Tutorial | Part 1: Definitions


A bifurcation is a division of a main, parent, branch into two daughter branches of at least 1.5mm. Bifurcation lesions may involve the proximal main vessel, the distal main vessel and the side branch according to the Medina classification. The smaller of the two daughter branches should be designated as the ‘side branch’. In case of the main stem either the LCX or the LAD can be designated as the side branch depending on their respective calibres. Bifurcations are only scored for the following segment junctions: 5/6/11, 6/7/9, 7/8/10, 11/13/12a, 13/14/14a, 3/4/16 and 13/14/15.

Bifurcation (Medina) is classified when 50% lumen narrowing occurs within 3 mm of the bifurcation point. Bifurcations are only scored for existing SYNTAX Score segments, i.e. segments that have a segment number. In other words, bifurcation lesions within side branches of the intermediate branch, the diagonal branch, the obtuse marginal branch and the posterolateral branch are considered as bifurcation of second order and not scored.

Example 1

  • One lesion 
  • One segment number involved/diseased (= segment: 7)
  • Bifurcation ‘Yes’ 
  • Medina class: 0, 1, 0 

Example 2

  • One lesion
  • Three segment numbers involved/diseased (= segments: 6, 7 and 9)
  • Bifurcation ‘Yes’
  • Medina class: 1, 1, 1