Traditionally, patients presenting with left main stem coronary disease would undergo Coronary Artery Bypass Grafting (CABG) surgery. CABG has been a mainstay in treating cardiac lesions for nearly sixty years and has been much refined since its inception. Minimally invasive techniques not requiring a sternotomy and surgery ‘off-pump’ have greatly increased the number of patients considered eligible for CABG (ICVTS, 2009), however there are still obvious limitations and risks, including length of stay in hospital and recovery time. Percutaneous Coronary Intervention (PCI) offers an alternative method of revascularisation and is recognised as a safe and effective alternative to surgery in most cases, except left main stenosis. Not only is PCI quicker, less invasive and has a significantly shorter recovery time, but it also offers the potential for revolutionising the management of left main lesions.

Two important randomised control trials, NOBLE (Lancet, 2016) and EXCEL (NEJM, 2016) compared PCI and CABG for left main lesions. Interestingly, there was some disparity in results between the two studies that has provoked vibrant discussion within the cardiology community. Whilst the NOBLE trial overall judged CABG to be preferable to PCI in treating left main stem disease, the EXCEL study found that PCI with a best-in-class stent had comparable longer-term outcomes to CABG, and even resulted in a reduced rate of associated complications at 30 days post procedure (a secondary end-point). Gregg W. Stone, MD (Chief Investigator of EXCEL) said: “PCI is an acceptable, perhaps even preferred alternative [to CABG],” because there was an “early” and “profound” advantage for PCI in terms of primary endpoint events, specifically a lower risk of MI. In addition, there was also a significant early benefit in terms of other major adverse events” (TCTMD, 2016). On comparing the two trials, David Stone, MD noted that in the smaller NOBLE study there were some structural changes mid-trial, namely the movement of a primary endpoint and the first 10% of the participants being treated with a stent that was not best-in- class (biolimus-eluting) before switching to a newer-generation stent. He felt that EXCEL was, in contrast, an adequately powered and sized study (TCTMD, 2016).

Looking to the future, the results of these trials ought to provide hope for patients. Despite a difference in outcome, a clear conclusion from NOBLE and EXCEL is that both CABG and PCI will continue to be the mainstay of treatment for left main stem disease and the choice between the two should be made on an individual basis, taking into account the patient’s preference and the expertise of the heart team. Guidelines are unlikely to be changed based upon these findings, however it is worth advising patients that whilst CABG does provide a more definitive solution, PCI being a real option provides many benefits such as quicker return to daily activity and treatment for those not fit for surgery. The importance of the heart team collaborating to assist patients in these difficult decisions therefore becomes ever greater. MedShr is the ideal platform to discover and discuss left main PCI cases with a community of interventional cardiologists. Take a look at this case “Severe Left Main and Multivessel Disease” and share your own experiences by creating a case and starting a clinical discussion. Connect with colleagues in the Left Main PCI Case Discussion Group supported by Medtronic. Connect with Dr Rosie Barnett here.

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Treating Left Main Lesions: PCI or CABG?