The Stent or Surgery (SoS) Trial

A Randomised Controlled Trial to Compare Coronary Artery Bypass Grafting With Percutaneous Transluminal Coronary Angioplasty and Primary Stent Implantation in Patients With Multi-Vessel Coronary Artery Disease

This study compared two different methods of restoring blood flow to the heart when there has been a narrowing or blockage in the blood vessels that supply the heart. Currently there are two different ways of restoring blood flow. One is heart surgery where a surgeon operates directly on the heart, through an incision in the breast bone (sternum) and takes segments of the patient's (non-essential) veins or arteries and then uses these to bypass blocked or narrowed segments in the coronary arteries. This way additional blood can be "piped" into the heart muscle wall. The second method is coronary angioplasty with stent implantation. Coronary angioplasty is a non-surgical method performed under a local anaesthetic. During angioplasty a special balloon is advanced to the site of a coronary narrowing, then inflated to make it expand and this action removes the narrowing. This is a more simple and less invasive than surgery but its value has been limited by a tendency for narrowings to reoccur(restenosis) in the six months following the treatment. When this happens a repeat procedure is often performed. To reduce the incidence of restenosis coronary stents are implanted. These are tubular metal scaffold devices that are placed inside a coronary artery at the site of a previous narrowing to help keep the artery open. These devices are usually delivered on an angioplasty balloon and expanded into place. Both treatments are equally effective at preventing death and subsequent myocardial infarction and most doctors are happy to recommend either option. Angioplasty offers a more simple initial procedure but with a chance of needing a repeat performance. Bypass surgery represents a more significant initial undertaking with a longer recovery and convalescent period but in most cases, provides good relief of symptoms. Patient preference plays an important part in the decision process. Bypass grafting is currently the therapy most frequently performed world-wide. Angioplasty has a number of important advantages but the need for repeat procedures currently limits its appeal. Since these trials were performed there have been important advances in angioplasty techniques. Prominent amongst these has been the development and use of Coronary Stents which has been shown (in clinical trials) to reduce the need for repeat procedures after an initial angioplasty. Consequently stent implantation is now in routine use world wide. If angioplasty is performed with coronary stent implantation then this may reduce the need for repeat procedures and address the principal factor currently limiting the value of this approach. If the results were found to be as good as with bypass grafting then patients could benefit from a shorter hospital stay, a less traumatic operation and a shorter recovery period. We therefore wish to compare the outcomes in patients treated with a) bypass grafting or b) angioplasty with coronary stent implantation.

Inclusion Criteria: Written informed consent. Patient has typical angina pectoris - stable or unstable symptoms. Atherosclerotic coronary artery disease demonstrated with selective coronary angiography with a significant lesion present in at least two of the principal epicardial vessel systems. Revascularisation procedure clinically indicated. Nominated trial surgeon accepts the patient for CABG. Nominated trial interventionist accepts the patient for PTCA and stent. At least one identified lesion suitable and targeted for primary stent implantation. A procedure for the completion of either revascularisation strategy can be performed within 6 weeks of randomisation. Exclusion Criteria: Previous CABG procedure or other thoracotomy. Previous coronary interventional procedure (of any type). Intervention on any cardiac valve scheduled for the index revascularisation procedure. Excision or other intervention on the myocardium scheduled for the index revascularisation procedure. Intervention on the great vessels, carotid arteries or aorta scheduled for the index revascularisation procedure. Absent autologous graft material. Non-cardiac disease influencing survival. Acute myocardial infarction in the 48 hours preceding the proposed revascularisation procedure. Participation in any other study that would involve deviation from the routine local management of a revascularisation procedure. Allergy to anti-platelet agents in local use. Language or other communication barrier. Follow-up for two years not possible / Patient unreliable.

Booth J, Clayton T, Pepper J, Nugara F, Flather M, Sigwart U, Stables RH; SoS Investigators. 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 Jul 22;118(4):381-8. doi: 10.1161/CIRCULATIONAHA.107.739144. Epub 2008 Jul 7.