Impact of calcified bifurcation lesions in patients undergoing percutaneous coronary intervention using drug-eluting stents: Results from the COronary BIfurcation Stent (COBIS) II registry

Aims: Few data regarding clinical outcomes according to severity of calcification in patients with coronary bifurcation target lesions are available. We therefore aimed to evaluate the clinical outcomes according to severity of calcification in patients with coronary bifurcation target lesions after percutaneous coronary intervention (PCI) with drug-eluting stents (DES) using a large-scale multicentre Korean registry. Methods and results: This prospective, multicentre, observational registry enrolled 2,897 patients undergoing PCI with DES for coronary bifurcation lesions. We compared target lesion failure (TLF), defined as a composite of cardiac death, non-fatal myocardial infarction (MI), and target lesion revascularisation (TLR), according to severity of calcification in coronary bifurcation target lesions, assessed by an angiographic core laboratory using quantitative coronary angiography. Moderate or severe calcification of target bifurcation lesions was observed in 608 (20.9%) patients. During a median follow-up period of 36 months, moderate or severe calcification increased the adjusted risks of TLF (hazard ratio [HR] 1.31, 95% confidence interval [CI]: 1.03-1.68, p=0.031), TLR (HR 1.36, 95% CI: 1.04-1.79, p=0.027), and revascularisation (HR 1.39, 95% CI: 1.09-1.78, p=0.009). However, it was not associated with an increased risk of cardiac death, MI, or stent thrombosis. Conclusions: Moderate or severe calcification of coronary bifurcation lesions is not uncommon and is associated with unfavourable long-term clinical outcomes, driven mainly by an increased frequency of repeat revascularisation.