Impact of the distribution of calcification around the left main coronary artery bifurcation on prognosis after percutaneous coronary intervention

Abstract Backgrounds The presence of true bifurcation lesions (TBL) by Medina classification at the left main coronary artery (LMCA) bifurcation is known to be associated with cardiovascular events after percutaneous coronary intervention (PCI). However, the prognostic impact of the distribution of calcification at LMCA bifurcation has not been adequately investigated. Methods This retrospective study consisted of consecutive patients who were implanted with a second or subsequent generation drug-eluting stent for LMCA bifurcation at a single center from 2014 to 2018. We excluded patients with a protected LMCA and those in whom calcification or stenosis of the LMCA bifurcation could not be assessed. With reference to the Medina classification, the region was divided into three segments (LM, LAD, and LCX). Each segment was assigned a value of 0 (for less than moderate calcification) or 1 (for more than moderate calcification) and expressed as calc (X.X.X). Calc (1.1.1), calc (1.0.1), and calc (0.1.1) were defined as true bifurcation calcification (TBC). The primary endpoint was 3-year target lesion failure (TLF), a composite of cardiac death, target vessel myocardial infarction, or clinically driven target lesion revascularization. Results Of 498 patients in this analysis, the mean age was 73 years, males accounted for 78% overall, acute coronary syndrome 31% overall, and TBL 42% overall. Moderate or severe calcification at any site around the LMCA bifurcation was observed in 184 (37%). In order of frequency, calc (1.1.0) in 70 (14%), calc (1.1.1) in 58 (12%), calc (0.1.0) in 43 (9%), calc (0.1.1) in 11 (2%), and calc (1.0.1) in 2 (0.4%), while calc (1.0.1) and calc (1. 0.0) were not present. TBC accounted for 14% overall. Patients with TBC at LMCA bifurcation had a higher incidence of 3-year TLF (Log-rank P <0.001; Figure1). Multivariable logistic regression, including age, acute coronary syndrome, maintenance hemodialysis, SYNTAX score ≥33, TBL, and TBC in the model as covariates, TBC was significantly associated with the primary endpoint (adjusted odds ratio 3.4, 95% confidence interval 1.6-7.2, P=0.013). In contrast, a significant association between TBL and the primary endpoint was not observed (adjusted odds ratio 1.5, 95% confidence interval 0.8-2.8, p=0.206). Conclusion Even after adjusting the presence of TBL at LMCA bifurcation, the presence of TBC at LMCA bifurcation was significantly associated with the 3-year TLF.