AimsIn symptomatic patients with suspected coronary artery disease (CAD), computed tomographic angiography (CTA) improves patient selection for invasive coronary angiography (ICA) compared with functional testing. The impact of measuring fractional flow reserve by CTA (FFRCT) is unknown.Methods and resultsAt 11 sites, 584 patients with new onset chest pain were prospectively assigned to receive either usual testing (n = 287) or CTA/FFRCT (n = 297). Test interpretation and care decisions were made by the clinical care team. The primary endpoint was the percentage of those with planned ICA in whom no significant obstructive CAD (no stenosis ≥50% by core laboratory quantitative analysis or invasive FFR < 0.80) was found at ICA within 90 days. Secondary endpoints including death, myocardial infarction, and unplanned revascularization were independently and blindly adjudicated. Subjects averaged 61 ± 11 years of age, 40% were female, and the mean pre-test probability of obstructive CAD was 49 ± 17%. Among those with intended ICA (FFRCT-guided = 193; usual care = 187), no obstructive CAD was found at ICA in 24 (12%) in the CTA/FFRCT arm and 137 (73%) in the usual care arm (risk difference 61%, 95% confidence interval 53–69, P< 0.0001), with similar mean cumulative radiation exposure (9.9 vs. 9.4 mSv, P = 0.20). Invasive coronary angiography was cancelled in 61% after receiving CTA/FFRCT results. Among those with intended non-invasive testing, the rates of finding no obstructive CAD at ICA were 13% (CTA/FFRCT) and 6% (usual care; P = 0.95). Clinical event rates within 90 days were low in usual care and CTA/FFRCT arms.ConclusionsComputed tomographic angiography/fractional flow reserve by CTA was a feasible and safe alternative to ICA and was associated with a significantly lower rate of invasive angiography showing no obstructive CAD.

In patients with stable chest pain and planned invasive coronary angiography, care guided by CTA and selective FFRCT was associated with equivalent clinical outcomes and QOL, and lower costs, compared with usual care over 1-year follow-up. (The PLATFORM Study: Prospective LongitudinAl Trial of FFRct: Outcome and Resource IMpacts [PLATFORM]; NCT01943903).

An evaluation strategy based on FFRCT was associated with less resource use and lower costs within 90 days than evaluation with invasive coronary angiography. Evaluation with FFRCT was associated with greater improvement in quality of life than evaluation with usual noninvasive testing. (Prospective Longitudinal Trial of FFRCT: Outcomes and Resource Impacts [PLATFORM]; NCT01943903).

Patients with a low V/M ratio have lower FFR overall and in non-obstructive CAD, independent of plaque measures.

The diagnostic performance of FFR for staged detection of ischemia in STEMI patients with multivessel disease is moderate. STEMI patients have a smaller vessel volume than do patients with stable angina. The diagnostic performance of FFR is influenced by the volume-to-mass ratio. This study does not support routine use of FFR in the post-STEMI setting. (Assessment of Coronary Stenoses Using Coronary CT-Angiography and Noninvasive Fractional Flow Reserve; NCT01739075).