Radial wall strain: a novel angiographic measure of plaque composition and vulnerability

The lipid-to-cap ratio (LCR) and thin-cap fibroatheroma (TCFA) derived from optical coherence tomography (OCT) are indicative of plaque vulnerability. We aimed to explore the association of a novel method to estimate radial wall strain (RWS) from angiography with plaque composition and features of vulnerability assessed by OCT. Anonymised data from patients with intermediate stenosis who underwent coronary angiography (CAG) and OCT were analysed in a core laboratory. Angiography-derived RWS was computed as the maximum deformation of lumen diameter throughout the cardiac cycle, expressed as a percentage of the largest lumen diameter. The LCR and TCFA were automatically determined on OCT images by a recently validated algorithm based on artificial intelligence. OCT and CAG images from 114 patients (124 vessels) were analysed. The average time for the analysis of RWS was 57 (39-82) seconds. The RWS in the interrogated plaques was 12% (10-15%) and correlated positively with the LCR (r=0.584; p