Lesions of a major coronary artery that involve the origin of or extend into a side branch (bifurcation lesions) have long been recognized as a challenge for catheterbased treatments. Such lesions are present in 2%–16% of stenoses being considered for percutaneous coronary revascularization and are associated with an increased risk of acute complications and late restenosis compared with other lesion morphologies [1]. Consequently, numerous techniques have been proposed for treating such bifurcation stenoses—approaches that include kissing balloon angioplasty, debulking (by directional or rotational atherectomy), and a multitude of stent-based techniques [2].

The simplest approach is to place a stent in only the parent vessel and deal with the side branch as a secondary issue. This is a major shift in perspective from the early stent years, during which the mere presence of a major side branch (whether diseased or not) was itself felt to represent an absolute contraindication to placement of a stent in a coronary segment. Subsequent studies, however, demonstrated that many such side branches remained patent after stenting the parent vessel [3], and even ‘‘jailed’’side branches whose lumen became compromised after stent placement could frequently be treated by adjunctive PTCA through the stent struts [4]. These issues have become commonplace as stents have emerged as the most common form of percutaneous coronary revascularization. Beyond simple balloon dilation rescue of the side branch [4], numerous stent-based techniques have been applied, including rotational ablation of the jailed side branch (for chronic restenosis)[5], kissing stents [6], trousers stents [7], T-stenting [8], and culotte stenting [9]. Among 2,400 coronary interventions performed at Beth