Soluble ST2 reflects hemodynamic stress in non-ischemic heart failure

Elevated levels of soluble ST2 (sST2) are associated with adverse outcome in heart failure. A change in sST2 levels has also been shown to presage outcome. In vitro, ST2 expression is induced by myocardial stress and pro-inflammatory stimuli. The determinants of sST2 levels in vivo, and how they vary with clinical status over time, have not been well described. In a cohort of patients with non-ischemic heart failure, we aimed to assess the association between sST2-levels and hemodynamic parameters reflecting right and left ventricular pre- and afterload, and how these vary with time and clinical status.

We prospectively recruited 102 patients with a left ventricular ejection fraction of 26 ± 10% and a diagnosis of idiopathic dilated cardiomyopathy based on patient history, clinical examination, echocardiography and coronary angiography. Patients went through extensive baseline work-up and were re-examined after one year. Subsequently, heart transplantations and deaths were recorded. Determinants of sST2 were analyzed at baseline and after one year. Soluble ST2 was measured with a highly sensitive immunoassay.

Soluble ST2 levels were associated with hemodynamic parameters, but these associations were attenuated with clinical improvement. Soluble ST2 was elevated in patients with severe symptoms, but did not vary with etiology, viral presence or the amount of myocardial fibrosis. Heart rate and right atrial pressure remained independent predictors of sST2 on multiple regression analysis.

Our results imply that in non-ischemic heart failure, sST2 reflects hemodynamic stress rather than pathogenic processes in the myocardium.