Myocardial work as an independent predictor of postoperative NT-proBNP after transcatether aortic valve replacement
Authors: Ladanyi Z , Ruppert M , Fabian A , Ujvari A , Turschl T , Fejer C , Apor A , Nagy A I , Molnar L , Kovacs A , Merkely B , Lakatos B K 
Published: June 2023

Abstract

Funding Acknowledgements
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): SUPPORTED BY THE ÚNKP-22-3-I NEW NATIONAL EXCELLENCE PROGRAM OF THE MINISTRY FOR CULTURE AND INNOVATION FROM THE SOURCE OF THE NATIONAL RESEARCH, DEVELOPMENT AND INNOVATION FUND.

Introduction
Aortic valve stenosis is one of the most prevalent valvular disease with significant clinical burden. Its treatment has been revolutionized by transcatether aortic valve replacement (TAVR). Left ventricular function is key element of preprocedural patient assessment, however, conventional echocardiographic parameters are substantially influenced by the increased afterload associated with the valvular disease. Myocardial work index is a novel echocardiographic parameter that quantifies myocardial deformation in the context of the concomitant left ventricular pressure, therefore, it may be a reliable measure of left ventricular contractility even with increased afterload.

Purpose
Our aim was to evaluate the left ventricular function of the TAVR patients using conventional echocardiographic parameters and myocardial work index, and examine their association with the clinical characteristics of the patients.

Methods
84 TAVR candidates were enrolled (age 79±6 years; 48% female). Conventional and advanced echocardiographic measurements were performed prior to the procedure and at 12 months as a part of a follow-up visit. We measured ejection fraction (EF), and also global longitudinal strain (GLS) by speckle-tracking echocardiography, then using left ventricular volume curves estimated from systolic blood pressure and mean transaortic gradient, we quantified global myocardial work index (GWI). Detailed medical history, symptomatic status and as a marker of congestion, NT-proBNP levels were also obtained.

Results
EF did not change significantly (53±13 vs. 55±10 %; p = 0.172), while the absolute value of GLS increased substantially (−13.5±4.5 vs. −15.3±3.6 %; p&lt;0.001). GWI significantly decreased (1914±787 vs. 1666±594 mmHg%; p = 0.001) compared to the preprocedural values (Figure 1). TAVR significantly reduced the NT-proBNP levels of the cohort (1057 [586–3037] vs. 627 pg/mL [376–1198]; p&lt;0.001). Using multivariate regression analysis, examining relevant preprocedural clinical and echocardiographic parameters, the presence of atrial fibrillation (β=0.31; p&lt;0.01), and the preprocedural GWI value (β=-0.32; p&lt;0.01) proved to be significant independent predictors of postprocedural NT-proBNP (R²=0.30; p&lt;0.001).

Conclusions
In our study population global longitudinal strain and myocardial work changed significantly after the procedure. The GWI value and the presence of atrial fibrillation proved to be independent predictors of NT-proBNP measured during the postprocedural follow-up. Accordingly, GWI may help in the improvement of patient selection and the estimation of the clinical prognosis in this complex population.