Prognostic utility of ST2 in patients with acute dyspnea and preserved left ventricular ejection fraction

BACKGROUND: Soluble ST2 (sST2), an interleukin-1 receptor family member, is an emerging risk indicator for patients with cardiovascular disease. We evaluated the prognostic role of sST2 for patients presenting to the emergency department with acute dyspnea, with a focus on those with preserved left ventricular ejection fraction (LVEF ≥50%), as risk stratification is often most complex in this subgroup. METHODS: We conducted a post hoc analysis of 387 patients [39% female, mean (SD) age 57.6 (14.5) years] presenting to the emergency department with dyspnea and followed for 1 year (97% complete follow-up). We examined clinical data, concentrations of serum biomarkers [sST2, amino-terminal pro-B-type natriuretic peptide (NT-proBNP)], and transthoracic echocardiography. RESULTS: Patients had a median sST2 concentration of 38.4 U/mL [interquartile range (IQR) 25.5-64 U/mL]. Forty-six patients (12%) died during follow-up. Log sST2 [hazard ratio (HR) (95% CI) 2.85 (2.04-3.99), P<0.001rsqb] and log NT-proBNP [1.28 (1.13-1.45), P < 0.001] concentrations were significant predictors of mortality at 1 year. After multivariate adjustment, only sST2 remained predictive of mortality [per log: 2.14 (1.37-3.38), P = 0.001]. In the subpopulation of individuals with normal systolic function (n = 200), only sST2 continued to predict mortality after multivariate adjustment [per log: 2.57 (1.12-5.91), P = 0.03]. Only NT-proBNP, but not sST2, concentrations correlated with multiple echocardiographic indices of left ventricular diastolic function. CONCLUSIONS: sST2 is a strong predictor of mortality in patients presenting with acute dyspnea, particularly those with preserved LVEF, and may be useful for triage and risk stratification of this challenging group.