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The authors (Nazir et al) of the review of CT fractional flow reserve published in Heart are to be congratulated on very well balanced and well written review of this relatively new technology (1).
We would like to raise a couple of points regarding imaging stress tests functioning as a gatekeeper to invasive coronary angiography after a stenosis is identified on CTCA. A recent survey of UK cardiologists identified imaging stress tests as the most common approach to assess the functional significance of a moderate stenosis (50-70%) on CTCA, with only 2% electing to use CT-FFR (2). The current increase in the use of CT-FFR is because it is nationally funded. Importantly, stress echocardiography is a very low cost test with a national tariff of £177, which compares favourably with the new reduced tariff for CT-FFR of £530. With time, this may be re-balance in favour of CT-FFR if the tariff drops further, particularly given the attraction of a single patient episode and with an anticipated growth of cardiac CT in line with NICE recommendations.
It is important to remind readers that the PLATFORM (3) trial compared CTCA plus CT-FFR versus the standard of care in patients with stable chest pain. The patients were divided into an invasive sub-study (n=380) and a non-invasive sub-study (n=204) and the end point of the study was reduction of invasive coronary angiography that showed no obstructive CAD. In the non-invasive sub-study there was no difference in the r...
It is important to remind readers that the PLATFORM (3) trial compared CTCA plus CT-FFR versus the standard of care in patients with stable chest pain. The patients were divided into an invasive sub-study (n=380) and a non-invasive sub-study (n=204) and the end point of the study was reduction of invasive coronary angiography that showed no obstructive CAD. In the non-invasive sub-study there was no difference in the rate of invasive coronary angiography between imaging stress tests and CTCA plus CT-FFR. In the invasive sub-study, CTCA plus CT-FFR reduced the rate of invasive coronary angiography as only patients found to have significant stenosis on CTCA and positive CT-FFR went on to have an invasive coronary angiogram, while in the invasive arm all patients had to undergo invasive coronary angiogram ± invasive FFR.
Finally, the ISCHAEMIA trial (4) would suggest that following CT assessment of the coronary arteries and exclusion of left main stem disease, further investigation to assess significance of coronary stenoses is not necessarily required should symptoms be controlled on optimal medical therapy.
1. Nazir MS, Mittal TK, Weir-McCall J, et al Opportunities and challenges of implementing computed tomography fractional flow reserve into clinical practice Heart Published Online First: 19 June 2020. doi: 10.1136/heartjnl-2019-315607
2. Fyyaz S, Papachristidis A, Byrne J, Alfakih K. Opinions on the expanding role of CTCA in patients with stable chest pain and beyond: a UK survey. The British Journal of Cardiology. 2018;25:107-9 doi: 10.5837/bjc.2018.019
3. Hlatky MA, De Bruyne B, Pontone G, et al. PLATFORM Investigators. Quality-of-Life and Economic Outcomes of Assessing Fractional Flow Reserve With Computed Tomography Angiography: PLATFORM. J Am Coll Cardiol 2015;66:2315-2323.
4. Maron DJ, Hochman JS, Reynolds HR, Bangalore S, O’Brien SM, Boden WE, et al. Initial Invasive or Conservative Strategy for Stable Coronary Disease. New England Journal of Medicine. 2020.