Global longitudinal strain and NT-proBNP as predictors for LV function recovery after TAVR
Authors: Moya A , Delrue L , Beles M , Heggermont W , Verstreken S , Goethals M , Dierckx R , Bartunek J , Vanderheyden M 
Published: October 2022

Abstract

Introduction
Abnormal GLS values as well as high plasma levels of NT-proBNP previous to TAVR are independent predictors for higher peri-procedural mortality. Moreover, in a subgroup of TAVR patients LV function does not recover following the procedure. Until today, it is still unclear how to predict impaired post-procedural LV function for optimal clinical patient's management.

Purpose
This study was set up to assess the predictive value of baseline GLS and NT-proBNP levels on LV function recovery (LVfr) in a cohort of patients with severe AS referred for TAVR.

Methods
A total of 25 patients (9 male, 84±5 yo, EF 50±11%) with severe AS (AVA 0.6±0.3 cm2, MPG 49±16 mmHg) referred for TAVR were included. Blood analysis and TTE were performed before intervention (baseline, bl) and at follow-up (fu). Myocardial work was analysed offline integrating the longitudinal strain and afterload pressure (SBP + AVPmean). LVfr was defined as GLS &lt;−19% at fu. The median values at bl of NT-proBNP (1781 ng/L) and GLS (−15%) were taken as cut-off to categorize patients in 4 groups: NT-proBNPhighGLShigh, NT-proBNPlowGLShigh, NT-proBNPhighGLSlow and NT-proBNPlowGLSlow. The ROC curve analysis for prediction of LVfr after TAVR were performed.

Results
LV function recovered in 13 patients (52%). Despite similar EF and global MWI after TAVR, the LV contraction became more efficient as evidenced by a significant improvement (bl vs fu, p&lt;0.05) in GLS (−14±4.5 vs −18±4.2%), MWW (400±510 vs 157±107 mmHg%) MWE (88±6 vs 92±6%) together with a reduction in afterload pressure (203±38 vs 156±22 mmHg, p&lt;0.05). In the NT-proBNPlow groups, GLS (−15±4 vs −20±3%, p&lt;0.05) and MCW (2166±874 vs 2978±634 mmHg%, p&lt;0.05) at fu were significantly better when compared to the NT-proBNPhigh groups. Likewise, the GLSlow groups showed higher EF (47±10 vs 54±6%, p&lt;0.05) and MCW (2181±832 vs 2961±715 mmHg%, p&lt;0.05) than the GLShigh groups at fu. Interestingly, the GLSlow groups had lower LVESV (57±38 vs 29±10 ml, p&lt;0.05) and LVEDV (113±49 vs 80±20 ml, p&lt;0.05) post-TAVR than the GLShigh groups which suggests a positive remodelling following afterload reduction. At the ROC curve analysis, combined GLS and NT-proBNP at bl were better predictors for LVfr than each parameter alone, AUC 0.86 (Fig. 1). Additionally, only 20% LVfr was seen in the NT-proBNPhighGLShigh group in contrast to 67–75% in the other groups.

Conclusion
Elevated afterload in severe AS leads to a physiological reduction of GLS. Although the decrease in afterload after TAVR beneficially affects GLS and may lead to LVfr, this was not observed in a subgroup of patients with high NT-proBNP levels in whom GLS remained impaired at follow-up. We speculate that myocardial tissue damage and fibrosis due to long lasting high pressure exposure may partly be responsible for this observation. The combination of pre-procedural NT-proBNP levels and GLS shows strong predictive potential for LVfr after TAVR and larger studies are warranted for further evaluation and cut-off values determination.

Funding Acknowledgement
Type of funding sources: Foundation. Main funding source(s): Cardiovascular Research Center Aalst (npo)