Reference values of the carotid elastic modulus using shear wave elastography and arterial stiffness change in coronary slow flow.

Purpose: Shear wave elastography (SWE) accurately and sensitively evaluates arterial wall stiffness by quantifying the elastic modulus (EM); however, the absence of reference values has precluded its widespread clinical application. This prospective cohort study aimed to establish reference values for the carotid EM using SWE; investigate the main determinants of the EM; and evaluate EM changes in coronary slow flow (CSF), which is characterized by delayed coronary opacification without evident obstructive lesion in epicardial coronary artery on angiography.

Method: This study enrolled 169 healthy volunteers and 30 patients with CSF. The carotid maximum EM (EMmax), mean EM, and minimum EM were measured using SWE. CSF was diagnosed by thrombolysis in the myocardial infarction frame count during coronary angiography.

Results: No differences were found in the EM between the left and right carotid arteries and between men and women. Multiple linear regression analysis revealed that age was independently correlated with the EMmax, which progressively increased with age. Moreover, smoking had an independent influence on the EM after adjusting for age; smokers had higher EM than non-smokers. Age-specific reference values for the carotid EM were established. The EM was higher in patients with CSF than in controls after adjusting for age and smoking status.

Conclusions: This study first established the reference values for the carotid EM using SWE. Age and smoking status were the main determinants of the EM. Patients with CSF had high EM. SWE can effectively and noninvasively evaluate arterial stiffness in patients with CSF.