Myocardial work evaluation in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background myocardial work (MW) is a novel echocardiographic technique which assesses left ventricular (LV) performance through LV pressure-strain loops. MW corrects speckle tracking echocardiography (STE)-derived parameters for afterload using non-invasive systolic blood pressure (SBP) as a surrogate for LV systolic pressure. In patients with severe aortic stenosis (AS), the corrected MW (cMW) has been proposed, consisting in adding the mean aortic gradient in SBP. This method revealed to be feasible and reliable, demonstrating good correlation with invasively measured LV systolic pressure. Purpose to evaluate myocardial performance of patients with severe AS, before and after transcatheter aortic valve implantation (TAVI), by MW indices. Methods patients with severe AS undergoing TAVI were included. Transthoracic, standard echocardiography and STE were performed the day before the procedure and within 2 days after. MW was calculated by combining STE-derived indices with non-invasively estimated LV systolic pressure. Results 30 patients (79 ± 5 years old, 56% females) with severe AS (mean gradient 47 ± 14 mmHg, aortic valve area 0.6 ± 0.1 cm2), and eligible for TAVI were enrolled. Baseline global longitudinal strain was impaired (GLS -15 ± 4%), in presence of normal LV ejection fraction (LVEF 57 ± 10%). Corrected global work index and global constructive work were preserved at baseline and markedly decreased after TAVI (cGWI 2322 ± 791 vs 1710 ± 505 mmHg%, p = 0.001; cGCW 2774 ± 803 vs 2083 ± 536 mmHg%, p = 0.0007). Corrected global wasted work and global work efficiency were higher than reference values existing in literature, and no significant changes were observed after TAVI (cGWW 276 ± 174 vs 277 ± 165 mmHg%, p = 0.974; cGWE 89 ± 5 vs 87 ± 5%, p = 0.177). A significant inverse correlation was found between baseline cGWI and left atrial volume index (r=-0.5, p = 0.03). Conclusions patients with severe aortic stenosis and preserved LVEF show a good LV performance before and after TAVI, with a significant decrease in MW indices after TAVI, because of the reduced afterload due to AS treatment. The negative correlation between left atrial volume and cGWI may reflect the extent of myocardial damage in AS. However, further studies with larger sample size and appropriate follow-up are needed to evaluate the role of MW in prognosis and risk stratification of this subset of patients.