Suppression of tumorigenicity 2 (st2) turbidimetric immunoassay and enzyme-linked immunosorbent assay: Predicting risk in heart failure
Aurora L, Snider J, Peterson E, Bryson T, Gui H, McCord J, and Lanfear DE. Suppression of tumorigenicity 2 (st2) turbidimetric immunoassay and enzyme-linked immunosorbent assay: Predicting risk in heart failure. Journal of the American College of Cardiology 2020; 75(11):883.
J Am Coll Cardiol
Background Heart failure (HF) is a major public health problem worldwide. Cardiac biomarkers aid in diagnosis, prognosis, risk stratification, and management of HF. Soluble suppression of tumorigenicity 2 (ST2) is a significant prognostic indicator in HF and seems to reflect response to treatment, particularly beta blockers. However, a limitation to its adoption is that it is an enzyme-linked immunosorbent assay (ELISA) which may be cumbersome and costly for laboratories. A turbidimetric immunoassay (TIA) that can run on a common chemistry analyzer could overcome this issue. We studied a novel TIA for ST2, comparing its performance to the validated ST2 (ELISA) in predicting survival in HF patients. Methods Patients age ≥18 years meeting Framingham definition for HF were enrolled in a prospective registry (Oct 2007-March 2015) at Henry Ford Hospital. Exclusion criteria included chronic supplemental oxygen or dialysis. Only patients with HF with reduced ejection fraction (<50%) and available plasma samples were included (n=727). ST2 measurements were obtained on the same sample using both TIA and ELISA. Correlation was studied between the measures and association with survival using Cox models. Area under the curve (AUC) improvement in Cox models was studied using method of Uno. Results Study cohort included 66.6% males, 46.2% African Americans with 43 deaths over 1 year. Correlation between TIA and ELISA was initially low with spearman coefficient 0.63. There were four outliers with ELISA value greater than the recommended maximum (200 ng/mL). Exclusion of these samples (n=723) resulted in inter-assay correlation 0.87. In this group with only ST2 as a variable, the TIA and ELISA values were significant associates of survival time with similar effect size (HR 4.8 and 3.7, respectively, p=0.001). In models adjusted for clinical risk factors (MAGGIC score), both versions of ST2 remained a significant predictor of survival and were of similar magnitude; the AUC improvement (from MAGGIC only, AUC=0.756) for TIA AUC=0.777 (p=0.035) and for ELISA AUC=0.785 (p=0.028). Conclusion Novel TIA method for ST2 quantification correlates highly with ELISA and offers similarly powerful risk-stratification.