,16]. In contrast, treatment of unruptured Spetzler-Martin grade 3 and 4 AVMs needs to be seen critically.…”

Responses to ARUBA: a systematic review and critical analysis for the design of future arteriovenous malformation trials

“…[2][3][4]10,11,20,[22][23][24]31,36,43 A related concern was the aggregation of the various treatment modalities that perhaps preferably should have been tested separately. 2,5,10,11,13,18,20,[23][24][25]33,43,46,53 The approach adopted by ARUBA's designers was that the variety of patients and treatment choices were a fact of life, to be accepted as such. 29 Heterogeneity can provide in ductive strength to pragmatic trial results.…”