Implications of imaging modalities on coronary vessel reconstruction and computation of the local hemodynamic forces

Endothelial shear stress (ESS) is an instigator of vulnerable plaque formation and destabilization. Traditionally, their computation is performed in models reconstructed from the fusion of intravascular imaging and angiography. Three-dimensional quantitative coronary angiography (3D-QCA) and computed tomography coronary angiography (CCTA) have emerged as alternative approaches to assess flow patterns, however, there is limited evidence about their performance.

We analysed data from 27 patients (38 vessels) that underwent coronary angiography, CCTA and near-infrared spectroscopy intravascular ultrasound (NIRS-IVUS) imaging. In each vessel, four reconstruction models were generated: 3D-QCA, CCTA and two fusion models - NIRS-IVUS with 3D-QCA (Angio-NIRS-IVUS) and CCTA (CCTA-NIRS-IVUS). In these models, the minimum and maximum predominant ESS were computed in 3 mm segments and the detected lesions, and their estimations were compared using the CCTA-NIRS-IVUS as the reference standard.

In the 3 mm analysis, the Angio-NIRS-IVUS and CCTA estimations had a higher correlation with CCTA-NIRS-IVUS than 3D-QCA for the minimum (intraclass correlation coefficient, ICC: 0.822 vs 0.704 vs 0.581, p < 0.001) and maximum ESS (ICC: 0.852 vs 0.758 vs 0.634, p < 0.001). In lesion-level analysis, only the CCTA-NIRS-IVUS and Angio-NIRS-IVUS (ICC: 0.606, p < 0.001) estimations for the minimum ESS were correlated, while for the maximum ESS, there was a stronger correlation between CCTA-NIRS-IVUS and Angio-NIRS-IVUS and CCTA compared to the 3D QCA (ICC: 0.898 vs 0.836 vs 0.742, p < 0.001).

A strong association was noted for the ESS estimated in the hybrid NIRS-IVUS-based reconstructions with CCTA appearing as the 2nd best modality for assessing the local hemodynamic milieu.