Long-term outcome of diabetic patients after unprotected left main percutaneous coronary interventions

Abstract Background Diabetes mellitus (DM) represents an elevated risk in terms of percutaneous coronary intervention (PCI), especially in patients with significant left main (LM) disease. Purpose Our aims were to investigate the 60-month mortality and event-free survival of consecutive patients with DM undergoing unprotected LM PCI at our centre and sought to determine the independent predictors of event-free survival. Methods We included all patients undergoing unprotected LM PCI at our tertiary care centre between 1 January 2007 and 31 December 2014. The primary endpoint was the composite of all-cause mortality, myocardial infarction, and target lesion revascularization at 60 months. Survival curves were constructed using the Kaplan-Meier non-parametric estimator. ROC analysis was used to investigate the predictive power of conventional risk scores (SYNTAX, SYNTAX II, EuroSCORE II, additive and logistic EuroSCORE, ACEF, GRACE 2). Independent predictors were determined by univariate and multivariate analysis. Results A total of 513 patients (mean age 68 ± 12 years, 64% male) underwent unprotected LM PCI during this period, among these 310 (60%) were non-diabetic (non-DM) and 203 (40%) were diabetic (DM). In terms of indication, 157 (31%) elective and 356 (69%) acute LM PCI were performed. There was no significant difference between the non-DM and DM groups in terms of acute indication (218 (70%) vs. 138 (68%), p=0.574). Within the DM group, 135 (67%) were treated with oral antidiabetics (OAD) and 68 (33%) were treated with insulin (IDM). The mean survival (34.6 vs. 39.7 vs. 43.1 months, p=0.003) and event-free survival (29.3 vs. 34.7 vs. 39.3 months, p=0.001) were significantly lower in the IDM and OAD groups compared to non-DM, respectively. Of the risk scores, the SYNTAX score was the most predictive in diabetic patients (AUC=0.767). Based on the SYNTAX score, diabetic patients with a low SYNTAX score (<23) had less events (59% vs. 66%, p=0.043) than those having a moderate/high SYNTAX score (≥23). LVEF (HR 0.976; 95% CI, 0.965-0.987, p<0.001), right coronary artery occlusion (HR 2.031; 95% CI, 1.346-3.064, p=0.001), acute coronary syndrome (HR 1.861; 95% CI, 1.252-2.767, p=0.002), use of FFR (HR 0.481; 95% CI, 0.265-0.871, p=0.016), true bifurcation lesion (HR 1.559; 95% CI, 1.068-2.277, p=0.021) and newer DES generation (HR 0.706; 95% CI, 0.568-0.877, p=0.002) were predictors of event-free survival in diabetics by univariate analysis. Glomerular filtration rate (HR 0.982; 95% CI, 0.973-0.991, p<0.001) emerged as an independent predictor according to multivariate analysis. Conclusion Consecutive diabetic patients with significant unprotected LM stenosis have poor long-term outcome after LM PCI. Anatomical complexity of the lesions is a significant predictor of event-free survival. Careful intervention planning and the use of appropriate tools can improve the outcome in this high-risk population.