Time-dependent prognostic performance of inflammatory biomarkers after AMI: results from the INFINITY study.

BACKGROUND

Inflammatory biomarkers derived from routine blood counts reflect immune activation in acute myocardial infarction (AMI). However, their temporal prognostic relevance after AMI remains uncertain.

METHODS

This prospective sub-study of the INFINITY trial (NCT06065514) included 100 consecutive patients with AMI. Five admission-derived inflammatory biomarkers were evaluated: systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), and platelet-to-lymphocyte ratio (PLR). Major adverse cardiovascular events (MACEs) were assessed cumulatively during hospitalization and at 1, 6, and 12 months. Associations were evaluated using non-parametric tests, receiver operating characteristic analysis, Kaplan-Meier survival curves, and parsimonious logistic regression adjusted for GRACE score.

RESULTS

No inflammatory biomarker predicted in-hospital events. At 1-month, elevated SIRI was associated with MACEs (p = 0.017; AUC 0.77), identifying early post-discharge vulnerability. At 6 months, SII (p = 0.036), NLR (p = 0.031), and SIRI (p = 0.032) were associated with adverse outcomes with moderate discrimination (AUC ≈0.69). Associations were attenuated after adjustment for the GRACE score. Nobiomarker demonstrated consistent prognostic value at 12 months.

CONCLUSIONS

Admission-derived inflammatory biomarkers show a dynamic prognostic profile after AMI.SIRI identifies early risk, while broader inflammatory activation relates to mid-term outcomes, suggesting complementary value for biomarker-based risk stratification.