A multi-artery Fractional Flow Reserve (FFR) approach for handling coronary stenosis–stenosis interaction in the multi-vessel disease (MVD) arena

Abstract

BackgroundFFR is a widely accepted ‘gold standard’ of coronary stenosis severity indices in MVD cases. Contrary to this conception, reality shows that true FFR values that are equal to the real fractional remnant blood flow exist only in single vessel disease (SVD) cases and in those MVD cases that are decomposable into independent SVD cases. ObjectivesThe article is firstly aimed at defining the limits of validity of the basic single-artery FFR index. It is then intended to devise an FFR method for handling MVD cases in the presence of stenosis–stenosis interaction. MethodsThe boundaries of the frame of validity of single-artery true FFR are determined. A detailed multi-artery FFR analysis of the effect of stenosis–stenosis interaction in an MVD scenario consisting of stenotic LM and LAD arteries and a non-stenotic LCx artery is subsequently developed. ResultsThe multi-artery FFR approach developed in the article demonstrates handling a 3-artery configuration like LM–LAD–LCx. The method takes into account the effect of all the stenoses and yields quantitative guidelines for the practitioner that lead to optimal treatment that accommodates each artery. Calculations are also in agreement with the effect of stenosis–stenosis interaction on FFR(LM) reported in the literature. ConclusionsIt turns out that the basic single-artery FFR approach cannot handle MVD cases that involve stenosis–stenosis interaction like concomitantly stenotic LM artery and LAD (or LCx) artery. In the multi-artery FFR approach the various ratios of intracoronary pressures lose their original single-artery FFR meaning and the revascularization criteria change.