Correlation of Fractional Flow Reserve with non-invasive tests for the detection of ischaemia due to intermediate coronary artery stenosis
Journal of Cardiovascular Magnetic Resonance volume 13, Article number: P85 (2011)
To compare ischaemia assessment by Fractional flow reserve (FFR) with non-invasive testing in patients with intermediate coronary artery stenosis.
FFR was initially validated against SPECT, Dobutamine Stress Echo and Exercise Testing . It is now frequently used to determine the management of intermediate coronary artery stenosis. A cut-off value of 0.75 is used in clinical practice to guide revascularisation supported by long-term outcome data , but a ‘grey zone’ of 0.75-0.8 with uncertain clinical significance exists . Advances in non-invasive imaging tests (gated SPECT and CMR) warrant a re-evaluation of FFR at intermediate stenosis severity against non-invasive imaging.
Patients due for investigation of presumed cardiac chest pain were recruited and underwent SPECT (Discovery, GE Healthcare), perfusion-CMR (1.5T, Intera, Phillips) and coronary angiography. Any vessel that was angiographically determined as intermediate severity (40-70%) was assessed by QCA and pressure wire-derived FFR (RADI medical systems, Uppsala, Sweden).
In 23 study patients (age 57±8, 78% male), 33 FFR measurements were performed (LAD 64%, Cx 18%, RCA 12%, LMS 6%). FFR was classified negative (>0.80) in n=20. Perfusion-CMR detected ischaemia in 3 vessels (2 with positive FFR and one with 'grey' FFR). SPECT also detected ischaemia in 3 vessels (2 negative FFR and one positive FFR), (Table 1). Coronary stenosis by QCA and FFR correlated poorly (r= -0.35, p=0.054) . Chi-squared analysis of FFR severity found no significant association between FFR positivity and perfusion-CMR (p=0.078) or SPECT (p=0.34).
Non-invasive imaging does not correlate well with FFR measurements in intermediate coronary lesions. Perfusion-CMR whilst not significantly discriminating between the groups had no false negatives and may thus be the more useful additional test to determine the significance of ‘grey’ lesions on FFR.
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Fairbairn, T.A., Mather, A., Greenwood, J. et al. Correlation of Fractional Flow Reserve with non-invasive tests for the detection of ischaemia due to intermediate coronary artery stenosis. J Cardiovasc Magn Reson 13 (Suppl 1), P85 (2011). https://doi.org/10.1186/1532-429X-13-S1-P85
- Fractional Flow Reserve
- Coronary Stenosis
- Dobutamine Stress
- Grey Zone