Abstract 4334: Do We Need More than One Biomarker for Risk Prediction in Acute Dyspnea? Concentrations of ST2 Strongly Predict 4 Year Prognosis in Acutely Dyspneic Patients with Very Low NT-proBNP Values
Objectives: Measurement of NT-proBNP may be used to stratify risk for hazard in patients with acute dyspnea. Serum levels of the interleukin receptor family member ST2 strongly predict outcome in acute heart failure (HF) patients. The ST2-gene has also shown to be upregulated in inflammatory lung diseases. However, the prognostic value of ST-2 in patients with very low concentrations of NT-proBNP remains unclear.
Methods: We measured NT-proBNP and ST2 levels among 599 acutely dyspneic patients presenting to an urban emergency department. Vital status at 4 years was the primary outcome measure for the present study. The optimal NT-proBNP cut point for predicting death at this time point was 300 ng/L.
Results: NT-proBNP levels were <300 ng/L in 263 patients; of these, 31 patients (12%) had died after 4 years. Median ST-2 levels were higher in those who died (0.39 ng/mL) vs. those who survived (0.10 ng/mL; P <.001). Among those with a very low NT-proBNP, mortality rates were considerably higher among those with an ST2 above the optimal cut-point of 0.15 ng/mL (25.3% vs 4.2%; P <.001), with early and sustained rates of death out to 4 years after enrollment (Figure⇓). In an age adjusted Cox proportional hazards analysis, an ST2 >.15 ng/mL strongly predicted 4 year mortality among those with a very low NT-proBNP (HR 5.63; 95% CI=2.50 –12.7; P <.001).
Conclusion: Among acutely dyspneic patients otherwise conventionally considered “low risk” by NT-proBNP testing, ST2 results strongly predict fatal outcomes at least to 4 years.