Are there systemic changes in the arterial biomechanics of intracranial aneurysm patients?

Current theories on the development of intracranial aneurysm suggest that t here is a general weakness of vascular connective tissue. Potential systemi c alterations in arterial wall biomechanics were tested in the present stud y. A three-dimensional in vitro stress-strain analysis was made in the 0-20 0-0 mmHg pressure range on cylindrical segments excised from the anterior c erebral artery, the radial artery and from the arteria dorsalis pedis of an eurysm patients and of control cadavers. In the anterior cerebral artery fr om aneurysm patients (intracranial artery segments directly not affected by the aneurysm or by the subarachnoid bleeding), we found the wall thickness to be larger (0.148+/-0.019 versus 0.091+/-0.004 mm), the radius/wall thic kness ratio smaller (9.7+/-1.4 versus 14.1+/-1.2), and the tangential wall stress lower [(0.122+/-0.019)x10(6) versus (0.181+/-0.016)x10(6) N/m(2) at 100 mmHg] than in control subjects. Reduced radius was found in the extremi ty arteries studied. Elastic parameters, as incremental distensibility and elastic modulus, were remarkable similar. Our study demonstrates changes in the geometry of walls of arteries not directly affected by aneurysm format ion, and it thus confirms systemic vascular pathology in this disease. At t he same time, these data show that the molecular and morphological defects of arterial connective tissue formation generally thought to induce intracr anial aneurysms will probably not affect the components responsible for the passive elastic properties of the vascular wall.