Abstract 2370: Association of ST2 Levels With Cardiac Structure and Function and Mortality in Outpatients
Introduction: ST2, an interleukin-1 receptor family member, is upregulated in the setting of cardiomyocyte strain. Studies have identified a prognostic cut-point of 30 units/ml for 1 year mortality in acute HF patients. While there is also prognostic value in patients with acute MI and chronic severe HF, the predictive value of ST2 levels in less sick patients are unknown. We sought to determine the clinical and echocardiographic correlates of ST2 levels, and to evaluate their prognostic utility, in outpatients referred for echocardiograms.
Methods: We evaluated 588 outpatients referred for echocardiogram. Subjects were divided into 2 groups based on the optimal ST2 cut-point (28.25 units/ml) derived from ROC curve analysis. All-cause death at 1 year was the primary outcome.
Results: In this cohort with mean age 68±12 years and median ST2 level 19.8 units/ml (interquartile range 15.8–23.7), 25 deaths occurred over 1 year of follow-up (4.3%). Heart rate, creatinine clearance, current use of diuretics, and the presence of right ventricular (RV) hypokinesis were independent predictors of ST2 levels. Patients with high ST2 levels (n=211, 35.9%) had an increased risk of death, with an adjusted hazard ratio (HR) of 2.5 (95% CI 1.1–5.6, p=0.023, Table⇓). At 4 months, no patients with low ST2 had died. Patients with elevated levels of both ST2 and BNP were at considerably increased risk of death compared to those with either none or with only one marker elevated (adjusted HR for both vs. none elevated 4.9, 95% CI 1.1–21.1, p=0.03).
Conclusions: ST2 levels are independent predictors of 1 year mortality in outpatients referred for echocardiograms. The optimal cut-point derived in this cohort, 28.25 unit/ml, is comparable to the previously identified prognostic cut-point of 30 units/ml for sicker patients with acute HF. ST2 may be an especially strong prognostic marker for short-term mortality risk. In addition, ST2 may be an important prognostic marker for patients with RV dysfunction.