Cardiac Troponin Elevation in Patients Without a Specific Diagnosis.

BACKGROUND: Cardiac troponin (cTn) elevation is a common finding in acutely admitted patients, even in the absence of acute coronary syndrome. In some of these patients, no etiology of cTn elevation can be identified. The term troponinemia is sometimes used to describe this scenario.

OBJECTIVES: This study aimed to investigate the associations of cTn levels with clinical findings and long-term outcome in acutely admitted patients with suspected acute coronary syndrome who had been discharged without a specified diagnosis.

METHODS: Retrospective registry-based cohort study investigating 48,872 patients (SWEDEHEART [Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies] registry). Patients were stratified into cohorts with cTn levels less than or equal to the assay-specific 99th percentile and separated by assay-specific cTn tertiles in case of higher levels.

RESULTS: A cTn level >99th percentile was noted in 9,800 (20.1%) patients. The prevalence of cardiovascular risk factors as well as cardiovascular and noncardiovascular comorbidities increased across higher cTn strata. In total, 7,529 (15.4%) patients had a major adverse event (MAE), defined as the composite of all-cause mortality, myocardial infarction, readmission for heart failure, or stroke (median follow-up 4.9 years). MAE risk was associated with higher cTn strata (hazard ratio for highest assay-specific cTn tertile: 2.59; 95% confidence interval: 2.39 to 2.80; hazard ratio in patients without cardiovascular comorbidities, renal dysfunction, left ventricular dysfunction, or significant coronary stenosis: 3.57; 95% confidence interval: 2.30 to 5.54).

CONCLUSIONS: cTn elevation is associated with cardiovascular and noncardiovascular comorbidities and predicts major adverse events in acutely admitted patients, in whom no definite diagnosis could have been established. The term troponinemia is trivializing and should be avoided. Instead, careful work-up is required in these patients.