A prospective, randomized, multicenter study in patients with an indication for coronary artery revascularisation who have been accepted for percutaneous coronary intervention (PCI) of the left main coronary artery. Patients will undergo standard PCI of the left main coronary artery and will be randomized in a 1:1 fashion to the Synergy stent or to the XIENCE stent. Dual antiplatelet therapy (DAPT) will be stopped at t=4 months in the Synergy arm whereas in the control arm DAPT will be continued for 12 months. A subgroup of 100 patients will have control angiography with Optical Coherence Tomography (OCT) at t=3 months after treatment.

PCI of the left main coronary artery is a complex procedure with increased risk of both short and long-term major cardiac adverse events. With the use of coronary artery stents the outcome has significant improved and PCI of the left main is included in the European Society Cardiology guidelines [8]. However the results of first generation drug eluting stents still show significant room for improvement, as the risk of very late stent thrombosis has been shown to accrue up to 5 year follow-up. The newest generation of drug eluting stents have improved radial strength with thinner strut thickness, bioresorbable coatings for local drug delivery which are resorbed in 3 months and are applied only direct to the vessel wall. These stents have been evaluated in non-complex disease with good results. A comparison of the newest generation drug eluting stents in combination with a short duration of dual antiplatelet therapy versus current standard PCI techniques in complex PCI of left main coronary artery disease is therefore desirable.

The study stent (Synergy) is an evolution of currently used drug eluting stents and in initial trials demonstrated similar results for surrogate endpoints [4,5] On clinical endpoints no difference has been demonstrated. This results in a very small possibility of inferiority to current stents where re-intervention is the largest risk. For shortening DAPT several non-randomized studies have shown high safety with a very low risk (1%) of stent thrombosis [6]. Based on the improved properties of the study stent (biodegradable coating) the risk of early DAPT discontinuation should be minimal. For the relevant subgroup control coronary angiography with the additional use of OCT imaging can be considered a standard procedure with a very low risk of major complications (0.4%) [7] This study will investigate the short term angiographic and long term clinical outcome of after implantation of an improved drug eluting coronary artery stent (Everolimus-eluting Platinum Chromium Stent with Abluminal Bioabsorbable Polymer) with shorter post interventional dual antiplatelet therapy (DAPT) in comparison to a conventional drug eluting stent with a permanent Polymer followed by 12 months DAPT for treatment of unprotected left main coronary artery disease.

Inclusion Criteria:

• Patients with an indication for coronary artery revascularisation by ESC guidelines and accepted for PCI of the left main coronary artery will be included in the study.

Main inclusion criteria:

1. Patient has an indication for coronary artery revascularisation of the left main artery in accordance with the ESC guidelines
2. Patient has been discussed with the cardiac surgeon prior to PCI procedure
3. Patient is accepted for PCI
4. Patient is at least 18 years of age.
5. The patient understands and accepts the meaning and the aims of the study and is willing to provide written informed consent
6. The patient is willing to comply with specified follow-up evaluation and can be contacted by telephone.

Exclusion Criteria:

1. Not able to receive anti-platelet treatment due to contraindications
2. Known allergy to acetylsalicylic acid, clopidogrel, prasugrel or ticagrelor
3. Cardiogenic shock
4. STEMI within the last 5 days
5. Planned surgery within 12 months after stent introduction
6. History of bleeding diathesis or active major bleedings
7. Major surgery within previous 15 days
8. Current participation in another trial which has not yet reached its primary endpoint
9. Life expectancy < 12 months
10. Hypersensitivity or contraindication to everolimus or structurally-related compounds, cobalt, chromium, nickel, tungsten, acrylic, platinum and fluoropolymers
11. Female patient with child bearing potential not taking adequate contraceptives or currently breastfeeding