ST2 in Stable and Unstable Ischemic Heart Diseases

Circulating suppression of tumorigenicity 2 (ST2) predicts cardiovascular outcomes and mortality in ischemic heart disease (IHD). ST2 does not correlate with traditional risk indicators as closely as N-terminal pro–brain natriuretic peptide (NT-proBNP) and is only weakly correlated with other biomarkers, indicating distinct pathways for stimulus and release. Although of little diagnostic utility in IHD, ST2 does offer prognostic information. In ST elevation myocardial infarction, ST2 levels increase to peak above the normal reference range (within 6 to 18 hours of symptom onset) in about half of patients. Levels in the upper quartile observed in IHD independently predict cardiovascular death and heart failure with an approximate doubling of risk. Similar but weaker associations have been reported in non–ST elevation myocardial infarction, in which ST2 predicts short-term (30-day) and long-term (>1-year) death and heart failure independent of clinical indicators, but these relations are lost if Global Registry of Acute Coronary Events (GRACE) score and NT-proBNP are added to multivariate models. Early postinfarction levels of ST2 (i.e., <24 hours after admission) have the greatest prognostic utility. Early postinfarction ST2 levels and change over 24 weeks are related to infarct extent and remodeling to a similar extent as NT-proBNP and aldosterone, and ST2 may have a significant pathophysiological role in these postinfarction processes. In long-term follow-up of stable IHD, ST2 is predictive of all-cause and cardiovascular mortality independent of accepted clinical indicators and other biomarkers, including NT-proBNP, high-sensitivity C-reactive protein, interleukin-6, high-sensitivitiy cardiac troponin T, and galectin-3. In conclusion, ST2 in combination with NT-proBNP consistently improves risk stratification compared with either marker alone.