Quantitative coronary angiography of bioresorbable vascular scaffold: A core lab perspective

Invasive quantitative coronary angiography (QCA) is one of the most commonly used methods for the assessment of coronary vessels with bioresorbable scaffolds (BRSs) or metallic stents. The treated segment and the peri-scaffold segments should be analyzed by QCA. In case of polymeric scaffolds, the metallic markers at the proximal and distal ends of the device are the only visible structures for QCA analysis. Several quantitative angiography systems, including the Cardiovascular Angiography Analysis System (CAAS), can perform automated stenosis detection in a given coronary segment. This chapter computes QCA parameters: mean lumen diameter, minimal lumen diameter (MLD), reference vessel diameter (RVD), percentage diameter stenosis, Dmax, lumen area by edge detection and videodensitometry, acute gain, acute recoil, late loss, late luminal gain, net gain, curvature, angulation, and vasomotion. It summarizes definitions and formulas of QCA parameters for assessment of BRSs. The chapter presents the artifactual difference of the impact of radiopaque metallic stents and radiolucent polymeric scaffolds on the QCA assessments.