The CTCS and CCA were carried out within 1 week. Coronary segments were assessed on CCA following a 17-segment modified American Heart Association (AHA) classification model [14] by a single observer (with more than 10 years’ experience), who was blinded to the CT and clinical data. A mean luminal narrowing of ≥50% was considered to be a significant stenosis. Validated quantitative coronary angiography software (CAAS II®, Pie Medical, Maastricht, the Netherlands) was used.