Long-term impact of diabetes on mortality in patients undergoing unprotected left main PCI: a propensity score-matched analysis

Abstract Background The optimal revascularisation strategy for left main coronary artery (LMCA) has been the subject of longstanding debate. Coronary artery bypass grafting (CABG) has historically been considered the standard of care, especially in the setting of concomitant diabetes. However, recent ESC guidelines reflect the growing recognition of percutaneous coronary intervention (PCI) as a valuable therapeutic option when surgery is deemed excessively high-risk. Despite evidence comparing PCI and CABG, the impact of diabetes on long-term mortality in patients undergoing PCI for LMCA remains unclear. Purpose To address gap in evidence, our study, based on the largest single-center registry of LMCA PCI in Poland, aimed to provide a comprehensive assessment of the relationship between diabetes and long-term survival following PCI in a real-world setting. Methods We analyzed 998 patients who underwent LMCA PCI between December 27, 2007, and February 21, 2022. Diabetes and insulin dependence were defined based on medical history, prior records, and prescribed treatment. The primary endpoint was all-cause mortality at the longest available follow-up (mean observation 4.2 years), available for all patients. Survival analysis was conducted in both the overall cohort and a propensity score-matched (PSM) population using one-to-one matching. Moderation effects and differences between subgroups were analysed in predefined groups of PSM cohort. Results Final cohort included 752 patients undergoing unprotected LMCA PCI. The median age was 71 (63-79) years; 212 (28.2%) were women, and 250 (33.2%) had diabetes. In the overall cohort, diabetes was associated with worse prognosis (HR 1.35, 95% CI 1.03–1.76, P=0.03). PSM resulted in 214 well-balanced pairs (median age 73 years (66-79)), with no significant difference in all-cause mortality between groups (adjusted HR 1.27, 95% CI 0.91–1.77, P=0.16). Subgroup analysis after PSM showed worse outcomes for patients with diabetes undergoing two-stent angioplasty (HR 3.70, 95% CI 1.64–8.34, P=0.002) and elective PCI (HR 2.07, 95% CI 1.29–3.31, P=0.003). Conversely, among patients presenting with myocardial infarction, diabetics had better survival than the control group (HR 0.56, 95% CI 0.35–0.90, P=0.02). No significant differences in outcomes were observed in patients with heart failure (HR 1.29, 95% CI 0.88–1.89, P=0.19), chronic kidney disease (HR 1.08, 95% CI 0.69–1.71, P=0.19), intravascular imaging use (HR 1.38, 95% CI 0.70–2.71, P=0.35), or concomitant multivessel disease (HR 1.14, 95% CI 0.75–1.73, P=0.53). Conclusions Diabetes was not associated with increased overall mortality following LMCA PCI. Sensitivity analyses showed worse survival outcomes in diabetic patients treated with a two-stent technique and undergoing non-emergency PCI. These findings support overall safety of PCI for LMCA in diabetics and highlight the need for randomized trials, especially investigating indicated high-risk subgroups.Graphical Abstract Predefined subgroups analysis