Incomplete and Inappropriate Coronary Bifurcation Classification

Re: Provisional vs. Complex Stenting Strategy for Coronary Bifurcation Lesions: Meta-Analysis of Randomized Trials

The use of incomplete and inappropriate Medina coronary bifurcation classification has led to major flaws in randomized clinical trials of coronary bifurcation interventions Dear Editor: With great interest we read the recently published manuscript entitled: “Provisional vs. complex stenting strategy for coronary bifurcation lesions: meta-analysis of randomized trials.”1 In this meta-analysis, the authors concluded that provisional stenting is associated with a lower myocardial infarction rate in comparison to more complex stenting techniques. However, the authors did not realize that all of the randomized clinical studies in their meta-analysis did not separate so called ”true bifurcation lesions” from other less relevant lesions and failed to include bifurcation angle in their analysis. The main reason for this disparity among the studies is the exclusive use of the Medina bifurcation classification which lacks a description of the bifurcation angle and also does not have a distinct description of true bifurcation lesions (meaning that both main and side branch ostia have significant disease). True bifurcation lesions are separated into 3 clinically irrelevant groups (1.1.1, 1.0.1 and 0.1.1) in the Medina classification. This is in contrast to the Movahed bifurcation classification2-4 which summarizes all true bifurcation lesions into one clinically relevant category, so-called B2 lesions. For example, the label of “B2V” would indicate bifurcation lesions (B), with both main and sidebranch ostia involved2 with a description of the severity of the bifurcation angle (in this case a V, indicating a shallow less than 70 degree angle versus a T, which corresponds to a steep angle).3,5 Including low risk bifurcation lesions such as 1m (only main branch has disease) or 1s (only side branch has disease) in randomized bifurcation trials is obsolete. The risk of a side or main branch occlusion in 1m or 1s lesions using single stent technique is very low. Therefore, in clinical practice no one would consider a complex technique using two stents in these lesions. Furthermore, the bifurcation angle is a very important factor for outcome and technical success6-8 which are completely ignored in the randomized bifurcation trials due to exclusive use of the Medina classification causing major flaws in these trials. None of the trials in this meta-analysis have outcome data for true bifurcation lesions or lesions with different angulations. For a legitimate comparison, randomized bifurcation trials should have only included B2 lesions in their studies, as B2 lesions are the only relevant lesions at high risk for side branch occlusion using one stent technique. Subgroup analysis based on lesion angulation should have been performed to adequately assess outcomes. In order to perform meaningful coronary bifurcation studies, we recommend that the most appropriate and complete Movahed coronary bifurcation classification to be used which includes bifurcation angles. Figure 1 summarizes major coronary bifurcation classifications. Figure 2 shows originally published details of the Movahed bifurcation classification. Mohammad Reza Movahed, MD, PhD, FSCAI, FACC, FACP Associate Professor of Medicine Medical Director of Heart Transplant Program The Southern Arizona VA Health Care System The University of Arizona Sarver Heart Center Department of Medicine, Division of Cardiology 1501 North Campbell Ave. Tucson, AZ 85724 Tel: (520)-626-2000 E-mail: rmovahed@email.arizona.edu The author reports no financial conflicts of interest regarding the content herein.

References

1. Hakeem A, Khan FM, Bhatti S, et al. Provisional vs. complex stenting strategy for coronary bifurcation lesions: Meta-analysis of randomized trials. J Invasive Cardiol 2009;21:589–595. 2. Movahed MR. Letter by Movahed regarding article, "Randomized Study of the Crush Technique Versus Provisional Side-Branch Stenting in True Coronary Bifurcations: The CACTUS (Coronary Bifurcations: Application of the Crushing Technique Using Sirolimus-Eluting Stents) Study." Circulation 2009;120:e63; author reply e64. 3. Movahed MR, Stinis CT. A new proposed simplified classification of coronary artery bifurcation lesions and bifurcation interventional techniques. J Invasive Cardiol 2006;18:199–204. 4. Movahed MR. Quantitative angiographic methods for bifurcation lesions: A consensus statement from the European Bifurcation Group. Shortcoming of the Medina classification as a preferred classification for coronary artery bifurcation lesions in comparison to the Movahed classification. Catheter Cardiovasc Interv 2009;74:817–818. 5. Movahed MR. Coronary artery bifurcation lesion classifications, interventional techniques and clinical outcome. Expert Rev Cardiovasc Ther 2008;6(2):261–274. 6. Dzavik V, Kharbanda R, Ivanov J, et al. Predictors of long-term outcome after crush stenting of coronary bifurcation lesions: Importance of the bifurcation angle. Am Heart J 2006;152:762–769. 7. Ormiston JA, Currie E, Webster MW, et al. Drug-eluting stents for coronary bifurcations: Insights into the crush technique. Catheter Cardiovasc Interv 2004;63:332–336. 8. Tan K, Sulke N, Taub N, Sowton E. Clinical and lesion morphologic determinants of coronary angioplasty success and complications: current experience. J Am Coll Cardiol 1995;25:855–865.