Incremental value of computed tomography angiographic derived fractional flow reserve in patients with stable chest pain and anatomical obstructive coronary artery disease

Funding Acknowledgements Type of funding sources: None. Background Coronary computed tomography angiography (CCTA)-derived fractional flow reserve (FFRCT) is endorsed by guidelines for the evaluation of obstructive coronary artery disease (OCAD) (1). However, real-world impact of selective use of FFRCT in patients with suspected OCAD by CCTA on subsequent invasive coronary angiography (ICA) and revascularization remains unclear. Purpose To assess the impact and diagnostic accuracy of FFRCT interpretation in patients with suspected OCAD by CCTA on downstream ICA and revascularization. Methods All consecutive patients who underwent coronary CCTA for the evaluation of stable chest pain between 01/10/2013 and 28/05/2021 in our tertiary university hospital were included in a registry. From a total population of 7541 patients, 1601 with reported anatomical obstructive OCAD on CCTA, were included in our study. OCAD was defined as the presence of a stenosis ≥ 50% in at least one of the three main vessels. CCTA were selectively send to FFRCT analysis according to radiologist's decision. A numerical interpretation of FFRCT was firstly performed by defining a lowest distal value≤ 0.8 as a possible need for revascularization and secondly, a comprehensive interpretation of FFRCT was completed by an experienced interventional cardiologist and radiologist. In brief, this interpretation takes into account not only the lowest distal FFRCT value, but also the post-stenotic FFR, the trans-lesional gradient and anatomical distribution of FFRCT changes. Results From a registry of 7541 patients, suspected OCAD derived from CCTA was reported in 1601 cases, including 808 (50.5%) patients evaluated by FFRCT. ICA was performed in 1160 (72.5%) and revascularization in 559 (34.9%) patients. Overall proportion of ICA decreased from 77.2 to 67.8% with FFRCT use (chi² p<0.01) (Figure 1). After propensity score weighting, FFRCT use was independently associated with decreased ICA (OR: 0.66; 95% CI 0.53–0.83, p< 0.001) and with a decreased rate of myocardial revascularization (OR: 0.71; 95% CI 0.58 –0.88, p< 0.01). Compared to a numerical interpretation, a comprehensive assessment of FFRCT increased the ratio of revascularization per ICA (61.8 vs 50.2 %, p< 0.01) and was more accurate to rule-in OCAD patient requiring a myocardial revascularization (Figure 2). After propensity score adjustment, numerically abnormal FFRCT and pathological coronary disease distribution on comprehensive assessment similar were still independently associated with an increased the rate of ICA use (OR:3.03 95% CI 2.18–4.23, p< 0.001 and OR: 3.45; 95% CI 2.47–4.82, p< 0.001, respectively) and myocardial revascularization (OR:5.13; 95% CI 3.23–8.15, p< 0.001 and OR:6.48; 95% CI 4.55–9.22, p< 0.001, respectively). Conclusion We observed in a large single-center real-world registry that implementing FFRCT downstream ICA and that a comprehensive assessment of FFRCT ensures an improved selection of patients requiring myocardial revascularization.