Increased carotid wall stress in vascular Ehlers-Danlos syndrome

Background - Vascular Ehlers-Danlos syndrome (vEDS), also known as EDS type IV, an inherited disorder of connective tissue, results from mutations in the gene encoding type III procollagen (COL3A1). Affected patients are at risk for arterial dissection or rupture, the main cause of death. To understand the pathogenesis of the vascular lesions, we used a biomechanical approach and determined steady and pulsatile wall stress. Methods and Results - Sixteen patients with vEDS and 16 age-, gender-, and blood pressure - matched control subjects were included in this cross-sectional noninvasive study. Circumferential wall stress was determined under steady and pulsatile conditions at the site of an elastic (common carotid) and a muscular (radial) artery from the measurements of intima-media thickness and internal diameter with high-resolution echo-tracking systems and either mean blood pressure or pulse pressure, respectively. At the site of the carotid artery, steady circumferential wall stress was 43% higher in vEDS patients than in control subjects (68.9 +/- 14.3 versus 48.2 +/- 12.1 kPa, P < 0.001), and pulsatile circumferential wall stress was 22% higher (28.2 +/- 7.7 versus 23.1 +/- 5.7 kPa, P < 0.001). Carotid intima-media thickness was 32% lower (408 +/- 56 versus 598 +/- 171 mum, P < 0.001) in vEDS patients, and internal diameter was not different between groups. Radial artery parameters were not significantly different between groups. Conclusions - In vEDS patients, an abnormally low intima-media thickness generates a higher wall stress than in control subjects at the site of an elastic artery, which may increase the risk of arterial dissection and rupture.