Increased stiffness of the carotid wall material in patients with spontaneous cervical artery dissection

The cause of spontaneous cervical artery dissection (sCAD) is largely unknown. An underlying connective tissue disorder has often been postulated, but arterial mechanical properties have rarely been studied. The study aim was to determine the elastic properties of a cervical artery, the common carotid artery, and a distal muscular artery, the radial artery in sCAD patients.

We studied 32 patients with previous sCAD (median delay: 2.2 years) and 32 control subjects with similar age and blood pressure. Internal diameter, intima-media thickness, distensibility, and Young's elastic modulus were determined at the site of the right and left common carotid arteries and the radial artery using noninvasive high-resolution echotracking systems.

In patients with previous sCAD, cross-sectional distensibility and compliance of the affected carotid artery did not differ from those of the contralateral carotid artery. Young's elastic modulus (ie, the stiffness of the wall material) was 58% higher (0.44+/-0.32 versus 0.28+/-0.15 kPa.10(3), P<0.001) and circumferential wall stress was 14% higher (56+/-12 versus 49+/-12 kPa, P<0.001) in sCAD patients than in controls. The highest tertile of common carotid artery Young's elastic modulus was associated with an 8-fold higher risk of sCAD. Aortic stiffness, assessed from the carotid-femoral pulse wave velocity, and radial artery parameters did not differ between sCAD and controls.

Carotid arteries, but not aorta and radial artery, displayed abnormal elastic properties in sCAD patients. Higher stiffness of carotid wall material and circumferential wall stress could increase the risk of dissection in these patients.