Purpose: The aim of this study was to investigate the individual and combined accuracy of Dynamic Stress CTP and FFRct for the identification of functionally relevant CAD.
Methods: 85 patients (n: 67 men, mean age 65 years) with intermediate-to-high pretest likelihood of CAD, and planned for invasive coronary angiography (ICA) plus invasive FFR, underwent cCTA imaging and Dynamic stress CTP during adenosine vasodilation. FFRct was computed and a patient-specific myocardial blood flow index was calculated. Using binary regression, diagnostic performance of cCTA alone, cCTA+FFRct, cCTA+CTP or cCTA+FFRct+CTP were evaluated using C statistics versus invasive FFR, with a threshold of 0.80 as a reference.
Results: cCTA alone reached the highest sensitivity (83%) with significant improvement of specificity, positive predictive value and overall accuracy with both FFRct or CTP on top of cCTA. With binary logistic regression, the sequential strategy based with cCTA+FFRct+CTP reached the highest AUC for both vessel-based analysis (0.91) and patient-based analysis (0.91).
Conclusions: Stress dynamic CTP and FFRct both identify functionally significant CAD, with comparable accuracy. Diagnostic performance can be improved by combining the two techniques; a stepwise approach, reserving stress dynamic CTP for intermediate FFRct results, improves diagnostic performance while omitting the majority of the population from Dynamic Stress CTP examination.