Study Overview
Objective. To compare percutaneous coronary intervention (PCI) using second-generation drug-eluting stents (everolimus-eluting stents) with coronary artery bypass grafting (CABG) among patients with multivessel coronary disease.
Design. Observational registry study with propensity-score matching.
Setting and participants . The study relies on patients identified from the Cardiac Surgery Reporting System (CSRS) and Percutaneous Coronary Intervention Reporting System (PCIRS) registries of the New York State Department of Health. These 2 registries were linked to the New York State Vital Statistics Death registry and to the Statewide Planning and Research Cooperative System registry (SPARCS) to obtain further information like dates of admission, surgery, discharge, and death. Subjects were eligible for inclusion if they had multivessel disease (defined as severe stenosis [≥ 70%] in at least 2 diseased major epicardial coronary arteries) and if they had undergone either PCI with implantation of an everolimus-eluting stent or CABG. Subjects were excluded if they had revascularization within 1 year before index procedure; previous cardiac surgery; severe left main coronary artery disease (degree of stenosis ≥ 50%); PCI with a stent other than an everolimus-eluting stent; myocardial infarction without 24 hours before the index procedure; and unstable hemodynamics or cardiogenic shock.
Main outcome measures . The primary outcome of the study was all-cause mortality. Various secondary outcomes included rates of myocardial infarction, stroke, and repeat vascularization.
Main results . Among 116,915 patients assessed for eligibility, 82,096 were excluded. Among 34,819 who met inclusion criteria, 18,446 were included in the propensity score–matched analysis. With a 1:1 matching algorithm, 9223 were in the PCI with everolimus-eluting stent group and 9223 were in the CABG group. Short-term outcomes (in hospital or ≤ 30 days after the index procedure) favored PCI with everolimus-eluting stents over CABG, with a significantly lower risk of death (0.6% vs. 1.1%; hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.35 to 0.69; P < 0.002) as well as stroke (0.2% vs 1.2%; HR, 0.18; 95% CI, 0.11 to 0.29; P < 0.001). The 2 groups had similar rates of myocardial infarction in the short-term (0.5% and 0.4%; HR, 1.37; 95% CI, 0.89 to 2.12; P = 0.16). After a mean follow-up of 2.9 years, there was a similar annual death rate between groups: 3.1% for PCI and 2.9% for CABG (HR, 1.04; 95% CI, 0.93 to 1.17; P = 0.50). PCI with everolimus-eluting stents was associated with a higher risk of a first myocardial infarction than was CABG (1.9% vs 1.1% per year; HR, 1.51; 95% CI, 1.29 to 1.77; P < 0.001). PCI with everolimus-eluting stents was associated with a lower risk of a first stroke than CABG (0.7% vs. 1.0% per year; HR, 0.62; 95% CI, 0.50 to 0.76; P < 0.001). Finally, PCI with everolimus-eluting stents was associated with a higher risk of a first repeat-revascularization procedure than CABG (7.2% vs. 3.1% per year; HR, 2.35; 95% CI, 2.14 to 2.58; P < 0.001).
Conclusion. In the setting of newer stent technology with second-generation everolimus-eluting stents, the risk of death associated with PCI was similar to that associated with CABG for multivessel coronary artery disease. In the long-term, PCI was associated with a higher risk of myocardial infarction and repeat revascularization, whereas CABG was associated with an increased risk of stroke. In the short-term, PCI had lower risks of both death and stroke.
Commentary
Coronary artery disease is a major public health problem. For patients for whom revascularization is deemed to be appropriate, a choice must be made between PCI and CABG. In previous studies that compared PCI and CABG, CABG was shown to have less need for repeat revascularizations as well as mortality benefits [1–3]. However, these prior studies compared CABG with older generations of stents. In the past decade, stent technologies have improved, as the bare-metal stent era gave way to the first generation of of drug-eluting stents (with sirolimus or paclitaxel), to be followed by second-generation drug-eluting stents (with everolimus or zotarolimus) [4].
In this article, Bangalore and colleagues addressed the issue of whether the use of second-generation drug-eluting stents close the outcome gap that favors CABG over PCI in patients with multivessel coronary artery disease. In patients who were considered to have had complete revascularization performed during PCI (ie, revascularization of all major vessels with clinically significant stenosis), they noted mitigation of the outcome differences between the PCI group and the CABG group. They conclude that the decision-making process by patients and their providers regarding revascularization be placed in the context of individual values and preferences.
One major limitation is that the study is an observational study from registry data. Despite the use of sophisticated statistical techniques including propensity score matching to adjust for confounders that are implicit in any nonrandomized comparison of treatment strategies, observational studies suffer from the definitely proof of causality. These limitations are especially important when the two groups being compared have modest differences in outcome.
Applications for Clinical Practice
This observational study, together with a recent randomized clinical trial in which CABG was compared with PCI with the use of everolimus-eluting stents from the BEST trial [5], provided new insights of the 2 revascularization strategies. Clinicians should engage and empower patients with a shared decision-making approach. The early hazard of CABG in stroke and death may be unacceptable to some patients, whereas others might want to avoid the later hazards of PCI in repeat procedure or having a myocardial infarction. Until a definitive study is available, patients should be informed of the best current knowledge of the pros and cons of the two revascularization strategies.
—Ka Ming Gordon Ngai, MD, MPH