Splenic tissue alterations in ST-elevation myocardial infarction: determinants and prognostic implications

AIMS: While previous studies suggest a cardio-splenic axis involving splenic activation and systemic inflammation, presence and clinical significance of splenic tissue alterations on cardiac magnetic resonance (CMR) in ST-segment-elevation myocardial infarction (STEMI) remain unclear. This study aims to identify determinants of splenic T1 patterns in STEMI and explore their association with adverse outcomes. METHODS AND RESULTS: This retrospective study enrolled STEMI patients undergoing CMR within 10 days after primary percutaneous coronary intervention (April 2017-October 2024). CMR evaluated infarction patterns, myocardial function, native splenic T1 times and extracellular volume (ECV). Major adverse cardiovascular events (MACE) included cardiovascular death, heart failure and myocardial re-infarction. Results were validated in a separate cohort. Associations between variables and outcomes were evaluated using Cox regression. The development and validation cohorts comprised 1037 (median age 60; 872 men) and 252 (median age 59; 212 men) patients, respectively. Over a median follow-up of 38 and 30 months, 207 and 40 MACE occurred. In multivariable Cox regression, both elevated splenic T1 z-score [adjusted hazard ratio (HR) 1.58] and splenic ECV (adjusted HR 1.22) independently predicted MACE, driven primarily by heart failure and non-target vessel re-infarction. The model combining clinical and conventional myocardial imaging risk factors with splenic T1 z-score demonstrated best discrimination among all tested models (development C index = 0.87; validation C index = 0.85). CONCLUSION: Elevated splenic T1 z-score and ECV assessed by CMR after STEMI independently predicted MACE, mainly because of higher risk of heart failure and non-target vessel re-infarction, providing incremental prognostic value over traditional clinical and imaging risk markers.