One-step anatomic and function testing by cardiac CT versus second-line functional testing in symptomatic patients with coronary artery stenosis: head-to-head comparison of CT-derived fractional flow reserve and myocardial perfusion imaging.

AIMS CT-QFR is a novel coronary computed tomography angiography (CTA) based method for on-site evaluation of patients with suspected obstructive coronary artery disease (CAD). We compared the diagnostic performance of CT-QFR with myocardial perfusion scintigraphy (MPS) and cardiovascular magnetic resonance (CMR) as second-line tests in patients with suspected obstructive CAD after coronary CTA. METHODS AND RESULTS Paired analysis of CT-QFR and MPS or CMR, with an invasive FFR-based classification as reference standard. Symptomatic patients with >50% diameter stenosis on coronary CTA were randomized to MPS or CMR and referred for invasive coronary angiography. The rate of coronary CTA not feasible for CT-QFR analysis was 17%. Paired patient-level data were available for 118 patients in the MPS group and 113 in the CMR group, respectively. Patient-level diagnostic accuracy was better for CT-QFR than for both MPS ((82.2% (95%CI 75.2-89.2) vs. 70.3% (95%CI 62.0-78.7), p=0.029) and CMR ((77.0% (95%CI 69.1-84.9) vs. 65.5% (95%CI 56.6-74.4), p=0.047). Following a positive coronary CTA and with the intention-to diagnose, CT-QFR, CMR and MPS were equally suitable as rule-in and rule-out modalities. CONCLUSIONS The diagnostic performance of CT-QFR as second-line test was at least similar to MPS and CMR for the evaluation of obstructive coronary artery disease in symptomatic patients presenting with ≥50% diameter stenosis on coronary CTA.