Elsevier

The Lancet

Volume 391, Issue 10124, 10–16 March 2018, Pages 939-948
The Lancet

Articles
Mortality after coronary artery bypass grafting versus percutaneous coronary intervention with stenting for coronary artery disease: a pooled analysis of individual patient data

https://doi.org/10.1016/S0140-6736(18)30423-9Get rights and content

Summary

Background

Numerous randomised trials have compared coronary artery bypass grafting (CABG) with percutaneous coronary intervention (PCI) for patients with coronary artery disease. However, no studies have been powered to detect a difference in mortality between the revascularisation strategies.

Methods

We did a systematic review up to July 19, 2017, to identify randomised clinical trials comparing CABG with PCI using stents. Eligible studies included patients with multivessel or left main coronary artery disease who did not present with acute myocardial infarction, did PCI with stents (bare-metal or drug-eluting), and had more than 1 year of follow-up for all-cause mortality. In a collaborative, pooled analysis of individual patient data from the identified trials, we estimated all-cause mortality up to 5 years using Kaplan-Meier analyses and compared PCI with CABG using a random-effects Cox proportional-hazards model stratified by trial. Consistency of treatment effect was explored in subgroup analyses, with subgroups defined according to baseline clinical and anatomical characteristics.

Findings

We included 11 randomised trials involving 11 518 patients selected by heart teams who were assigned to PCI (n=5753) or to CABG (n=5765). 976 patients died over a mean follow-up of 3·8 years (SD 1·4). Mean Synergy between PCI with Taxus and Cardiac Surgery (SYNTAX) score was 26·0 (SD 9·5), with 1798 (22·1%) of 8138 patients having a SYNTAX score of 33 or higher. 5 year all-cause mortality was 11·2% after PCI and 9·2% after CABG (hazard ratio [HR] 1·20, 95% CI 1·06–1·37; p=0·0038). 5 year all-cause mortality was significantly different between the interventions in patients with multivessel disease (11·5% after PCI vs 8·9% after CABG; HR 1·28, 95% CI 1·09–1·49; p=0·0019), including in those with diabetes (15·5% vs 10·0%; 1·48, 1·19–1·84; p=0·0004), but not in those without diabetes (8·7% vs 8·0%; 1·08, 0·86–1·36; p=0·49). SYNTAX score had a significant effect on the difference between the interventions in multivessel disease. 5 year all-cause mortality was similar between the interventions in patients with left main disease (10·7% after PCI vs 10·5% after CABG; 1·07, 0·87–1·33; p=0·52), regardless of diabetes status and SYNTAX score.

Interpretation

CABG had a mortality benefit over PCI in patients with multivessel disease, particularly those with diabetes and higher coronary complexity. No benefit for CABG over PCI was seen in patients with left main disease. Longer follow-up is needed to better define mortality differences between the revascularisation strategies.

Funding

None.

Introduction

Numerous randomised trials1, 2, 3 have compared coronary artery bypass grafting (CABG) with percutaneous coronary intervention (PCI) with balloon angioplasty, bare-metal stents, or drug-eluting stents for the treatment of multivessel or left main coronary artery disease. In 2009, Hlatky and colleagues1 reported the results of a pooled analysis of individual patient data from ten randomised trials involving 7812 patients assigned to CABG or PCI with balloon angioplasty or bare-metal stents. In that study, 5 year mortality was 8·4% after CABG and 10·0% after PCI (p=0·12). More recent trials4, 5, 6, 7, 8, 9, 10 comparing CABG with PCI with drug-eluting stents have found similar mortality for the revascularisation strategies. However, to date, no clinical trial has been sufficiently powered to detect a difference in all-cause mortality between CABG and PCI using stents.

To overcome this limitation, we did a pooled analysis of individual-patient data from randomised trials comparing CABG with PCI using stents to examine the comparative effects of these interventions on long-term all-cause mortality in all patients with coronary artery disease and separately in patients with multivessel or left main disease.

Research in context

Evidence before this study

We searched MEDLINE, Embase, and the Cochrane Library up to July 19, 2017, to identify randomised clinical trials comparing coronary artery bypass grafting (CABG) with percutaneous coronary intervention (PCI) using stents. We used the search terms “coronary artery bypass grafting”, “percutaneous coronary intervention”, “stent”, and “random*”. Studies were included if the patients had multivessel or left main coronary artery disease and did not present with acute myocardial infarction, PCI was done with bare-metal or drug-eluting stents and not balloon angioplasty, and more than 1 years' follow-up for all-cause mortality was available. We identified 12 high-quality trials. One trial found a survival benefit of CABG over PCI with bare-metal stents for multivessel disease at 6 years' follow-up. Another trial found better survival at 5 years' follow-up with CABG than with PCI using first-generation drug-eluting stents in patients with multivessel disease and diabetes. However, these results have not been reproduced in other individual trials with 3–10 years' follow-up, except in underpowered and hypothesis-generating subgroup analyses. Two pooled analyses of CABG versus PCI with balloon angioplasty or bare-metal stents for multivessel disease found conflicting results, and what the survival differences are between CABG and PCI remains largely unclear.

Added value of this study

This study is the largest analysis of patients randomly assigned to PCI using stents or to CABG. To our knowledge, this study shows for the first time that all-cause mortality is significantly lower with CABG than with PCI in an overall randomised population of patients with multivessel or left main coronary artery disease. Additionally, the use of individual patient data allowed identification of important subgroups that have a survival benefit from CABG. These subgroups include patients with multivessel disease and diabetes and those with higher coronary lesion complexity (established with the Synergy between PCI with Taxus and Cardiac Surgery [SYNTAX] score). Patients with left main disease had similar survival with PCI and CABG, regardless of diabetes and SYNTAX score.

Implications of all the available evidence

Some patients have specific indications for PCI or CABG, such as coronary complexity too high for PCI or operative risk too high for CABG. In patients with estimated clinical equipoise, as determined by heart teams, consideration of disease type (multivessel or left main), coronary complexity, and diabetes status is crucial because these are important treatment effect modifiers of favourable mortality after CABG versus PCI and should affect decisions on coronary revascularisation in daily practice. However, longer follow-up of randomised trials is needed to better define mortality differences in overall patients and specific subgroups.

Section snippets

Study selection and data collection

We searched MEDLINE, Embase, and the Cochrane Library up to July 19, 2017, using the search terms “coronary artery bypass grafting”, “percutaneous coronary intervention”, “stent”, and “random*”. Two researchers (SJH and MM) independently identified randomised trials comparing CABG with PCI in which patients had multivessel or left main coronary artery disease and did not present with acute myocardial infarction, PCI was done with stents (bare-metal or drug-eluting) and not balloon angioplasty,

Results

We identified 19 relevant trials in the literature search, of which seven were excluded because patients did not have multivessel or left main disease (n=4), only 54% of PCI procedures were done with a stent (n=1), or follow-up was only available up to 1 year (n=2; appendix). The principal investigators of the remaining 12 trials4, 5, 6, 7, 8, 9, 10, 14, 15, 16, 17, 18 were contacted to obtain individual patient data for a pooled analysis; one trial14 involving 105 patients was unable to

Discussion

This collaborative analysis of individual patient data from 11 randomised trials is the first large-scale study to compare CABG with PCI with stents. We found that 5 year all-cause mortality was higher after PCI than after CABG in 11 518 patients. In subgroup analyses, CABG only had a mortality benefit over PCI in patients with multivessel disease and diabetes; no difference was seen in patients with multivessel disease without diabetes, nor in patients with left main disease (with or without

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