The triglyceride-glucose index and intramyocardial hemorrhage identify a high-risk phenotype in STEMI

The prognostic value of combining the triglyceride-glucose (TyG) index and intramyocardial hemorrhage (IMH) in STEMI is unclear. We assessed their individual and combined association with major adverse cardiovascular events (MACE).

This retrospective study included 456 STEMI patients undergoing primary PCI. TyG index was calculated from admission blood samples; IMH was assessed by cardiac magnetic resonance. The primary outcome was MACE (median follow-up 4 years). Multivariable Cox regression, restricted cubic spline analysis, incremental prognostic assessment (C-index, NRI, IDI), and interaction testing were performed.

MACE increased across TyG tertiles (15.79% → 27.63% → 43.42%). The highest tertile remained independently associated with MACE (adjusted HR 1.86; 95% CI 1.09-3.20). Patients with high TyG (≥8.66) plus IMH had the worst prognosis (HR 4.00; 95% CI 2.49-6.39; P < 0.001), far exceeding either factor alone. Adding the combined variable to a base model improved discrimination and reclassification (C-index 0.640 → 0.658; NRI = 0.216, P = 0.020; IDI = 0.025, P = 0.008). Neither additive nor multiplicative interaction was significant, and results were consistent in diabetic and non-diabetic patients. A significant interaction was observed between TyG index and infarct location (P for interaction = 0.037), with a stronger effect in anterior (HR 1.59) than non-anterior infarction (HR 0.75).

The TyG index independently predicts long-term MACE in STEMI. Combining high TyG with IMH identifies a high-risk phenotype with a 4.0-fold higher MACE risk and incremental prognostic value. The TyG effect is stronger in anterior infarction, suggesting infarct location should be considered in metabolic risk stratification.