Fractional flow reserve derived from coronary computed tomography angiography reclassification rate using value distal to lesion compared to lowest value.

Introduction: A standardised approach to the interpretation of FFRCT data is currently lacking. We evaluated the rate of reclassification of FFRCT positivity using the FFRCT value distal to an anatomical stenoses compared to the lowest FFRCT value.

Method: Patients who underwent coronary CTA and FFRCT analysis were eligible. FFRCT value of ≤ 0.80 was considered positive. Positive FFRCT distal to stenosis was defined as those with a stenoses of ≥ 25% with an associated FFRCT value of ≤ 0.80 within 2cm distal to the lesion. Outcome data on subsequent invasive coronary angiography (ICA) and coronary revascularisation were collected with a minimum follow-up of 60 days to account for delay between referral for invasive testing and/or revascularisation and receiving the procedure.

Result: 192 patients (mean age 60.7 ± 10.6 years, 67.5% men) were included. FFRCT was positive for lowest FFRCT value in 55.7% of patients. Positive FFRCT value distal to stenosis was found in 31.3%. The overall reclassification rate of those positive for lowest FFRCT value to negative for FFRCT value distal to stenosis was 43.9% (p < 0.01). The reclassification rates were most pronounced for those with intermediate stenoses - 67% for those with < 50% stenoses, p < 0.01; 49% for 50-69% stenoses, p < 0.01. Amongst those who underwent ICA, the rate of revascularization was significant higher for those with positive FFRCT distal to stenosis compared to those positive for lowest FFRCT value (revascularization/ICA = 0.53 vs 0.44, p < 0.01).

Conclusion: Using FFRCT values distal to a anatomical stenoses, 44% of patients positive for lowest FFRCT value were reclassified as negative for FFRCT value distal to stenosis. Those who underwent ICA, the rate of revascularisation was higher amongst those with positive FFRCT distal to stenosis compared to those positive for lowest FFRCT value.