ST2 is a member of the interleukin-1 receptor family that is up-regulated in conditions associated with increased myocardial strain. ST2 has been shown to be independently predictive of adverse outcome in heart failure and ST-segment elevation myocardial infarction, but its prognostic value in non–ST-elevation acute coronary syndrome (NSTE-ACS) has not been established.

We measured ST2 at randomization and after 24, 48, and 72 hours in 403 NSTE-ACS patients from the GUSTO IV study, and studied its kinetics and its associations to clinical baseline factors and 1-year mortality.

Median ST2 levels decreased from 28.4 U/mL at randomization to 21.8 U/mL at 72 hours (P < .001). Peak levels were noted 6 to 17 hours after symptom onset. Randomization ST2 levels were independently associated to N-terminal pro-B-type natriuretic peptide but otherwise exhibited only weak relations to cardiovascular risk factors and comorbidities, and biomarkers of myocardial necrosis or inflammation. ST2 was related to 1-year mortality independently of clinical risk indicators (odds ratio 2.3 [95% CI 1.1-4.6], P = .03) but lost its predictive value after additional adjustment for prognostic biomarkers, in particular N-terminal pro-B-type natriuretic peptide.

ST2 levels are elevated early in NSTE-ACS and predict 1-year mortality. Our data indicate that ST2 represents an interesting novel pathophysiologic pathway in the setting of ischemia-related myocardial dysfunction. However, future prospective evaluations in larger populations are needed before the clinical utility of ST2 can be determined.