Myocardial infarction (MI) results from a blockage in one or more of the coronary arteries and represents the largest single cause of death worldwide [1]. Even before the introduction of coronary-artery bypass grafting (CABG) in 1968, the focus of treatment and research was opening the blocked artery. Percutaneous coronary intervention (PCI) was first used in 1977, and includes angioplasty, bare-metal stents and more recently, drug-eluting stents (DES). Heart surgeons and cardiologists have argued for the last 30 years over the best way to open up coronary arteries. There have been many attempts to compare the two techniques in randomized controlled trials but there have been several obstacles. Rapid advances have made comparisons difficult. CABG has evolved into off-pump surgery with smaller incisions using arterial conduits, whilst PCI has advanced at least as rapidly with improvements in stent technology, drug therapy and imaging. Other obstacles have included selection of comparable patients, inadequate long-term follow-up and heterogeneous outcome measures. Even when survival rates are the same, stenting leads to more re-do procedures than CABG, causing significantly higher rates of MI and stroke at 5 years [2]. Trials have highlighted long-term survival advantages of CABG versus PCI, particularly in the setting of multi-vessel disease [3] and particularly for diabetic patients. DES have reduced rates of re-do procedures compared with earlier stents. Consequently, their use has rocketed globally, even in multi-vessel disease, where the evidence base is lacking. The Syntax trial aimed to fill this evidence gap and last week, the NEJM published the results [4]. 1800 patients with untreated left mainstem or triple-vessel disease were randomised to either CABG or DES in North American or European centres. At 1 year, rates of MI and stroke were 12.4% in the CABG group and 17.8% in the PCI group. 13.5% of the PCI group and 5.9% of the CABG group needed re-do procedures by 1 year. There is now unequivocal evidence that in the setting of multi-vessel disease, CABG outperforms PCI and should be the gold standard. Randomised trials are the best way to fully evaluate new therapies, and if therapies are rolled out without the evidence, then as with DES, this may turn out to be contrary to best clinical practice. The difference in outcomes after greater than 5 years follow-up and the relative benefits of CABG versus PCI in patients above the age of 80 [5] are examples of gaps in our knowledge which have to be addressed in the same way by future trials.

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1. Mortality by cause for eight regions of the world: Global Burden of Disease Study Lancet 1997; 349:1269-76. Murray CJ, Lopez AD.
2. Long-term safety and efficacy of percutaneous coronary intervention with stenting and coronary artery bypass surgery for multivessel coronary artery disease: a meta-analysis with 5-year patient-level data from the ARTS, ERACI-II, MASS-II, and SoS trials Circulation 2008; 118: 1146-1154.  Daemen J, Boersma E, Flather M, et al.
3. Randomized, controlled trial of coronary artery bypass surgery versus percutaneous coronary intervention in patients with multivessel coronary artery disease: six-year follow-up from the Stent or Surgery Trial (SoS) Circulation 2008;118: 381-388.  Booth J, Clayton T, Pepper J, et al.
4. Percutaneous coronary intervention versus coronary-artery bypass grafting for severe coronary artery disease N Engl J Med. 2009; 360 (10):961-72. Serruys PW, Morice MC, Kappetein AP, Colombo A, Holmes DR, Mack MJ, Ståhle E, Feldman TE, van den Brand M, Bass EJ, Van Dyck N, Leadley K, Dawkins KD, Mohr FW; SYNTAX Investigators.
5. Comparison of coronary revascularization procedures in octogenarians: a systematic review and meta-analysis Nat Clin Pract Cardiovasc Med. 2008; 5(11):738-46. Review. McKellar SH, Brown ML, Frye RL, Schaff HV, Sundt TM 3rd.