Clinical expert consensus document on quantitative coronary angiography from the Japanese Association of Cardiovascular Intervention and Therapeutics

Fig. 1. History of quantitative coronary angiography. Quantitative coronary angiography (QCA) originated from the basic concept of showing objective numerical data in addition to a visual assessment. The emergence of metallic stents and drug-eluting stents has further increased its utility. As shown by the number of articles available in PubMed, even after the introduction of intravascular imaging and fractional flow reserve, QCA has maintained its value by applying three-dimensional QCA technology. FFR fractional flow reserve, PCI percutaneous coronary intervention

Fig. 2. Standard scheme of measurement data. PCI percutaneous coronary intervention

Fig. 3. A representative case of diffuse lesion. When the automated obstruction length and reference diameter are too underestimated at baseline, appropriate correction of the lesion length should be considered. When the in-stent restenosis appears proximally on diffuse lesion, the value of late lumen loss is usually unremarkable, whereas the diameter of stenosis is prominent. This discrepancy is so-called the previously reported “relocation” of the minimal lumen diameter. MLD minimal lumen diameter, RD reference diameter, DS diameter stenosis

Fig. 4. An example of total occlusive lesion. RD reference diameter, DS diameter stenosis

Fig. 5. Bifurcation analyses using bifurcation-dedicated algorithms on a QAngio® XA and b CAAS®

Fig. 6. Subsegments defined using bifurcation-dedicated algorithms on a QAngio® XA and b CAAS®. a QAngio® XA provides two different bifurcation analysis models (T-shape model and Y-shape model) that are applied according to the morphology of the bifurcation. b CAAS® reports two different segment models (6- and 11-segment model). POC polygon of confluence

Fig. 7. Quantitative flow ratio on QAngio® XA. The quantitative flow ratio (QFR) is computed based on three-dimensional angiography reconstructed from two different projections with angles ≥ 25° apart and volumetric flow rate calculated using a contrast bolus frame count. The QFR reports virtual color-coded pullbacks of FFR of the arteries with stenosis for which angiography were performed, without the use of a pressure wire or hyperemia