Experimental determination of rupture pressure and stress of adventitia of human middle cerebral arteries

Rupture pressure values of cerebral arteries in the presence of unruptured intracranial aneurysm

Cerebral arteries (CAs) are prone to the saccular aneurysm formation. Since aneurysms may be considered as balloon-like dilations of the locally weakened arterial wall, it should be determined whether the presence of intracranial aneurysm is related to the generalized weakening of CAs. Among 184 consecutive forensic autopsies, eight brains with a single unruptured saccular aneurysm were identified. Aneurysms with adjacent CAs and specific CA segments were excised, namely: the anterior communicating artery complex, and bifurcations of the basilar artery, internal carotid arteries, and middle cerebral arteries. Then, aneurysm and CA specimens were subjected to pressure-inflation tests until rupture occurred at the arterial bifurcation or at the wall of the CA or aneurysm. The same protocol was applied to the control group composed of CAs excised from eight brains without aneurysm. No significant differences were noted between the experimental and control groups, depending on the mean rupture pressure (1054 vs. 1048 mmHg) and rupture site (bifurcation vs. wall) of the analyzed specimens. These findings indicate that the presence of unruptured saccular aneurysm is not related to generalized weakening of CAs among autopsy subjects. Moreover, the CA bifurcations do not represent regions of decreased wall strength.