Suggestion for a new image-based aortic wall stiffness evaluation technique: arterial wall stiffness index.

This study evaluated arterial wall stiffness independent of variant background blood pressure. A new technique-arterial wall stiffness index (AWSI)-was developed and its use verified. Intraluminal pressure and luminal volume were measured on eight swine descending aortas. AWSI was formulated to evaluate absolute arterial wall stiffness independent of variable blood pressure and aortic size. AWSI variability with pressure change was compared with other wall stiffness evaluation parameters. AWSI determined from 100 descending aortic cine CT images and 108 carotid artery ultrasonography datasets were compared with age and Framingham risk score, respectively. Between 50 and 360 mmHg blood pressures, AWSI variance was 5.43% compared to 64.99% for classical compliance. AWSI correlated better with Framingham risk score and age than conservative wall stiffness evaluation methods. AWSI is a suitable method to evaluate arterial wall properties independent of variable background blood pressure and aortic size effects.