A novel predictor of ischemic complications in the treatment of ruptured middle cerebral artery aneurysms: Neck-branching angle

Objective The risk factors of procedural cerebral ischemia (CI) in ruptured middle cerebral artery (MCA) aneurysms are unclear. This study proposed the neck-branching angle (NBA), a simple quantitative indicator of the aneurysm neck and branch vessels, and analyzed its usefulness as a predictor of procedural CI in ruptured MCA aneurysms. Methods We retrospectively analyzed 128 patients with ruptured saccular MCA aneurysms who underwent surgical or endovascular treatment between January 2014 and June 2021. We defined the NBA as the angle formed by the MCA aneurysm neck and M2 superior or inferior branch vessel line. The superior and inferior NBA were measured on admission via three-dimensional computed tomography angiography on admission. We divided the patients into clipping (106 patients) and coiling (22 patients) groups according to the treatment. Risk factors associated with procedural CI were analyzed in each group. Results Both groups showed that an enlarged superior NBA was a significant risk factor for procedural CI (clipping, P < 0.0005; coiling group, P = 0.007). The receiver operating characteristic curve showed the closed thresholds of the superior NBA with procedural CI in both groups (clipping group, 128.5°, sensitivity and specificity of 0.667 and 0.848, respectively; coiling group, 130.9°, sensitivity and specificity of 1 and 0.889, respectively). Conclusion The NBA can estimate the procedural risk of ruptured MCA aneurysms. In addition, an enlarged superior NBA is a risk factor for procedural CI in both clipping and coiling techniques.