ST2 in patients with severe aortic stenosis and heart failure

Abstract

Background: ST2 is a circulating biomarker that is well established for predicting outcome in heart failure (HF). This is the first study to look at ST2 concentrations in optimally treated patients with stable but significant left ventricular systolic dysfunction (LVSD) compared to patients with severe aortic stenosis (AS).

Methods: Two cohorts were retrospectively studied: 94 patients undergoing transcatheter aortic valve implantation for severe AS (63 with normal ejection fraction [EF] and 31 with reduced EF), and 50 patients with severe LVSD from non-valvular causes. ST2 pre-procedural samples were taken, and repeated again at 3 and 6 months. Patients were followed-up for 2 years. Data was analyzed using SPSS software.

Results: Baseline concentrations of soluble ST2 did not differ significantly between the HF group and AS group with normal EF (EF ≥ 50%). However, in the AS group with a low EF (EF < 50%) ST2 concentrations were significantly higher that the HF group (p = 0.009). New York Heart Association class IV HF, baseline N-terminal pro-B-type natriuretic peptide and gender were all independent predictors of soluble ST2 (sST2) baseline concentrations.

Conclusions: Raised ST2 concentrations in the context of severe AS may be a marker for subclinical or clinical left ventricular dysfunction. More research is required to assess its use for assessment of prognosis and response to treatment.

Keywords: ST2; aortic stenosis; biomarkers; heart failure; transcatheter aortic valve implantation.

Figure 1

Box plots of the cohort median ST2 concentrations using a left ventricular ejection fraction (LVEF) cut-off value of < 50%. The Kruskal-Wallis test indicated that the difference between the patients with heart failure (HF) and those with aortic stenosis (AS) and a low ejection fraction with respect to ST2 concentration was significant (*p = 0.009).

Figure 2

Box plots of the cohort baseline ST2 concentrations using a left ventricular systolic dysfunction (LVSD) cut-off value of < 40%. The Kruskal-Wallis test indicated that the difference between the patients with heart failure (HF) and those with aortic stenosis (AS) and LVSD with respect to the ST2 concentration was significant (p = 0.049); LVEF — left ventricular ejection fraction; *p = 0.049.

Figure 3

Kaplan-Meier plots for the cohorts split at the median ST2 concentration. The green line is the high ST2 concentration, and the blue line is the low ST2 concentration.

Figure 4

Kaplan-Meier plots of survival probability of the cohorts using a left ventricular systolic dysfunction (LVSD) cut-off value of left ventricular ejection fraction (LVEF) < 50%. The blue line represents the heart failure group, the green line represents the aortic stenosis (AS) group without LVSD, and the yellow line represents the AS group with LVSD. The scale of the x-axis is in days up to 3 years.

Figure 5

Kaplan-Meier plots of the survival probability of the patient population according to baseline N-terminal pro-B-type natriuretic peptide (NT-proBNP). This was split at the NT-proBNP median concentration, up to the time at which the data were censored, which was 3 years. The blue line represents patients with NT-proBNP concentration above median and the green line represent the patients with NT-proBNP concentration below median.