Cardiac Troponin Elevation Beyond Type 1 Myocardial Infarction: A Systematic Review of Prognostic Significance and...

Cardiac troponin elevation is central to the diagnosis of myocardial injury, but its clinical interpretation remains challenging when type 1 myocardial infarction is absent. This systematic review evaluated the clinical and prognostic significance of elevated cardiac troponin in adults without type 1 myocardial infarction, with particular emphasis on type 2 myocardial infarction, critical illness-related myocardial injury, suspected acute coronary syndrome populations with minor myocardial injury, and acute or chronic heart failure-related myocardial injury. A systematic search of PubMed/MEDLINE, Scopus, and Web of Science identified six eligible clinical studies. The included evidence comprised prospective and retrospective cohort studies, secondary biomarker analyses of randomized trials, and trial-derived heart failure cohorts. Across heterogeneous clinical settings, troponin elevation was consistently associated with adverse outcomes, including all-cause mortality, cardiovascular mortality, heart failure hospitalization, cardiovascular death or heart failure rehospitalization, and greater clinical severity. In type 2 myocardial infarction and critical illness, troponin elevation identified high-risk patients despite the absence of classic plaque-rupture acute coronary syndrome. In heart failure populations, troponin appeared to function as a dynamic marker of myocardial stress, residual risk, and treatment-responsive injury. High-sensitivity assays further suggest that troponin may convey prognostic information across a continuum rather than only above binary diagnostic thresholds. These findings support a phenotype-based approach in which troponin elevation outside type 1 myocardial infarction is interpreted according to mechanism, clinical context, biomarker trajectory, and follow-up needs. Although current evidence does not define a uniform treatment pathway, it indicates that troponin-positive patients without type 1 myocardial infarction should not be considered low risk solely because acute coronary syndrome has been excluded. Future prospective studies should determine which troponin-positive phenotypes benefit most from structured cardiovascular reassessment, targeted investigation, and post-discharge surveillance.