Introduction on The Role of Bioresorbable Scaffolds in Meeting the Challenges of Bifurcations
It is estimated that 15-20 % of all coronary interventional procedures involve side branches.1 Side branches are frequently related to periprocedural complications. Side branch occlusion or compromise appears to be the underlying cause of approximately 30 % of periprocedural myocardial infarctions.2 Periprocedural infarction in turn is an important predictor of midterm mortality3. Considering any side branches >1 millimetres (mm), clinical studies including complex lesions in the modern drug-eluting stent (DES) era have demonstrated side branch occlusion or reduced flow in approximately 10 % of interventional procedures.2
The above noted does not comprise the left main bifurcation, which can also be regarded as a side branch anatomy. Significant left main disease is observed in 3-5 % of patients undergoing coronary angiography.4 Increasingly, interventional procedures are considered an alternative to surgical revascularisation in unprotected left main disease. As a result of the fast-evolving technical advances, it is impossible to obtain a durable appraisal of the interventional techniques compared with surgery. Yet, recent data suggest interventional left main procedures can markedly improve patient outcome compared with medical treatment.5
The Medina classification is used to describe the distribution of stenoses between main vessel and side branch in the bifurcation lesion.6 In short, a stenosis can affect the proximal portion of the main vessel (proximal to the side branch) or its distal portion, or it can affect the side branch itself. Combinations of either two of these locations are possible as well as stenoses in all three locations. For example, a lesion with stenoses pertaining to the proximal as well as the distal portion of the main vessel, but sparing the side branch, is classified as Medina (1,1,0).