Relationship between the morphology of A-1 segment of anterior cerebral artery and anterior communicating artery aneurysms

Classification of anterior communicating aneurysms on a basis of endovascular treatments

BACKGROUND AND PURPOSE

The anterior communicating artery (Acoma) aneurysms are difficult to understand because of their anatomical variations. This study reported a new classification of Acoma aneurysms on a basis of endovascular treatments.

METHODS

This retrospective study enrolled consecutive 94 patients harbored 100 Acoma aneurysms treated with coil embolization. All Acoma aneurysms were classified into 5 orientations (straight, superior, inferior, anterior, and posterior) based on the axis connecting A1 origin and the base of the aneurysm. Aneurysm characteristics, endovascular treatments, angiographic, and clinical outcomes were evaluated using this classification.

RESULTS

According to this classification, there were 64 (64%) straight, 16 (16%) inferior, 16 (16%) superior, 2 (2%) anterior, and 2 (2%) posterior projection aneurysms. There were significant differences between different groups in aneurysm height (p=0.009) and aneurysm neck size (p = 0.003), and in endovascular treatments (p=0.006). There was a significant difference in the proportion of rupture presentation among the three groups of straight, inferior, and superior (p = 0.019). There was no difference in the results of postoperative angiography (p = 0.090). An excellent functional outcome with an mRS ≤1 was achieved in 91 (96.8%) patients.

CONCLUSIONS

This classification of Acoma aneurysms based on the axis connecting A1 origin and the base of the aneurysm is associated with aneurysm height, aneurysm neck size, and in need for stent-assisted therapy. Endovascular embolization can provide the same effective treatment for aneurysms in all directions.

Association between Circle of Willis Configuration and Rupture of Cerebral Aneurysms

Background and Objectives: Intracranial hemorrhage caused by the rupture of brain aneurysms occurs in almost 10 per 100,000 people whereas the incidence of such aneurysms is significantly higher, accounting for 4–9%. Linking certain factors to cerebral aneurysm rupture could help in explaining the significantly lower incidence of their rupture compared to their presence. The aim of this study is to determine the association between the corresponding circle of Willis configurations and rupture of cerebral aneurysms. Materials and Methods: A group of 114 patients treated operatively for aruptured cerebral aneurysm and a group of 56 autopsied subjects were involved in the study. Four basic types of the circle of Willis configurations were formed—two symmetric types A and C, and two asymmetric types B and D. Results: A statistically significantly higher presence of asymmetry of the circle of Willis was determined in the group of surgically-treated subjects (p = 0.001),witha significant presence of asymmetric Type B in this group (p < 0.001). The changeson the A1 segment in the group of surgically-treated subjects showed a statistically significant presence compared to the group of autopsied subjects (p = 0.001). Analyzing the presence of symmetry of the circle of Willis between the two groups, that is, the total presence of symmetric types A and C, indicated their statistically significant presence in the group of autopsied patients (p < 0.001). Conclusions: Changes such as hypoplasia or aplasia of A1 and the resulting asymmetry of the circle of Willis directly affect the possibility of the rupture of cerebral aneurysms. Detection of the corresponding types of the circle of Willis after diagnostic examination can be the basis for the development of a protocol for monitoring such patients.