A study by Duk-Woo Park et al. has shown that in patients with significant left main coronary artery (LMCA) disease, as compared with CABG, PCI showed similar rates of death and serious composite outcomes, but a higher rate of target-vessel revascularization at 10 years. Moreover, they demonstrated that CABG showed lower mortality and serious composite outcome rates compared with PCI with drug-eluting stents after 5 years.
Comparative outcomes of coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) for left main coronary artery (LMCA) disease were previously reported. However, data on very long-term (>10 years) outcomes are limited. Longer-term follow-up was necessary to examine additional differences between PCI and CABG over time in patients with significant LMCA disease. In light of this, the authors of this study compared 10-year outcomes after PCI and CABG for LMCA disease. In this observational study of the MAIN-COMPARE (Ten-Year Outcomes of Stents Versus Coronary-Artery Bypass Grafting for Left Main Coronary Artery Disease) registry, the authors evaluated 2,240 patients with unprotected LMCA disease who underwent PCI (n ¼ 1,102) or underwent CABG (n ¼ 1,138) between January 2000 and June 2006. Adverse outcomes (death; a composite outcome of death, Q-wave myocardial infarction, or stroke; and target-vessel revascularization) were compared with the use of propensity scores and inverse-probability-weighting adjustment. The follow-up was extended to at least 10 years of all patients (median 12.0 years).
“Given the limited indications for BMS in the contemporary era, these findings are less meaningful from a clinical and therapeutic perspective. By contrast, among DEDES-treated patients, PCI was associated with excess risk for both death and Q-wave MI between 5 and 10 years, whereas results in the first 5 years were comparable between treatment arms. In support of a temporal hypothesis, formal interaction tests between treatment (DES vs. CABG) and time were significant for the outcomes of death and Q-wave MI. Although a late signal for excess DES-associated risk in the context of LM PCI is certainly concerning, these findings must be viewed within the certain design and methodological constraints.”- Dr. George Dangas, M.D.
The investigators found that in the overall cohort, there was no significant difference in adjusted risks of death and the composite outcome between the groups up to 10 years. Moreover, the risk of target-vessel revascularization was significantly higher in the PCI group. Additionally, in the cohort comparing drug-eluting stents and concurrent CABG, the 2 study groups did not differ significantly in the risks of death and the composite outcome at 5 years. However, after 5 years, drug-eluting stents were associated with higher risks of death (hazard ratio: 1.35; 95% confidence interval: 1.00 to 1.81) and the composite outcome (hazard ratio 1.46; 95% confidence interval: 1.10 to 1.94) compared with CABG. Therefore, this longest follow-up study of patients with LMCA disease showed no difference in the rates of death and a composite endpoint of death, Q-wave myocardial infarction, or stroke between PCI and CABG at 10 years. However, in the cohort comparing DES and concurrent CABG among patients with more complex clinical and anatomic characteristics, a longterm benefit of CABG over PCI on mortality and hard clinical endpoints was detected after 5 years. Scrutinizing these findings, Dr. George Dangas remarked, “Given the limited indications for BMS in the contemporary era, these findings are less meaningful from a clinical and therapeutic perspective. By contrast, among DEDES-treated patients, PCI was associated with excess risk for both death and Q-wave MI between 5 and 10 years, whereas results in the first 5 years were comparable between treatment arms. In support of a temporal hypothesis, formal interaction tests between treatment (DES vs. CABG) and time were significant for the outcomes of death and Q-wave MI. Although a late signal for excess DES-associated risk in the context of LM PCI is certainly concerning, these findings must be viewed within the certain design and methodological constraints.”
“The findings by Park et al. motivate a longer-term perspective in the calculus for the choice of CABG versus PCI with DES among patients with LM CAD. This concern is relevant as actuarial survival after coronary revascularization using either surgery or percutaneous approaches continues to lengthen. Definitive conclusions require an experimental evidence base and extended follow-up from the EXCEL (Evaluation of XIENCE Everolimus Eluting Stent Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) and FREEDOM trials are eagerly awaited. Pending such data, the report by Park et al. should not have an impact on current practice, but a note of caution is certainly warranted.”- Dr. Usman Baber, M.D.
Commenting on the study and its impact on clinical medicine, Dr. Usman Baber stated, “The findings by Park et al. motivate a longer-term perspective in the calculus for the choice of CABG versus PCI with DES among patients with LM CAD. This concern is relevant as actuarial survival after coronary revascularization using either surgery or percutaneous approaches continues to lengthen. Definitive conclusions require an experimental evidence base, and extended follow-up from the EXCEL (Evaluation of XIENCE Everolimus Eluting Stent Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) and FREEDOM trials is eagerly awaited. Pending such data, the report by Park et al. should not have an impact on current practice, but a note of caution is certainly warranted.” The authors acknowledge that further research is needed to clarify the mechanisms underlying differences in very long-term vascular outcomes after PCI and CABG for LMCA disease.
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