Danish Study of Non-Invasive Diagnostic Testing in Coronary Artery Disease 2

CCTA has become the preferred diagnostic modality for symptomatic patients with low to intermediate risk of CAD. Of the patients examined, CCTA exclude cardiovascular disease in 70-80% with an excellent negative predictive value of more than 95%. Having a low positive predictive value, however, CCTA often overestimates the severity of CAD, especially in patients with moderate to severe coronary calcification. Following CCTA, patients are hence unnecessarily tested using golden standard ICA-FFR. These ICAs often show no obstructive coronary stenosis and are therefore not followed by revascularization. The issues outlined raises the question of whether it is possible (1) to make a more precise risk stratification and consequently better selection of patients prior to CCTA and (2) to reduce the number of patients referred for unnecessary ICAs following CCTA.

In patients with suspicion of coronary stenosis detected by CCTA, current guidelines recommend verification of myocardial ischemia. In Dan-NICAD 2, we intend to investigate the diagnostic accuracy of advanced non-invasive myocardial perfusion imaging tests; Rb PET and 3T CMRI. These examinations have shown a high diagnostic accuracy in symptomatic patients with high risk of ischemic heart disease. However, the diagnostic accuracy is not investigated in patients as follow-up after CCTA.

An alternative way to increase the diagnostic accuracy of CCTA and thus avoid unnecessary downstream testing using ICA is to utilize the ability to extract physiological information from the anatomical CCTA images. CT-FFR has in previous studies shown promising results. CT-FFR has not been head to head compared against Rb PET and 3T CMRI.

Obtained during ICA, QFR is a novel wire-free approach for fast computation of FFR with potential to increase the global use of physiological lesion assessment. QFR is superior to traditional assessment of intermediate coronary lesions (ICA-QCA diameter stenosis). However, disagreement between FFR and QFR has been identified in up to 20% of all measurements.

Acoustic detections of coronary stenosis from automatically recorded and analyzed heart sounds is a newly developed technology potentially useful for pre-test risk stratification before e.g. CCTA. One of these devices, the CADScor®System, has previously shown an area under the receiver operating characteristic curve (AUC of ROC) of 70-80% compared to conventional ICA-QCA. This indicates that the CADScor®System could potentially supplement clinical assessment of CAD and be used for risk stratification prior to CCTA.