Abstract 13459: Usefulness of B-Type Natriuretic Peptide and High-Sensitivity Cardiac Troponin for Risk Stratification in Low Flow, Low Gradient Aortic Stenosis -A Substudy of the TOPAS Study

Abstract

Background: B-type natriuretic peptide (BNP) and troponin T (TNT) have been shown to be associated with outcome in several clinical conditions. However the prognostic value of these 2 biomarkers combined together remains unclear. We aimed to explore the prognostic value of combined BNP and high-sensitivity TNT (hsTNT) in patients with low flow low gradient aortic stenosis (LGLG AS). Methods: Ninety eight patients (74±10 year; 75% men) with LFLG AS (LVEF <50% and/or SVi<35 ml/m2, mean gradient<40 mmHg, AVAi<0.6 cm2/m2) were prospectively enrolled in the TOPAS study and included in this analysis. The cohort was divided into three groups according to BNP and hsTNT plasma levels: Group A, patients with BNP<550 pg/mL and undetectable TNT (hsTNT<0.015 ng/mL); Group B, with BNP≥550 pg/mL or hsTNT≥0.015 ng/mL and Group C, patients with BNP≥550 pg/mL and hsTNT≥0.015 ng/mL. The primary endpoint was all-cause mortality. Results: Among the 98 patients, 32 (33%) were in Group A, 39 (40%) in Group B and 24 (27%) in Group C. During a median follow up of 2.8 [IQR=1.1-4.1] years, 55 patients died. Patients in Group C were older and had lower LVEF (all p<0.05). Two-year mortality was higher in Group C (41±9%) than in Group B (23±7) and Group A (5±4%) (p=0.0019). In Group B, there was no significant difference in 2-year mortality rates between the subgroup with hsTNT≥0.015 ng/mL versus that with BNP≥550 pg/mL (26±9% vs. 11±10%, respectively, p=0.21). In multivariable analysis adjusted for age, type of treatment (AVR vs. conservative), coronary artery disease and LVEF, Group C remained independently associated with increased risk of mortality (HR= 4.25; p=0.023), and Group B tended to have higher mortality (HR=3.63; p=0.058) as compared to Group A. Conclusion: The results of this study demonstrate the usefulness of combined measures of BNP and hsTNT to enhance risk stratification in patients with LFLG AS. Patients having activation of both BNP and hsTNT have a 4-fold increase risk of mortality.