The Value of CT Fractional Flow Reserve

Coronary Computed Tomography Angiogram (CCTA) is a non-invasive imaging modality that has high sensitivity and negative predictive value for the detection of coronary artery disease (CAD). The main limitations of CCTA are its poor specificity and positive predictive value, as well as its inherent lack of physiologically relevant data on hemodynamic significance of coronary stenosis, a data that is provided either by non-invasive stress tests such as myocardial perfusion imaging (MPI) or invasively by measurement of the Fractional Flow Reserve (FFR). Recent advances in computational fluid dynamic techniques applied to standard CCTA are now emerging as powerful tools for virtual measurement of FFR from CCTA imaging (CT-FFR). These techniques correlate well with invasively measured FFR [1-4]. The primary purpose of this study is to evaluate the incremental benefit CT-FFR as compared to CCTA in triaging chest pain patients in outpatient settings who are found to have obstructive CAD upon CCTA (> 30% and < 90% stenosis). Invasive FFR and short term clinical outcomes (90 days) will be correlated with each diagnostic modality in order to evaluate positive and negative predictive value of each when used incrementally with CCTA. This will be an observational trial in which patients will undergo a CCTA, as part of routine care. If the patient consents to participate in the study and is found to have coronary stenosis of 30% to 90%, based on the cardiologist's reading, the CCTA study will be sent to HeartFlow, a vendor that will provide a computerized FFR reading, based on the CCTA study. If the noninvasive FFR diagnosis indicates obstructive disease, the patient will be recommended to undergo cardiac catheterization with invasive FFR. As CCTA utilization increases, the need to train additional imaging specialists will increase. This study will assess the capability of FFR-CT to enhance performance on both negative and positive predictive value for less experienced readers by providing feedback based on CT-FFR evaluation. CCTA readers will be grouped in two categories: those with more than 10 years reading experience and those with less than 10 years reading experience. Each CCTA will be read by a less experienced and a more experienced reader. Results from each reader will be correlated with each other and with the CT-FFR and invasive FFR results.