<p>Evidence regarding the predictive ability of the triglyceride-glucose (TyG) index for all-cause and cardiac mortality in patients with coronary heart disease (CHD) following percutaneous coronary intervention (PCI) remains limited. We determined whether TyG value is associated with the mortality risk (all-cause and cardiac death) in CHD patients after PCI. This secondary analysis included 2,533 CHD patients who underwent PCI, using data from the Dryad database. Among included CHD patients, 120 (7.2%) died from any cause and 80 (4.8%) from cardiac causes. Smooth curve analysis revealed that the TyG value was positively correlated with both all-cause and cardiac mortality. After the adjustment for confounding factors was made, a higher TyG level remained independently correlated with all-cause death [OR 1.7 (1.1–2.7)] and cardiac death [OR 1.7 (1.0–3.0)]. ROC analysis showed that a model combining the TyG index with age, sex, and smoking had potential predictive value for all-cause death (AUC = 0.718) and cardiac death (AUC = 0.697). Elevated TyG levels are positively correlated with all-cause and cardiac mortality risk in patients undergoing PCI. A multi-indicator combination may offer better mortality prediction than traditional factors alone. Further clinical studies are warranted to validate these findings.</p>