On the Inappropriateness of Non-Invasive Multi-Detector Computed Tomography Coronary Angiography to Trigger off Coronary Revascularization: a comparison with Invasive Angiography

Background Purpose of this prospective study was to evaluate the appropriateness of multi-detector computed tomography angiography (MDCTA) as anatomic standard for decision-making in patients with known or suspected coronary artery disease (CAD). Methods Pressure-derived fractional flow reserve (FFR) was obtained in 81 patients (116 vessels) who underwent both coronary angiogram (CA) and MDCTA. Segments were visually graded for stenosis severity as: G0 = normal, G1 = non-obstructive (<50% diameter reduction), G2 = obstructive (?50% diameter reduction). Results The coronary segments assessed by visual scoring of disease severity were 334. Concordance between segmental severity scores by MDCTA and CA was good (k= 0.74; CI: 0.56 to 0.92). Diagnostic performance of MDCTA for detection of functionally significant stenosis based on FFR was low (sensitivity: 79%; specificity: 64%; positive likelihood ratio: 2.2; negative likelihood ratio: 0.3). Decision-making based on MDCTA would result in revascularization in the absence of ischemia in 22% of patients (18/81) and inappropriate deferral in 7% (6/81), while revascularization in the absence of ischemia would be 16% (13/81) and inappropriate deferral 12% (10/81) with decisions guided by CA. Combined evaluation of stenosis severity using both anatomy (with either CA or MDCTA) and function (with FFR) yields the highest proportion of appropriate decisions: 90 and 91% respectively (p=0.0001 vs CA only, p=0.0001 vs MDCTA only). Conclusions Similar to CA, anatomical assessment of coronary stenosis severity by MDCTA does not reliably predict its functional significance. These findings have important implications regarding the appropriateness of clinical decisions for revascularization.