105 Impact of global left ventricular afterload and transaortic gradient on myocardial work in patients with aortic stenosis and preserved ejection fraction

Abstract

Abstract Funding Acknowledgements Dr. Ilardi is supported by a research grant from Cardiopath PhD program. Background Myocardial work (MW) is a new parameter that derives from myocardial strain and provides an incremental value to myocardial function, incorporating measurement of deformation and load. To date, little is known about the changes in MW related to AS severity and arterial compliance. Purpose We investigated the effect of severity of AS, valvulo-arterial impedance (Zva) and stroke volume in patients with AS and preserved LV ejection fraction (EF). Methods 283 patients (60% males, mean age 71 ± 12 years old) with varying grades of AS and LVEF≥50% were enrolled. Exclusion criteria were more than mild associated cardiac valve lesion, left bundle branch block, and suboptimal quality of speckle-tracking image analysis. The control group included 50 patients matched for age and sex. Clinical, demographic and resting echocardiographic data were recorded, including quantification of 2D global longitudinal strain (GLS), global work index (GWI), global constructive work (GCW), global wasted work (GWW) and global work efficiency (GWE). Results Patients with AS had higher systolic (p = 0.017) and diastolic arterial pressure (p = 0.007), increased LV wall thickness, mass index (p < 0.001) and volumes (p = 0.045) compared to controls. Greater indexed left atrial volume, E/e’ and trans-tricuspid gradient were also observed in the AS group (p < 0.001). As expected, speckle tracking analysis revealed significant lower GLS in AS than in control group (18.7 ± 3.2 vs 20.7 ± 2.1%, p < 0.001). Conversely, increased values of GCW and GWI (respectively 2965 ± 647 vs 2360 ± 353 mmHg%, and 2535 ± 559 vs 2005 ± 302 mmHg%, p < 0.001) were observed in patients with AS. Besides, GWW was significantly increased in AS vs controls (147 ± 108 vs 90 ± 49 mmHg%, p = 0.001), with no changes in terms of GWE (95 ± 4 vs 96 ± 2%, p = 0.110). When patients were stratified according to the AS severity, the analysis of variance revealed that GCW, GWI and GWW significantly increased with higher transaortic mean gradient and lower aortic valve area (p < 0.001). Also Zva demonstrated to impact on CGW (p = 0.040) and GWW (p < 0.001), with increased values in presence of increased global LV afterload (Zva > 4.5 mmHg/ml/m2). Conversely, patients with low-flow AS (stroke volume index < 35 ml/m2) showed lowers values of GCW (p = 0.014) and GWI (p = 0.001) compared to normal flow AS, but increased GWW (p = 0.041) and reduced GWE (93 ± 7 vs 95 ± 4%, p = 0.010). At multivariable analysis, mean gradient (p < 0.001), Zva (p = 0.038), systolic blood pressure (p < 0.001) and GLS (p < 0.001) were independently associated with GWI and GCW, while only GLS was associated with GWW. Conclusion In patients with AS and preserved LVEF, GLS reduction is accompanied by an increase of GCW, GWI and GWW, without affecting the GWE. These MW modifications seem to be mainly correlated to the severity of AS and increased global LV afterload.