Relation of angiographic side branch calibre to myocardial mass: a proof of concept myocardial infarct index.

Elevation of biomarkers and ischaemia after coronary stenting of a bifurcation is not uncommon due to side branch (SB) occlusion. Hence, it is important to understand the relation between the lumen calibre of the SB and the myocardial mass affected. The objective of this proof of concept perspective is to provide a formulation for the relation between the SB calibre and perfused myocardial mass based on experimentally-validated scaling laws. A lumen calibre-mass scaling law provides a nearly linear relation between cross-sectional area of SB and the myocardial mass at risk. It is clinically known that the larger the diameter of the SB the more myocardial mass is at risk. The present analysis formulates this notion quantitatively and provides a simple relation where the %infarct can be determined directly from the angiographic cross-sectional area of SB. This relation can help guide the decision for bifurcation stenting where the SB may be at risk for occlusion. This brief proof of concept perspective provides a basis for future human studies that may demarcate the calibre (and hence myocardial mass) in relation to cardiac biomarkers as a cut-off for treatment of SB.