Abstract Body (Do not enter title and authors here): Background: The inflammatory response plays a crucial role in various aspects of acute coronary syndrome. However, there is limited data associating a validated inflammation risk score and overall mortality prediction in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI).

Hypothesis: We hypothesize that patients with STEMI exhibiting a severe inflammatory profile undergoing primary PCI have a higher incidence of all-cause mortality within 30 days.

Methods: This retrospective cohort study obtained from the Coronary Care Unit of a tertiary center in Mexico, included 2,473 patients with acute STEMI who underwent pPCI between October 2005 and December 2023. We employed an inflammation score which comprises: high-sensitivity C-reactive protein (≥ 13.0 mg/L), white blood cell count (≥ 9.3 x10³/µL), and serum albumin level (≤ 3.6 g/dL) upon admission. We categorized systemic inflammation into four distinct levels. Mortality risk across these cohorts was compared using the Kaplan-Meier method.

Results: The cohort included 248, 1035, 851, and 339 patients with no, mild, moderate, and severe inflammation, respectively. A significant proportion of the sample (76.3%) displayed mild to moderate inflammation, underscoring its prevalence in the studied population. Notably, 13.7% exhibited severe inflammation, potentially indicating high-risk groups. At the 30-day follow-up, patients with severe inflammation exhibited the highest mortality rates (Image 1; 1.2% vs. 2.5% vs. 5.4% vs. 13%, respectively; Log-rank p<0.001). The hazard ratio for mild inflammation is 2.07 (95% CI, 0.605-7.08; p=0.2), for moderate inflammation it is 4.47 (95% CI, 1.36,-14.69; p<0.05), and for severe inflammation it is 10.73 (95% CI, 3.65-31.27; p<0.0001) compared to the no inflammation group.

Conclusions: The observed prevalence of inflammation across the studied population suggests a prevailing inflammatory trend influenced by underlying medical conditions, social factors and the STEMI process itself. We suggest a noteworthy association between heightened systemic inflammation during the acute phase of STEMI and increased overall 30-day mortality risk in patients undergoing pPCI.