What is the efficacy of coronary artery bypass grafting (CABG)?

Updated: Dec 04, 2019
  • Author: Rohit Shahani, MD, MS, MCh; Chief Editor: Karlheinz Peter, MD, PhD  more...
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In patients with multivessel coronary disease, coronary artery bypass grafting (CABG), as compared with percutaneous coronary intervention (PCI), leads to a reduction in long-term mortality and myocardial infarctions (MIs) as well as reductions in repeat revascularizations, regardless of whether patients are diabetic are not, according to a meta-analysis of six randomized clinical trials comprising 6055 patients from the era of arterial grafting and stenting. [29]

In a meta-analysis of eight randomized studies that included a total of 3612 adult patients with diabetes and multivessel coronary artery disease (CAD), treatment with CABG significantly reduced the risk of all-cause mortality by 33% at 5 years, as compared with PCI. This relative risk reduction did not differ significantly when patients who underwent CABG were compared with subgroups of patients who received either bare metal stents or drug-eluting stents. [30, 31]

In a study of 3723 patients with multivessel coronary disease that compared whether the effect on survival from PCI (n = 1097) compared with CABG (n = 5626) is related to the age of the patient, Benedetto et al found that CABG resulted in a significant reduction in late-phase mortality across all age groups compared to PCI. [32] At a mean follow-up of 5.5 ± 3.2 years, there were 301 deaths overall (PCI: 208; CABG: 93). Overall survival for the PCI group was 95% at 1 year, 84% at 5 years, and 75% at 8 years compared to 95% at 1 year, 92.4% at 5 years, and 90% at 8 years for the CABG group. [32]

In a retrospective (1997-2013), nationwide, population-based Swedish study that evaluated long-term survival, major adverse cardiovascular events, and factors associated with elevated risk in 4086 young adults (≤50 years) undergoing CABG, Dalen et al found better outcomes in younger adults than their older counterparts. [33] At a median follow-up of 10.9 years, 490 (12%) patients died, with 96% survival at 5 years, 90% at 10 years, and 82% at 15 years. The survival of patients aged 51 to 70 years and those older than 70 years who underwent CABG during the same period was significantly worse. The primary risk factors for all-cause mortality were chronic kidney disease, reduced left ventricular ejection fraction, peripheral vascular disease, or chronic obstructive pulmonary disease. [33]

Results of the Surgical Treatment for Ischemic Heart Failure (STICH) Extension Study (STICHES), which evaluated the long-term, 10-year outcomes of CABG in 1212 patients with ischemic cardiomyopathy and an ejection fraction of 35% or less, concluded that the rates of death from any cause, death from cardiovascular causes, and death from any cause or hospitalization for cardiovascular causes were significantly lower in patients who underwent CABG and received medical therapy than among those who received medical therapy alone. [34]

In single-center retrospective analysis (2003-2013) of 763 elderly patients (age ≥75 years) with multivessel disease who underwent PCI or CABG within 30 days of the index catherization, CABG was associated with the best overall clinical outcomes. [35] However, only 20% of the patients (n = 150) underwent CABG. The best treatment strategy for this population remains to be determined. [35]

Similarly, results from analysis of 2007-2014 data from the National Cardiovascular Data Registry Acute Coronary Treatment and Intervention Outcomes Network Registry-Get With The Guidelines that evaluated trends in CABG utilization and in-hospital outcomes showed that CABG was used infrequently in 15,145 patients with ST-segment elevation myocardial infarction (STEMI) during the index hospitalization, with CABG rates declining over time. [36]  In addition, there was a wide hospital-level variation in CABG rates in STEMI, and CABG was generally performed within 1-3 days following angiography. In-hospital mortality rates were similar for patients who underwent CABG and those who did not. [36]

In a meta-analysis of comparison of 5-year outcomes of PCI with drug-eluting stents versus CABG in 6637 patients with unprotected left main CAD from nine studies over a 14-year period (2003-2016), PCI with drug-eluting stents was associated with equivalent cardiac and all-cause mortality but lower rates of stroke and higher rates of repeat revascularization. [37] A trend favoring CABG over PCI for major adverse cardiac and cerebrovascular events did not reach statistical significance.

With regard to quality of life following CABG compared with PCI for multivessel CAD, both interventions provide improvements in the frequency of angina. [38] However, at 1 month postprocedure, PCI patients appear to recover faster and have improved short-term health status compared to patients who undergo CABG, whereas at 6 months and longer postprocedure, CABG patients appear to have greater angina relief and improved quality of life relative to those who undergo PCI. [38]

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