Common carotid artery stiffness in patients with Spontaneous Coronary Artery Dissection (SCAD) is comparable to non-dissection controls

Background: Arterial dissection is a rare but potentially life-threatening condition, hypothesized to be linked to changes in vessel wall elasticity. This study aimed to provide an insight into the pathophysiology of arterial dissection by assessing whether elasticity of the common carotid artery (CCA) differs between patients with confirmed spontaneous coronary artery dissection (SCAD) and non-dissection controls. Methods: Ultrasound shear wave elastography (SWE) estimates of artery wall elasticity were obtained from the left and right CCAs of 89 confirmed SCAD patients and 38 non-dissection controls. SWE images obtained over multiple cardiac cycles were analysed by a blinded observer to estimate elasticity in the form of a Young’s Modulus (YM) value, across regions of interest (ROI) located within the anterior and posterior CCA walls. A confidence limit on the difference in mean YM between SCAD patients and non-dissection controls was estimated. Results: YM estimates ranged from 17 to 133 kPa in SCAD patients compared to 34 to 87 kPa in non-dissection controls. The mean YM of 55 [SD: 21] kPa in SCAD patients was not significantly different to the mean of 57 [SD: 12] kPa in controls, p = 0.32. The difference between groups was 2 kPa [95%CI: -11, 4]. Conclusions: We found no evidence of a significant difference in elasticity of the CCA between SCAD patients and non-dissection controls. This suggests that widespread changes in arterial compliance are not a major factor in the pathogenesis of arterial dissection.