Abstract Background Coronary computed tomography angiography (CCTA) has been expanded as a tool for non-invasive assessment of coronary artery disease. In the past, it was standard practice to undergo the invasive fractional flow reserve (FFR) to determine the indication of coronary revascularization, however, recently it has become common to perform FFR derived from CCTA (FFR-CT) first. Previous reports demonstrated that the relationship between invasive FFR and coronary calcium score (CCS), however, little is known that the relationship between FFR-CT and CCS per vessels. We aimed to evaluate that relationship and usefulness in the consecutive patients who underwent CCTA and FFR-CT. Methods A total of 102 consecutive patients who underwent CCTA in our hospital was included in this study. The vessels with previous culprit of myocardial infarction and inability to calculate the value of FFR-CT because of artifact, previous stent deployment, and narrow vessel diameters were excluded. Finally, 87 of right coronary artery (RCA), 86 of left anterior descending artery (LAD), and 92 of left circumflex artery (LCX) were eligible for analysis in this study. FFR-CT value of 0.80 or less was defined as positive for myocardial ischemia. CCS was calculated as an Agaston Score per vessels. At that time, LAD and LCX were both included left main trunk. Results Mean CCS were 262.3±449.4 in RCA, 380.0±538.1 in LAD, and 177.1±298.2 in LCX, respectively. Mean FFR-CT were 0.89±0.10 in RCA, 0.77±0.12 in LAD, and 0.88±0.10 in LCX, respectively. Receiver operating characteristic (ROC) curve demonstrated the cut-off value to determine myocardial ischemia using CCS of RCA, LAD, and LCX were 182.2 (p=0.0009, AUC=0.89), 187.0(p=0.0003, AUC=0.74), and 209.6(p=0.0156, AUC=0.66), respectively. The cut-off value of RCA showed high negative predictive value negative predictive value (NPV) of 100%, on the other hand, those of LAD and LCX showed moderate NPV of 76% and 90%. Conclusions CCS had a significant correlation with FFR-CT and useful for deferral strategy without invasive examination, especially in RCA.Diagnostic performance of CCS
Takami et al. (Thu,) studied this question.