Comparative Effectiveness of CABG and PCI ORIGINAL RESEARCH CABG over 5 years is an underestimate of the lifetime Peripheral arterial disease may serve as a marker for pa effect of treatment because the CABG and PCI survival tients with more extensive coronary atherosclerosis, for curves are separated for up to 10 years(Figure 1)and whom CABG may provide a greater survival advantage, ubsequent follow-up is limited. Although a lifetime esti- but data on coronary anatomy were not available in this mate of the life-years added by CABG would be preferable, study to evaluate this possibility it would require many additional extrapolations Neverthe Compared with PCI, CABG was associated with lower effectiveness of CABG and PCI further amplify the d e mortality among patents with a history of tobacco use, but less, our finding that the variations in the comparativ the reasons for this association are uncertain previous ferences in expected survival among patient subgroups studies have shown that patients who quit smoking after (Figure 4)is an important insight for clinical decisio coronary revascularization have better outcomes than those who continue to smoke(12, 13)and that DaTes(14) Because patients with diabetes have a higher risk and a likely to quit smoking after CABG than after PCI (14) disproportionate treatment effect from CABG relative to More patients in this study may have quit smoking after PCI(Figure 2), they have a particularly large difference in CABG than after PCI, adding to any survival advantage survival if treated with CABG rather than PCI (Figure 4) from the procedure itself. Data available in this study did The strong effect of CABG on survival compared with PCI not distinguish between current and former smokers, and among patients with diabetes and multivessel coronary dis- we could not identify patients who continued to smoke ease was recently confirmed by a large randomized trial of after revascularization. Further study of the complex rela 1900 patients(11) tionships among smoking, coronary revascularization, and Coronary artery bypass grafting was also associated outcomes is warranted with a particularly lower mortality than PCI among pa- Coronary artery bypass grafting was also associated tients with a history of peripheral arterial disease(Figures 2 with lower mortality than PCI among patients with a his- and 4). A similar trend was present in the pooled data from tory of heart failure(interaction P<0.001). Such patients 10 randomized trials, but only 665 patients in that study have not been well-represented in clinical trials. Only 3% had peripheral arterial disease and the interaction test was of patients in the 10 randomized trials had a history of not significant(interaction P= 0.33). Our study includes heart failure, compared with 13% in our analysis of Medi- more than 18 000 patients with a diagnosis of peripheral care beneficiaries. Consequently, the comparative effective- arterial disease, so it had sufficient statistical power to de- ness of CABG and PCI in patients with heart failure tect a difference in the treatment effect in this subgroup. has not been well-studied. The claims data we used for Figure 4. Distribution of the estimated life-years of survival added by CABG compared with PCI over 5 y in clinical subgroups No Yes Diabetes Heart Failure Peripheral Arterial Disease nd-whisker plots indicate the 50ch percentile as the line within the box; the 25th and 75th percentiles as the bottom and of the box ely: and the Sth and 95th- ses a Prcutaneous coronary intervention the bottom and top whiskers, respectively. The mean is indicated by the poi the box CABG coronary artery by 21 May 2013 Annals of Internal Volume158· Number107CABG over 5 years is an underestimate of the lifetime effect of treatment because the CABG and PCI survival curves are separated for up to 10 years (Figure 1) and subsequent follow-up is limited. Although a lifetime esti￾mate of the life-years added by CABG would be preferable, it would require many additional extrapolations. Neverthe￾less, our finding that the variations in the comparative effectiveness of CABG and PCI further amplify the dif￾ferences in expected survival among patient subgroups (Figure 4) is an important insight for clinical decision making. Because patients with diabetes have a higher risk and a disproportionate treatment effect from CABG relative to PCI (Figure 2), they have a particularly large difference in survival if treated with CABG rather than PCI (Figure 4). The strong effect of CABG on survival compared with PCI among patients with diabetes and multivessel coronary dis￾ease was recently confirmed by a large randomized trial of 1900 patients (11). Coronary artery bypass grafting was also associated with a particularly lower mortality than PCI among pa￾tients with a history of peripheral arterial disease (Figures 2 and 4). A similar trend was present in the pooled data from 10 randomized trials, but only 665 patients in that study had peripheral arterial disease and the interaction test was not significant (interaction P 0.33). Our study includes more than 18 000 patients with a diagnosis of peripheral arterial disease, so it had sufficient statistical power to de￾tect a difference in the treatment effect in this subgroup. Peripheral arterial disease may serve as a marker for pa￾tients with more extensive coronary atherosclerosis, for whom CABG may provide a greater survival advantage, but data on coronary anatomy were not available in this study to evaluate this possibility. Compared with PCI, CABG was associated with lower mortality among patients with a history of tobacco use, but the reasons for this association are uncertain. Previous studies have shown that patients who quit smoking after coronary revascularization have better outcomes than those who continue to smoke (12, 13) and that patients are more likely to quit smoking after CABG than after PCI (14). More patients in this study may have quit smoking after CABG than after PCI, adding to any survival advantage from the procedure itself. Data available in this study did not distinguish between current and former smokers, and we could not identify patients who continued to smoke after revascularization. Further study of the complex rela￾tionships among smoking, coronary revascularization, and outcomes is warranted. Coronary artery bypass grafting was also associated with lower mortality than PCI among patients with a his￾tory of heart failure (interaction P
0.001). Such patients have not been well-represented in clinical trials. Only 3% of patients in the 10 randomized trials had a history of heart failure, compared with 13% in our analysis of Medi￾care beneficiaries. Consequently, the comparative effective￾ness of CABG and PCI in patients with heart failure has not been well-studied. The claims data we used for Figure 4. Distribution of the estimated life-years of survival added by CABG compared with PCI over 5 y in clinical subgroups. Predicted Difference (CABG – PCI) in 5-y Survival, y Favors PCI Favors CABG No Yes Tobacco Use No Yes Diabetes No Yes Heart Failure No Yes Peripheral Arterial Disease –0.1 0.0 0.1 0.2 0.3 0.4 0.5 The box-and-whisker plots indicate the 50th percentile as the line within the box; the 25th and 75th percentiles as the bottom and top edges of the box, respectively; and the 5th and 95th percentiles as the bottom and top whiskers, respectively. The mean is indicated by the point within the box. CABG coronary artery bypass graft; PCI percutaneous coronary intervention. Comparative Effectiveness of CABG and PCI Original Research www.annals.org 21 May 2013 Annals of Internal Medicine Volume 158 • Number 10 733