Intimal thickening sourced from low wall shear stress in human left coronary artery was observed by optical coherence tomography

The high resolution of optical coherence tomography (OCT) may offer improved description of luminal surfaces and intimal thickening in human coronary arteries by comparison to other imaging modalities, such as intravascular ultrasound (IVUS). We investigated the left anterior descending (LAD) coronary artery of a patient using both OCT and IVUS methods and found an asymmetrical distribution of intimal thickness (IT) around the lumen circumference in the OCT images, whereas the IVUS images showed a lumen with no asymmetry in IT. We reconstructed a 3D coronary artery model from the OCT slices that represented the morphological details of local luminal surfaces accurately and used this to simulate the pulsatile flow field in the model employing computational fluid dynamics (CFD). The pulsatile wall shear stress (WSS) distribution on the LAD surface was derived, and time-averaged WSS was computed. The data for IT and WSS distributions in the LAD segment were compared, and a linear inverse relationship between IT and WSS was found; higher WSS (> 25±5 dynes per square centimeter) favors thinner intima (< 0.12±0.05 millimeters) and lower WSS (< 12±5 dynes per square centimeter) favors thicker intima (> 0.33±0.05 millimeters). The enhanced spatial resolution of OCT offers an improved imaging technique for developing CFD models and assessing early atherosclerosis in patients with coronary artery disease.