Coronary Artery Bypass Grafting vs Percutaneous Coronary Intervention and Long-Term Mortality and Morbidity in Multivessel Disease: Meta-Analysis of Randomized Clinical Trials of the Arterial Grafting and Stenting Era
What are the comparative effects of coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI) on long-term mortality and morbidity in patients with multivessel disease?
A systematic literature search was conducted for all randomized clinical trials directly comparing CABG with PCI. To reflect current practice, the authors included randomized trials with one or more arterial grafts used in at least 90%, and one or more stents used in at least 70% of the cases that reported outcomes in patients with multivessel disease. Numbers of events at the longest possible follow-up and sample sizes were extracted. To obtain meta-analytic risk ratios (RRs) and 95% confidence intervals (CIs), fixed-effects models using number of events and total sample size were used, unless there was heterogeneity among the included trials. In cases of heterogeneity (defined as I2 > 40%), random-effects models were used.
A total of six randomized trials enrolling 6,055 patients were included, with a weighted average follow-up of 4.1 years. There was a significant reduction in total mortality with CABG compared with PCI (I2 = 0%; RR, 0.73; 95% CI, 0.62-0.86; p < 0.001). There were also significant reductions in myocardial infarction (MI) (I2 = 8.02%; RR, 0.58; 95% CI, 0.48-0.72; p < 0.001) and repeat revascularization (I2 = 75.6%; RR, 0.29; 95% CI, 0.21-0.41; p < 0.001) with CABG. There was a trend toward excess strokes with CABG (I2 = 24.9%; RR, 1.36; 95% CI, 0.99-1.86), but this was not statistically significant (p = 0.06). For reduction in total mortality, there was no heterogeneity between trials that were limited to and not limited to patients with diabetes or whether stents were drug eluting or not. Owing to lack of individual patient-level data, additional subgroup analyses could not be performed.
The authors concluded that in patients with multivessel coronary disease, compared with PCI, CABG leads to an unequivocal reduction in long-term mortality and MIs and to reductions in repeat revascularizations, regardless of whether patients are diabetic or not.
This meta-analysis of the contemporary era shows that in patients with multivessel coronary artery disease, CABG reduces long-term mortality by 27% compared with PCI, regardless of whether the study population is limited to patients with diabetes or not. Regarding major morbidity, a 42% risk reduction in MI was observed in patients randomized to CABG. There was a trend for excess strokes with CABG, probably related to an increase in periprocedural strokes. However, the absolute risk increase in stroke was small compared with the absolute risk reduction in mortality and MI. Given these results and other available data, CABG should be strongly considered as the revascularization method for most patients with multivessel coronary artery disease. At the same time, we must make sure that each patient with coronary artery disease is on optimal guideline-based medical therapy and medical therapy only may be a viable option for many patients with coronary artery disease.
Keywords: Coronary Artery Disease, Myocardial Infarction, Stroke, Coronary Artery Bypass, Diabetes Mellitus, Stents, Percutaneous Coronary Intervention
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