The Rate of Symptomatic Ischemic Events after Passing Balloon Test Occlusion of the Major Intracranial Arteries: Meta-Analysis

Background: Balloon test occlusion is a widely used method for predicting tolerance of vessel occlusion in the treatment of aneurysms, fistulae, and head and neck neoplasms. However, the false-negative rate is variably reported due in part to the diversity of perfusion monitoring methods. Objective: To evaluate the rate of symptomatic ischemic events after a negative balloon test occlusion and determine whether perfusion monitoring methods contribute to differences in these rates. Methods: PubMed was systematically searched for studies between 1990 and 2020 that reported rates of ischemic outcomes of parental vessel occlusion in patients who passed balloon test occlusion. A generalized linear mixed model meta-analysis was performed. Results were expressed as the rate of symptomatic ischemic events after parental vessel occlusion without vessel bypass in patients who passed balloon test occlusion. Results: Thirty-two studies met the inclusion criteria. The overall pooled rate of ischemic events after passing balloon test occlusion was 3.7% (95% confidence interval [CI]: 1.7–7.8). This rate was 3.8% (95% CI: 1.1–12.8) when monitored with angiography, 2.2% (95% CI: 0.4–10.2) when monitored by a form of computed tomography, and 5.3% (95% CI: 1.2–20.4) when monitored by 2 or more methods of perfusion assessment. The complication rate of balloon test occlusion was 0.8% (95% CI: 0.2–2.7). Conclusions: Balloon test occlusion results in a low rate of subsequent ischemic events, without conclusive evidence of variation between methods of perfusion assessment. The choice of method should focus on reduction of complication risk, experience of the interventional team, and avoidance of prolonged test occlusion times.