Stent or Surgery Trial: 6-Year Follow-Up - SoS: 6-Year Follow-Up


The goal of this study was to assess the safety and efficacy of stent-based percutaneous coronary intervention (PCI) compared with coronary artery bypass grafting (CABG) in the management of patients with multivessel coronary artery disease (CAD).


CABG will be more effective than stent-based PCI in the management of multivessel CAD.

Study Design

  • Randomized

Patients Enrolled: 988
Mean Follow Up: 6 years
Mean Patient Age: 61 years
Female: 21%
Mean Ejection Fraction: 57%

Patient Populations:

Symptomatic multivessel CAD that could be managed by either a percutaneous or surgical approach


  • Previous thoracotomy
  • Previous coronary revascularization
  • Need for surgery on the aorta, great vessels, or valves

Primary Endpoints:

Rate of repeat revascularization after the index procedure

Secondary Endpoints:

  • Death or nonfatal myocardial infarction
  • All-cause mortality
  • Symptoms of angina
  • Medication requirement
  • Cost and cost-effectiveness at 1 year
  • Psychological outcomes

Drug/Procedures Used:

Patients with symptomatic multivessel CAD were randomized to bare-metal stent PCI (n = 488) or CABG (n = 500).

Principal Findings:

Stent or Surgery (SoS) trial 2-year results have been reported previously.

Severe angina, defined as Canadian Cardiovascular Society class 3 or 4, was present in 46% of patients, an acute coronary syndrome was present in 24%, and three-vessel disease was present in 42%. Among the PCI group, 94% of attempted lesions were successfully revascularized (mean of 2.7 lesions per patient). In the CABG group, the mean number of bypass grafts was 2.8 per patient (internal mammary artery was used in 81%).

At a median follow-up of 6 years, the incidence of mortality was 10.9% in the PCI group versus 6.8% in the CABG group (hazard ratio [HR] 1.66, p = 0.022). In the PCI group, there were 22 cardiovascular deaths and 25 noncardiovascular deaths. In the CABG group, there were 17 cardiovascular deaths and 11 noncardiovascular deaths. There was no change in mortality according to baseline angina or severity of CAD. Among diabetics, the HR for mortality was 3.53 (95% confidence interval [CI] 1.14-10.95) favoring CABG, and among nondiabetics, HR for mortality was 1.43 (95% CI 0.89-2.29, p for interaction 0.15).


At a median follow-up of 6 years, CABG was superior to bare-metal PCI by conferring a survival advantage. The same result was observed at the 2-year reporting of SoS. This finding is in contrast to the long-term (5-year) results of the ARTS, ERACI II, and MASS II trials, which found no difference in mortality between PCI and CABG. SoS has been criticized for having a relatively low rate of complete revascularization in the PCI arm (54%, compared with 72% in the PCI arm of ARTS). It is unclear if drug-eluting stent PCI would have altered the results.


Booth J, Clayton T, Pepper J, et al. 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 7:[Epub ahead of print].

Keywords: Coronary Artery Disease, Acute Coronary Syndrome, Follow-Up Studies, Drug-Eluting Stents, Mammary Arteries, Confidence Intervals, Coronary Artery Bypass, Diabetes Mellitus, Stents, Percutaneous Coronary Intervention

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