Coronary CT angiography (CCTA) is used as a triage test before invasive coronary angiography (ICA). In this study we assessed the level of agreement between the two methods in patients whose CCTA reported severe stenosis in the presence of a low coronary artery calcium (CAC) score. We retrospectively analyzed 124 patients selected from a total of 2,742 examinations who underwent both CCTA and ICA. A discordant group (n=33) had stenosis reported on CCTA together with a low CAC (<400 and <100 AU). Across the whole cohort, obstructive disease (≥50% in the left main coronary artery or ≥70% in the other segments) was present in 44.4% of patients. In the discordant subgroup, agreement between CCTA and ICA was markedly worse: ICA showed obstructive disease in only 6.1% of patients. These results suggest that, although CAC remains a stand-alone predictor of obstructive disease, its predictive value is limited in a population already selected by referral for catheterization. The substantial discrepancy observed in cases where CCTA reports severe disease in the presence of a low CAC score raises the possibility that CCTA overestimates stenosis severity. In patients showing this pattern of discordance, non-invasive functional testing before referral to ICA could therefore be useful.
Coronary CT angiography is a non-invasive method of analyzing the coronary lumen through which the atheromatous bur-den can be evaluated, with the analysis of the type of plaque (soft, calcified, mixed) and the impact on the arterial lumen (stenosis, occlusion). The anatomical evaluation by coronary CT is indicated in symptomatic patients with low and medium risk factors for coronary atherosclerotic disease, in those with inconclusive laboratory and EKG results, patients with un-certain stress test results, in the evaluation of coronary grafts and intrastent stenoses. Depending on the result of the angiography, the severity of the stenosis and the management of the patient are established. In the case of mild and medium stenoses, risk factors management and drug treatment are recommended. For severe stenoses, patients are referred for interventional coronary angiography or functional evaluation. Coronary CT angiography increases the certainty of coronary atherosclerotic disease diagnosis. It has a superior discriminative capacity of plaques with low attenuation, the main predictor of myocardial infarction, with almost five-fold higher risk. Coronary CT angiography increases the adaptation of medication, and the inclusion of statin therapy decreases the risk of fatal and nonfatal myocardial infarction at 5 years and increases the quality of life.
