Few data are available about the late patency of side branches in association with the currently used stent types and implantation techniques.

Among the bifurcation type, bifurcation lesion without significant side branch stenosis (<50%) usually did not require side branch stenting, but owing to several putative mechanism including dissection, thrombosis formation, embolization of plaque debris, ostial compromise by displaced stent strut, and snow plow effect, the side branch might be compromised. In this situation, the strategy to achieve optimal results has not been reported. Recently, FFR study showed that most jailed side branch (vessel size >2.0 mm. DS>50%) after main branch stenting did not have functional significance. We compared strategies with or without routine kissing balloon dilatation for less than 50% stenosis after simple DES crossing for bifurcation lesions (bifurcation type 1.1.0, 1.0.0, and 0.1.0 according to Medina classification) with serial change of FFR measurement.

Inclusion Criteria:

• Clinical

  • Patients with angina and documented ischemia or patients with documented silent ischemia
  • Patients who are eligible for intracoronary stenting
  • Age >18 years, <75 ages

• Angiographic

  • De novo lesion located in a major bifurcation point with the MEDINA classification type 1.1.0, 1.0.0, or 0.1.0
  • Main vessel : >= 2.5 mm in vessel size, >= 50% in diameter stenosis and =< 50 mm in lesion length by visual estimation, in which the lesion is covered with =< 2 stents
  • Side branch :>= 2.0 mm in vessel size and < 50% diameter stenosis by visual estimation

Exclusion Criteria:

• History of bleeding diathesis or coagulopathy

• Pregnant

• Known hypersensitivity or contra-indication to contrast agent, heparin, sirolimus, paclitaxel and zotarolimus

• Limited life-expectancy (less than 1 year) due to combined serious disease

• ST-elevation acute myocardial infarction =< 2 weeks

• Characteristics of lesion:

  • Left main disease
  • In-stent restenosis
  • Graft vessels
  • TIMI flow =< grade 2 in the side branch
  • Chronic total occlusion

• Renal dysfunction, creatinine >= 2.0mg/dL

• Contraindication to aspirin, clopidogrel or cilostazol