Myocardial work assessment in low-flow low-gradient aortic stenosis
J Gopal, A Pawa, C Fang, J Kim, J Jenkins, S QamruddinAbstract
Background
Low-flow, low-gradient aortic stenosis (LFLG AS) is associated with approximately 30% mortality at 2 years following transcatheter aortic valve replacement (TAVR). Contractile reserve (CR), assessed by dobutamine stress echocardiography (DSE), does not reliably predict mortality or ejection fraction (EF) improvement. Global longitudinal strain (GLS) has been shown to independently predict mortality in this population.
Purpose
Given GLS is load-dependent; Myocardial work (MW) is a novel echocardiographic parameter that integrates myocardial deformation and afterload and may help differentiate whether reduced GLS reflects intrinsic myocardial dysfunction or increased afterload. We evaluated the utility of baseline and 1-month post-TAVR MW parameters in predicting 1-year mortality in this population.
Methods
Baseline and 1-month post-TAVR GLS, global myocardial work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were measured using automated function imaging software. MW parameters were derived from noninvasive left ventricular pressure–strain loops incorporating brachial systolic blood pressure and mean aortic valve gradient. A total of 43 patients (age 79 ± 7 years; 74% male; 81% coronary artery disease; EF 37% [27.5–45.0]; GLS −9.5% ± 3.5) who underwent DSE between 2017 and 2025 were included. Patients with >10% absolute improvement in EF at 1 month were classified as responders. Receiver operating characteristic (ROC) curve analysis was performed to determine optimal cutoffs for prediction of 1-year mortality.
Results
At 1 month, 30% of the cohort were responders. Responders had significantly lower baseline EF compared with non-responders (p<0.001) (Table 1). One- and two-year mortality was 16% and 30%, respectively. CR (present in 47%) as well as baseline and 1-month post-TAVR EF were not predictive of 1-year mortality (Figure 1). Baseline GLS (AUC 0.89, cut off >–7%, p=0.002), GWI (AUC 0.87, cutoff <1185 mmHg% p=0.001), and GWE (AUC 0.78, cutoff <75%, p=0.02) showed high sensitivity and specificity for predicting 1-year mortality (Figure 1). Early (1-month) post-TAVR GWE demonstrated strongest discrimination (AUC 0.81, cut off <77%, p=0.035), outperforming 1-month GLS (AUC 0.77, cutoff >-8% p=0.045) for 1-year mortality. Responders demonstrated an increase in GWI and GWE, whereas non-responders exhibited a decline in these parameters despite comparable reductions in afterload at 1 month (Table 1).
Conclusion
Patients with LFLG AS undergoing TAVR have high mid-term mortality. Conventional measures including CR and EF were not predictive of 1-year mortality. In contrast, baseline and 1-month GLS and MW parameters demonstrated strong predictive value for subsequent mortality, supporting their role in early risk stratification in this population. Larger studies are warranted to confirm their independent prognostic value.Table 1Figure 1