Unprotected left main coronary artery (ULMCA) stenosis has relatively high 
prevalence and exposes patients to a high risk for adverse cardiovascular 
events. The optimal revascularisation strategy (coronary artery bypass surgery 
[CABG] or percutaneous coronary intervention [PCI]) for patients with complex 
coronary artery disease is a topic of continuing debate. The introduction of the 
newer-generation drug-eluting stents (DES) -with documented improvements in both 
safety and efficacy- has prompted the interventional community to design two new 
dedicated randomised trials comparing CABG and PCI: the NOBLE (Coronary Artery 
Bypass Grafting Vs Drug Eluting Stent Percutaneous Coronary Angioplasty in the 
Treatment of Unprotected Left Main Stenosis) and EXCEL (Evaluation of XIENCE 
Everolimus Eluting Stent Versus Coronary Artery Bypass Surgery for Effectiveness 
of Left Main Revascularization) trials. The aims of the present review are to 
describe the similarities and contrasts between these two trials as well to 
explore their future implications in ULMCA treatment.