Combined use of tissue Doppler imaging and natriuretic peptides as prognostic marker in asymptomatic aortic stenosis

Abstract

Introduction: Tissue Doppler imaging (TDI) and N-terminal-pro-Brain Natriuretic Peptide (NT-proBNP) provides useful non-invasive information about left ventricle filling pressures and both have demonstrated to be a prognostic marker in some valve disease as aortic stenosis (AS).

Objectives: To assess the clinical value of combined TDI and NT-proBNP information in asymptomatic AS patients.

Material and methods: Prospective study of 350 initially asymptomatic moderate to severe AS patients with: Mean aortic valve area 0.8 (0.3) cm², mean gradient 45(13) mmHg, ejection fraction 61 (9) %. Mean age: 74.6 (4.3) years. In all patients were determined NT-proBNP in the serum and TDI parameters the lateral mitral annulus. We considered clinical event the admission in the hospital due to symptoms related to AS (angina, heart failure or syncope) as well as surgical treatment or mortality.

Results: After a mean follow-up of 29 (10) months, 165 (47%) patients suffered some clinical event. In order to predict clinical events, Bootstrap analysis determined the best cut-point value: E/E' ratio higher than 13 and NT-proBNP higher than 515pg/mL. E/E' ratio provides more specificity (78.9% vs 55.9%) and NT-proBNP provides more sensitivity (76.6% vs 43.7%). Combined use of both parameters provides the best prognostic information (sensitivity 75.6%, specificity 67.2%, negative predictive value 82.1%, positive predictive value 57.5%, accuracy 71.4%).

Conclusion: Combined use of TDI and natriuretic peptides information provides incremental prognostic value and is a useful tool to predict the prognosis in asymptomatic AS patients.

Keywords: Aortic stenosis; Natriuretic peptides; Tissue Doppler imaging.