Long-term prognostic implications of CT angiography-derived fractional flow reserve: Results from the DISCOVER-FLOW study

Abstract

Background & objectives: The long-term prognostic implications of CT angiography-derived fractional flow reserve (FFR_CT) remains unclear. We aimed to explore the long-term outcomes of FFR_CT in the first-in-human study of it.

Materials & methods: A total of 156 vessels from 102 patients with stable coronary artery disease, who underwent coronary CT angiography (CCTA) and invasive FFR measurement, were followed. The primary endpoint was target vessel failure (TVF), including cardiovascular death, target vessel myocardial infarction, and target vessel revascularization. Outcome analysis with FFR_CT was performed on a per-vessel basis using a marginal Cox proportional hazard model.

Results: During median 9.9 years of follow-up, TVF occurred in 20 (12.8%) vessels. FFR_CT ​≤0.80 discriminated TVF (hazard ratio [HR] 2.61, 95% confidence interval [CI] 1.06, 6.45). Among 94 vessels with deferral of percutaneous coronary intervention (PCI), TVF risk was inversely correlated with FFR_CT ​(HR 0.62 per 0.1 increase, 95% CI 0.44, 0.86), with the cumulative incidence of TVF being 2.6%, 15.2%, and 28.6% for vessels with FFR_CT ​>0.90, 0.81-0.90, and ≤0.80, respectively (p-for-trend 0.005). Predictive value for clinical outcomes of FFR_CT was similar to that of invasive FFR (c-index 0.79 vs 0.71, P ​= ​0.28). The estimated TVF risk was higher in the deferral of PCI group than the PCI group for vessels with FFR_CT ≤0.81.

Conclusion: FFR_CT showed improved long-term risk stratification and displayed a risk continuum similar to invasive FFR.

Clinical trial registration: NCT01189331.

Keywords: Coronary CT angiography; Fractional flow reserve; Long-term outcome; Non-invasive imaging; Risk stratification.