MedicalResearch.com Interview with:
Dr Christopher Michael Cook MBBS Bsc(Hons) MRCP
MRC Clinical Research Fellow
NHLI, Cardiovascular Medicine, Imperial College London
MedicalResearch.com: What is the background for this study?
Response: FFR-CT is a novel non-invasive technique for estimating the functional significance of a coronary stenosis from CT coronary angiography images. A number of meta-analyses already exist for determining the diagnostic accuracy of FFR-CT (compared to invasive FFR as the reference standard). However, although knowing the overall diagnostic accuracy of FFR-CT is reassuring, in clinical practice a clinician knows not only whether the FFR-CT is positive or negative, but also its actual value. The purpose of this study was to provide clinicians a means of interpreting the diagnostic accuracy of any individual FFR-CT result that may be received in clinical practice.
MedicalResearch.com: What are the main findings?
Response: The main finding of this study is that the diagnostic accuracy of FFR-CT varies markedly across the spectrum of disease. For vessels with FFR-CT above 0.90, 98% met the invasive FFR guideline criterion for deferral. At the other end of the spectrum, for vessels with FFR-CT below 0.60, 86% met the invasive FFR guideline criterion for stenting. However, in between, FFR-CT gives less certainty as to whether the invasive FFR will meet the stenting criterion or not.
MedicalResearch.com: What should readers take away from your report?
Response: Readers can combine the findings of our study with patient specific factors in order to judge when the cost and risk of an invasive angiogram may safely be avoided. Because we now have a more complete picture of what different levels of FFR-CT mean in terms of invasive FFR, it is apparent that a single cut-off value for FFR-CT in deciding on invasive coronary angiography need not always apply. For example, in the asymptomatic patient, further investigations may not be desirable even if an FFR-CT still left a substantial possibility of a positive invasive FFR. Conversely, in the symptomatic patient, the patient and clinician would likely pursue invasive angiography unless the possibility of a positive FFR is very remote.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: This study adopted novel methodology to ascertain the probability that both FFR-CT and invasive FFR agreed on the functional classification of a stenosis, for any given individual FFR-CT value. This type of analysis could be used to determine if further iterative versions of the FFR-CT software translate into improved diagnostic performance, particularly in more intermediate disease severities.
MedicalResearch.com: Is there anything else you would like to add?
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Cook CM, Petraco R, Shun-Shin MJ, Ahmad Y, Nijjer S, Al-Lamee R, Kikuta Y, Shiono Y, Mayet J, Francis DP, Sen S, Davies JE. Diagnostic Accuracy of Computed Tomography–Derived Fractional Flow Reserve A Systematic Review . JAMA Cardiol. Published online May 24, 2017. doi:10.1001/jamacardio.2017.1314
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