| Abstract: | In order to elucidate hemodynamic characteristics of the circle of Willis in patients with saccular aneurysms and the causative relationship linking saccular aneurysms and hypertension, branches of the circle of Willis from 21 patients with ruptured aneurysms and of seven normotensive and eight hypertensive controls were histometrically investigated. The 21 aneurysm cases consisted of 12 single, four multiple and five single giant aneurysms. Among these 21 patients, 11 had no clinical history of systemic hypertension. Histometric analysis revealed that the average thickness of the media of the resistance vessels in the circle of Willis in all 21 patients was significantly greater than that of the normotensive control group (P < 0.001), and that the mean thickness of the whole aneurysm group was almost equal to that of the hypertensive control group (t= 0.102). Moreover, the difference between 11 aneurysm patients without clinical history of hypertension and 10 aneurysm patients with clinical history of hypertension was insignificant (t= 1.293). Based on these data, we conclude that an increased local hemodynamic stress with hypertensive alterations of the arterial wall is prerequisite for the development of cerebral saccular aneurysm even in patients without a history of systemic arterial hypertension. |
