Impact of drug-eluting stents on the comparative effectiveness of coronary artery bypass surgery and percutaneous coronary intervention.

BACKGROUND: Drug-eluting stents (DES) have largely replaced bare-metal stents (BMS) for percutaneous coronary intervention (PCI). It is uncertain, however, whether introduction of DES had a significant impact on the comparative effectiveness of PCI versus coronary artery bypass graft surgery (CABG) for death and myocardial infarction (MI).
METHODS: We identified Medicare beneficiaries aged ≥66 years who underwent multivessel CABG or multivessel PCI and matched PCI and CABG patients on propensity score. We defined the BMS era as January 1999 to April 2003 and the DES era as May 2003 to December 2006. We compared 5-year outcomes of CABG and PCI using Cox proportional hazards models, adjusting for baseline characteristics and year of procedure and tested for a statistically significant interaction (P(int)) of DES era with treatment (CABG or PCI).
RESULTS: Five-year survival improved from the BMS era to the DES era by 1.2% for PCI and by 1.1% for CABG, and the CABG:PCI hazard ratio was unchanged (0.90 vs 0.90; P(int) = .96). Five-year MI-free survival improved by 1.4% for PCI and 1.1% for CABG, with no change in the CABG:PCI hazard ratio (0.81 vs 0.82; P(int) = .63). By contrast, survival-free of MI or repeat coronary revascularization improved from the BMS era to the DES era by 5.7% for PCI and 0.9% for CABG, and the CABG:PCI hazard ratio changed significantly (0.50 vs 0.57, P(int) ≤ .0001).
CONCLUSIONS: The introduction of DES did not alter the comparative effectiveness of CABG and PCI with respect to hard cardiac outcomes.