Critical Diagnostics' Presage ST2 Assay effectively risk-stratifies chronic heart failure patients

Critical Diagnostics, the exclusive developer of the Presage® ST2 Assay, announces the publication of the Penn Heart Failure Study (PHFS) in an advance e-publication of the January 19, 2010 edition of Circulation: Heart Failure. The results of this study demonstrated that ST2 levels not only predict outcomes for ambulatory outpatients with chronic heart failure, they more effectively risk-stratify such patients.

“By using the Presage ST2 Assay, clinicians may be able to target heart failure therapy more appropriately.”

In the multi-center cohort of 1,141 heart failure patients, those with high levels of ST2 were significantly more likely to have a heart transplant or to die during the three-year follow-up period than those with low levels of ST2. By identifying those patients at highest risk, physicians can more appropriately tailor treatments to each patient and maximize utility of scarce and expensive health care resources.

Dr. Bonnie Ky and colleagues found that patients in the highest ST2 tertile had a higher risk of adverse outcomes compared to the lowest tertile, with an unadjusted hazard ratio (HR) of 3.2 (p < 0.0001) that remained significant after multivariable adjustment (adjusted HR 1.9; p = 0.002). With each doubling of ST2, there was a 40 - 50% increased risk of death or cardiac transplantation in fully adjusted models.

The patients, who had been recruited from three tertiary-care centers (University of Pennsylvania, Case Western University, and University of Wisconsin), were followed for a median of 2.8 years. There were 267 adverse events over the period (23% of patients), defined as the combined endpoint of death or cardiac transplantation. ST2 levels were measured at baseline from a blood sample taken at the enrollment of each patient into the study. The investigators conducted statistical analyses to predict outcomes by examining clinical presentation as well as the cardiac biomarkers ST2 and NT-proBNP. The clinical presentation data was also used to determine a risk score for each patient using the validated Seattle Heart Failure Model (SHFM), and to confirm the independent clinical utility of ST2 over and above that of the prognostic clinical parameters of the SHFM and NT-proBNP.

"The researchers also found that more than one in seven chronic heart failure patients can be more appropriately risk-stratified when using ST2 and NT-proBNP in addition to the Seattle Heart Failure Model," said Pat Arensdorf, Chief Executive Officer of Critical Diagnostics. "By using the Presage ST2 Assay, clinicians may be able to target heart failure therapy more appropriately."

PHFS has provided the largest study of ST2 ever performed in chronic, stable heart failure. The findings of this research support the utility of ST2 for identification of high risk patients who may benefit from more aggressive therapy.