Introduction of The Anatomic–Functional Duality of So-called ‘Significant’ Atherosclerotic Stenosis – Update on Invasive Diagnostic Strategies in Coronaropathy

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Summary

“Nothing comes to us except falsified and altered by our senses.”
Michel de Montaigne (1533–1592)

Coronary angiography (CA) has been performed in cardiology centres for more than 50 years. The diagnosis it provides soon became the gold standard in coronaropathy. It is a purely anatomic diagnosis, and this approach has made a deep mark on cardiology, although the need for a prior non-invasive functional approach was quickly admitted and developed.^1,2 Nevertheless, our view of the functional impact of coronary stenosis was quickly reduced to a hypothetico-deductive inference drawn from a simple morphological index. So-called ‘significant’ atherosclerotic coronary stenosis is defined by a simple binary morphological index of tightness – percent diameter stenosis (%DS >50 %) – to which the most recent guidelines on myocardial revascularisation still refer for clinical decision-making.³ A ‘stenosis’ is visualised as a pathological focal anatomic entity on imaging, and its functional impact on myocardial perfusion (i.e. its significance) is then, still to the present day, inferred by a process of hypothetico-deductive reasoning.

Interventional cardiologists presently dispose of at least three complementary techniques supplementing CA: intravascular ultrasound (IVUS) and optical coherence tomography (OCT), and pressure guide to determine fractional flow reserve (FFR). The present update seeks to:

• define the ambiguous relationship between functional impact and morphology in atherosclerotic coronary stenosis;
• specify the means of invasive diagnosis, both anatomical and functional, complementing CA in order to compensate for the anatomic and functional limitations intrinsic to the latter; and
• bring these preliminary considerations to bear on the design of different diagnostic exploration strategies in interventional cardiology.