Mortality After CABG vs. PCI for CAD
What are the comparative effects of coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) on long-term all-cause mortality in all patients with coronary artery disease (CAD) and separately in patients with multivessel or left main disease?
The investigators did a systematic review up to July 19, 2017, to identify randomized clinical trials comparing CABG with PCI using stents. Eligible studies included patients with multivessel or left main CAD who did not present with acute myocardial infarction, did PCI with stents (bare-metal or drug-eluting), and had >1 year of follow-up for all-cause mortality. In a collaborative, pooled analysis of individual patient data from the identified trials, the authors 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.
The analysis included 11 randomized trials involving 11,518 patients selected by heart teams who were assigned to PCI (n = 5,753) or to CABG (n = 5,765). A total of 976 patients died over a mean follow-up of 3.8 years (standard deviation [SD] 1.4). Mean SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) score was 26.0 (SD 9.5), with 1,798 (22.1%) of 8,138 patients having a SYNTAX score of 33 or higher. Five-year all-cause mortality was 11.2% after PCI and 9.2% after CABG (hazard ratio [HR], 1.20; 95% confidence interval [CI], 1.06–1.37; p = 0.0038). Five-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. Five-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.
The authors concluded that CABG had a mortality benefit over PCI in patients with multivessel disease, particularly those with diabetes and higher coronary complexity.
This collaborative analysis from 11 randomized trials reports that all-cause mortality is significantly lower with CABG than with PCI in an overall population of patients with multivessel or left main CAD. However, CABG only had a mortality benefit over PCI in patients with multivessel disease and diabetes with no difference in patients with multivessel disease without diabetes, or in patients with left main disease (with or without diabetes). Longer follow-up is essential to better define differences in survival between CABG and PCI because previous landmark analyses have suggested that the risk of mortality was different according to follow-up duration and might show a benefit for CABG over PCI with longer follow-up. Clinicians should consider disease type (multivessel or left main), coronary complexity, and diabetes status, as these are important treatment effect modifiers of favorable mortality after CABG versus PCI and should impact decisions on coronary revascularization.
Keywords: Acute Coronary Syndrome, Cardiac Surgical Procedures, Coronary Artery Bypass, Coronary Artery Disease, Diabetes Mellitus, Mortality, Myocardial Infarction, Percutaneous Coronary Intervention, Stents
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