AbstractObjectivesWe aimed to evaluate the prognostic significance of the SYNTAX score (SS) and SYNTAX score II (SS‐II) in a contemporary real‐world cohort of myocardial infarction (MI) patients treated with percutaneous coronary intervention (PCI).BackgroundThe role of SS and SS‐II in the prognostic stratification of patients presenting with MI and undergoing PCI has been poorly investigated.MethodsThis study included MI patients treated with PCI from January 2015 to April 2020 at the University Hospital of Salerno. Patients were divided into tertiles according to the baseline SS and SS‐II values. The primary outcome measure was all‐cause mortality at long‐term follow‐up; secondary outcome measures were cardiovascular (CV) death and MI.ResultsOverall, 915 patients were included in this study. Mean SS and SS‐II were 16.1 ± 10.0 and 31.6 ± 11.5, respectively. At propensity weighting adjusted Cox regression analysis, both SS (hazard ratio [HR]: 1.02; 95% confidence interval [CI]: 1.02−1.06; p = 0.017) and SS‐II (HR: 1.08; 95% CI: 1.07−1.10; p < 0.001) were significantly associated with the risk of all‐cause mortality at long‐term follow‐up; both SS (HR 1.04; CI 1.01−1.06; p < 0.001) and SS‐II (HR 1.08; CI 1.06−1.10; p < 0.001) were significantly associated with the risk of CV death, but only SS‐II showed a significant association with the risk of recurrent MI (HR 1.03; CI 1.01−1.05; p < 0.001). At 5 years, SS‐II showed a significantly higher discriminative ability for all‐cause mortality than SS (area under the curve: 0.82 vs. 0.64; p < 0.001). SS‐II was able to reclassify the risk of long‐term mortality beyond the SS (net reclassification index 0.88; 95% CI: 0.38−1.54; p = 0.033).ConclusionsIn a real‐world cohort of MI patients treated with PCI, SS‐II was a stronger prognostic predictor of long‐term mortality than SS.