Study	Objective	Endpoints	Design	Follow-up	Patients & Lesion	Method	Results	Conclusion & Limitation
Park 2001 (32)	Effect of debulking & IVUS guidance on elective stenting of unprotected left main coronary artery (LMCA) stenosis Nov 1995 – April 2000	Procedural success: <30% residual diameter stenosis by QCA & no procedural or in hospital complications Angiographic MLD, restenosis rates MACE = cardiac death, non-fatal MI & TLR	Non-randomized observation al study Patients IVUS 77 No IVUS 50 Use of IVUS @ discretion of the operator	Angiographic follow-up @ 6 months Clinical following -up up to 2 years	Patients: Consecutive patients Inclusion criteria -Symptomatic LMCA disease or documented MI -Angiographic evidence of ≥50% diameter stenosis of LMCA Exclusion criteria -Contraindication to antiplatelet or anticoagulation therapy -LVEF<40%	IVUS Group Preintervention (56) and postintervention (77) IVUS IVUS criteria for optimal stenting Complete stent tovessel wall apposition; lumen CSA≥90% of distal reference lumen CSA; full lesion coverage QCA: analyzed by 2 independent angiographers using on-line QCA system. Angiographic stenosis defined as diameter stenosis>50% @follow-up Directional atherectomy performed before stenting in 40 lesions. All pts received aspirin + coumadinor aspirin + ticlopidine At least 48 hours before stenting	IVUS No IVUS N 77 50 MLD prior (mm)       1.2 (0.5) (0.5)     P= .02 MLD after (mm)       4.2 (0.6) 4.0 (0.6)     P = .003 MLD follow-up (mm)       2.7 (1.0) 2.7 (1.0)     P = .976 Angiographic restenosis %     18.6 19.5     P = .556 For entire cohort: MACE free survival 86.9% @ 1year & 2 years. Survival rate 98.1% @ 1 year &97% @ 2 year	Stenting of unprotected LMCA stenosis might be associated with favourable long-term outcome in selected patients. Guidance with IVUS may optimize the immediate results & debulking before stenting seems to be effective in reducing the restenosis rate. Large-scale RCT needed.
Agostoni 2005 (33)	Assess short & midterm clinical impact of IVUS guidance in elective percutaneo ustreatment of unprotected left main coronary artery disease with drug-eluting stents	Major adverse cardiac events defined as cardiac or non-cardiac death, non-fatal MI, & target vessel revascularization	Non-randomized cohort	Clinical Median 433 days(range 178–780 days)	Elective patients with symptomatic coronary artery disease & >50% occlusion of left main coronary artery. IVUS n = 24 No IVUS n = 34	Vessels measured Q baseline & after procedure with quantitative coronary angiography Unprotected left main coronary artery stented with drug-eluting stent (s) under guidance of coronary angiography or additional IVUS at the discretion of the operator. External elastic membrane areas & lumen cross-sectional area measured with computerized planimetry. Criteria for optimal stent placement: Complete stent-to-stent wall apposition, adequate stent expansion (>80% reference cross-sectional area), full lesion coverage.	Incidence of MACE IVUS 8% No IVUS 20% (P = .18) Univariate analysis: Distal left main involvement & reference vessel diameter were the only significant predictors of MACE. Multivariate analysis: Distal left main disease was theonly significant predictor of MACE (Hazard ratio 7.7, 95% CI 1–62.6, P =.05).	IVUS was not associated with additional clinical benefit with respect to angiographic-assisted stent deployment Major Limitation: Small sample Non-randomized No angiographic follow-up