Comparison of percutaneous coronary intervention of native coronary artery versus bypass graft in patients with prior coronary artery bypass grafting.

Background: Large number of patients with prior coronary artery bypass grafting (CABG) need repeat revascularization yearly, and percutaneous coronary intervention (PCI) is the optimal treatment strategy for such patients. However, it is still controversial whether PCI of native coronary artery or bypass graft is more beneficial. The aim of the study was to compare the clinical outcomes between native coronary artery vs. bypass graft PCI in patients with prior CABG. Methods: A total of 1,276 patients with prior CABG who underwent index PCI of native coronary artery (n=1,072) or bypass graft (n=204) were retrospectively examined. Patients were divided into native group and graft group according to the target vessel. The outcomes of the two groups were compared by using inverse probability of treatment weighting (IPTW) and Cox regression analysis. The primary endpoint was the composite of major adverse cardiac and cerebrovascular events (MACCEs), which included all-cause death, non-fatal stroke, non-fatal myocardial infarction (MI), or target vessel revascularization (TVR). Results: Compared with native group, patients in graft group had higher risk of slow-flow/no-reflow phenomenon (1.5% vs. 0.1%, P=0.011 before IPTW, and 2.2% vs. 0.1%, P<0.001 after IPTW) and peri-procedural stroke (0.3% vs. 0, P=0.021 after IPTW). During a median follow-up period of 43 months, there was similar risk of MACCE between two groups. Notably, patients in graft group had a significantly higher incidence of non-fatal MI compared with native group regardless with or without IPTW (7.8% vs. 3.8%, P=0.018 and 8.3% vs. 3.9%, P=0.030, separately). After adjusting for confounding by using Cox regression, bypass graft PCI was associated with a higher risk of non-fatal MI (HR: 2.091, 95% CI: 1.069-4.089; P=0.031), but similar results in MACCE (HR: 1.077, 95% CI: 0.817-1.419; P=0.599) compared with native group. Conclusions: This study found that native coronary artery might be preferred for PCI in patients with prior CABG because of lower rates of slow-flow/no-reflow, peri-procedural stroke, and non-fatal MI at follow-up.