Clinical Use of CT-Derived Fractional Flow Reserve in the Emergency Department

This study sought to examine the feasibility, safety, clinical outcomes, and costs associated with computed tomography-derived fractional flow reserve (FFR_CT) in acute chest pain (ACP) patients in a coronary computed tomography angiography (CTA)-based triage program.

FFR_CT is useful in determining lesion-specific ischemia in patients with stable ischemic heart disease, but its utility in ACP has not been studied.

ACP patients with no known coronary artery disease undergoing coronary CTA and coronary CTA with FFR_CT were studied. FFR_CT ≤0.80 was considered positive for hemodynamically significant stenosis.

Among 555 patients, 297 underwent coronary CTA and FFR_CT (196 negative, 101 positive), whereas 258 had coronary CTA only. The rejection rate for FFR_CT was 1.6%. At 90 days, there was no difference in major adverse cardiac events (including death, nonfatal myocardial infarction, and unexpected revascularization after the index visit) between the coronary CTA and FFR_CT groups (4.3% vs. 2.7%; p = 0.310). Diagnostic failure, defined as discordance between the coronary CTA or FFR_CT results with invasive findings, did not differ between the groups (1.9% vs. 1.68%; p = NS). No deaths or myocardial infarction occurred with negative FFR_CT when revascularization was deferred. Negative FFR_CT was associated with higher nonobstructive disease on invasive coronary angiography (56.5%) than positive FFR_CT (8.0%) and coronary CTA (22.9%) (p < 0.001). There was no difference in overall costs between the coronary CTA and FFR_CT groups ($8,582 vs. $8,048; p = 0.550).

In ACP, FFR_CT is feasible, with no difference in major adverse cardiac events and costs compared with coronary CTA alone. Deferral of revascularization is safe with negative FFR_CT, which is associated with higher nonobstructive disease on invasive angiography.