COMMENTARY: Bifurcations: The Problem is the Side Branch

Bifurcation disease continues to be one of the complex coronary lesion subsets that remains a challenge. The percutaneous treatment of bifurcations is common, accounting for up to 20% of interventions, and the frequency has increased in the era of drug-eluting stents (DES).¹ The therapy of bifurcation lesions is controversial, and the innumerable treatment strategies attest to the current dilemma interventionalists face and the lack of a single, preferred approach.^2–6 The stakes are high, as bifurcation stents often subtend large areas of myocardium and suffer from higher risks of acute (stent thrombosis) and chronic (restenosis) complications.⁷ The key to the therapy of bifurcations is the side branch. This is particularly true now that the reintervention rates in the main branch with DES are quite low.¹ There are a number of questions to ask in each bifurcation intervention, and they predominantly revolve around the side branch. How important clinically is the side branch? What is the side branch diameter? How much myocardium does it supply? Will the side branch cause angina if restenosis occurs or if an inadequate initial result is obtained? Is there a high risk that the side branch will close with main vessel stenting, and if it closes, will it be reaccessible? Is the side branch of such size and the lesion of such complexity that giving up access to the side branch should be avoided? Even with today’s tools, side branches close and cannot be reaccessed. Does side branch angulation favor a particular technique? A shallow angle favors V-stenting, while a more abrupt angulation favors T-stenting. How long is the side branch disease? If only confined to the ostium and short in length, the likelihood that a second stent will be necessary is low. Finally, is the side branch dilatable and will lesion modification with cutting balloon or rotational atherectomy be necessary for complete expansion? All these issues will determine side branch strategy and whether a second side branch stent is necessary. When committed to a two-stent strategy (side-branch and main-branch stenting), which technique is best? There are a myriad of approaches which can be divided into V-stenting/simultaneous kissing stents (SKS), culotte, and T-stenting with or without crush.^2–6,8–10 These various techniques have been developed to facilitate ostial side-branch coverage. All have their limitations. Provisional T-stenting is at present the default approach for most lesions; however, it is limited by sacrificing access to the side branch, even if the side-branch wire is left in during main-branch stenting (trapping of side branch wire).² Furthermore, it can be difficult to optimally place the side branch stent without missing the ostium or having excess stent protruding into the main branch. In this issue, Rizik and colleagues report their results with a modified T-stenting approach, one which does not forfeit wire access before side branch stenting and helps to optimize branch ostial positioning.¹¹ They describe a balloon alignment method to optimize ostial coverage. Following predilatation of the side and main branches, the proximal end of the undeployed branch stent is positioned over the main-branch wire.⁶ The main-branch balloon and side-branch stent are then inflated simultaneously. This is a novel modification of the balloon blocking/pullback technique described by Schwartz and Dardas.^12,13 In the 26 patients described, only 15% required further stenting of the ostium at the time of the original procedure, and only 2 patients had angiographic restenosis, both of which were in the side branch ostia and led to target lesion revascularization. Although access to the branch is sacrificed while the main branch is stented, the inability to reaccess the stented branch vessel, once treated, is low. Although only 20/26 patients had a final kissing inflation, this should be performed in all cases. Despite the number of patients being low and the lesions being confined to the LAD/diagonal distribution, Rizik’s technique has many advantages and merits consideration. We all await simple devices that address the bifurcation problem.^14,15 Until these are available, a variety of creative approaches will be utilized and developed to overcome the limited ability of our current tubuluar stent platforms to optimally treat the ostium of the side branch.

References 1. Ioannis I, Ge L, Colombo A. Contemporary stent treatment of coronary bifurcations. J Am Coll Cardiol 2005;46:1146–1155. 2. Brunel P, Lefevre T, Darremont O, et al. Provisional T-stenting and kissing balloon in the treatment of coronary bifurcation lesions: Results of the French multicenter "TULIPE" study. Catheter Cardiovasc Interv 2006;68:67–73. 3. Helqvist S, Jorgensen E. Kelbaek H. et al. Percutaneous treatment of coronary bifurcation lesions: a novel "extended Y" technique with complete lesion stent coverage. Heart 2006;92:981–982. 4. Moussa I, Costa RA, Leon MB, et al. A prospective registry to evaluate sirolimus-eluting stents implanted at coronary bifurcation lesions using the “crush technique”. Am J Cardiol 2006;97:1317–1321. 5. Brett S, Gunn J. Images in cardiology. Shotgun stenting of the left main coronary artery bifurcation. Heart 2006;92:310. 6. Rizik DG, Dowler DA, Villegas BJ. Balloon alignment T-stenting for bifurcation coronary artery disease using the sirolimus-eluting stent. J Invasive Cardiol 2005;17:437–439. 7. Colombo A, Moses JW, Morice MC, et al. Randomized study to evaluate sirolimus-eluting stents implanted at coronary bifurcation lesions. Circulation 2004;109:1244–1249. 8. Chevalier B, Glatt B, Royer T, et al. Placement of coronary stents in bifurcation lesions by the ‘‘culotte’’ technique. Am J Cardiol 1998;82:943–949. 9. Sharma SK, Choudhury A, Lee J, et al. Simultaneous kissing stents (SKS) technique for treating bifurcation lesions in medium-to-large size coronary arteries. Am J Cardiol 2004;94:913–917. 10. Colombo A, Stankovic G, Orlic D, et al. The modified “T” stenting technique with “crushing” for bifurcation lesions: Immediate results and 30-day outcome. Cathet Cardiovasc Interv 2003;60:145–151. 11. Rizik DG, Klassen KJ, Dowler DA, Villegas BJ. Balloon alignment T-stenting for bifurcation coronary artery disease using the sirolimus-eluting stent. J Invasive Cardiol 2006;18:454–460. 12. Schwartz L, Morsi A. The draw-back stent deployment technique: A strategy for the treatment of coronary branch otial lesions. J Invasive Cardiol 2002;14:66–71. 13. Dardas PS, Tsikaderis DD, Mezilis NE, et al. A technique for type 4a coronary bifurcation lesions: Initial results and 6-month clinical evaluation. J Invasive Cardiol 2003;15:180–183. 14. Miyazawa A, Webster MW, Fitzgerald PJ, Ormiston JA. Novel stent system for bifurcation lesions: Examination by intravascular ultrasound. Catheter Cardiovasc Interv 2006;67:900–903. 15. Lefevre T, Ormiston J, Guagliumi G. The Frontier stent registry: Safety and feasibility of a novel dedicated stent for the treatment of bifurcation coronary artery lesions. J Am Coll Cardiol 2005;46:592–598.