The difference between a coronary bifurcation lesion and an ordinary lesion lies in the presence of a side branch (SB). Such branches are particularly instrumental in the development of atheroma because of local blood flow patterns and are also a predictive factor of peri-procedural myocardial infarction (MI) when percutaneous coronary angioplasty (PCI) is performed.
The clinical importance of a SB depends on its diameter which is strongly correlated with its flow and the muscular mass that it vascularizes; the diameter of the SB, main branch (MB), and of proximal segment of the MB are indeed interdependent as evidenced by Murray’s law. Therefore, a coronary bifurcation should be divided into three segments, each with its own reference diameter.
Before the advent of coronary stenting, and later with bare-metal stents (BMS), PCI of coronary bifurcation lesions was associated with a lower success rate, a higher risk of complications, and a higher restenosis rate compared to non-bifurcation lesions. Although the use of drug-eluting stents (DES) has resulted in reduced restenosis rates and reintervention, coronary bifurcation lesions remain a higher risk setting especially when the bifurcation is proximal.
Over the past few years, the subject of many debates has been the identification of optimal BMS or DES strategies for improving angiographic success, reducing the risk of peri-procedural complications, and decreasing the rate of restenosis and reintervention. The vast majority of registry studies (BMS and DES) and randomized studies (DES) have demonstrated that the systematic stenting of both branches is not superior to the strategy of ‘provisional side-branch stenting’. Indications for systematic double stenting as well as the type of strategy to be implemented are still being debated because of heterogeneous studies with respect to lesion type, and of the multiplicity of inadequately described or applied techniques.
Adapting the technique to the lesion, as reported by several recent randomized studies, is complicated by the emergence of a new prognostic factor, namely the angle or angles of the bifurcation, which are still very difficult to measure precisely.
Various types of ‘dedicated’ stents specifically designed for bifurcation lesions have been included in debates about the adaptation of the technique (or stent) to the type of bifurcation lesion to be treated.
Finally, stenting of bifurcation lesions has been shown to be a risk factor of acute, late, or very late stent thrombosis and the influence of the technique or its imperfect implementation, has not been adequately assessed.
The purpose of the present chapter is to provide an overview of coronary bifurcation lesions and their current treatment and address the fundamental as well as practical issues inherent in this setting.
Chapter. 13026 words. Illustrated.
Subjects: Radiology ; Cardiovascular Medicine
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