CT-Derived FFR Could Improve Efficiency of Referral to ICA

For patients with chest pain referred for invasive coronary angiography (ICA), the addition of fractional flow reserve derived from coronary CT angiography (FFR_CT) results in better prediction of revascularization and events, according to data from an observational cohort study of patients in the PROMISE trial. 

 “FFRCT has the potential to improve efficiency of referral to ICA,” said Michael T. Lu, MD, of Massachusetts General Hospital, Boston, Mass. “The study showed FFRCT is closely associated with observed clinical management, revascularization and events.”

The observational cohort study focused on 131 patients with FFRCT  ≤ 0.80 and 50 patients with FFRCT ≥ 0.80.

“We defined a per-patient positive test for severe stenosis and FFRCT ≤ 0.80. We compared [degree of stenosis by] CTA and ICA, and then looked at hazard ratios for composite revascularization or events and estimated the efficiency of FFRCT as a gatekeeper to ICA, defined as a percent of ICA leading to revascularization,” Lu said. 

FFRCT ≤ 0.80 better predicted revascularization and events than CTA stenosis ≥ 70% (Figure), and the use of FFRCT ≤ 0.80 as a gatekeeper to angiography was predicted by Lu to “increase the percentage of ICA leading to PCI from 49% to 61%.” 

Lu cited several limitations of the analysis, including that it only involved patients with nitroglycerin during CTA. One-third of eligible CTAs could not be evaluated with FFRCT, compared with 13% in the NXT trial and 12% in the PLATFORM trial. Additionally, site reads were utilized for CTA and ICA, while blinded core reads were utilized for FFRCT. 

Disclosures:

• Lu reports receiving research support from HeartFlow.