Prognostic value of left ventricular myocardial work indices in patients undergoing transcatheter aortic valve replacement

Abstract

Abstract Introduction Left ventricular myocardial work (LVMW) is a novel echocardiographic-based method to assess LV function using pressure-strain loops taking LV afterload into account. In patients with aortic stenosis (AS), this approach was shown to improve assessment of LV performance as compared to conventional and advanced parameters of LV systolic function, but data on its prognostic value are lacking. Purpose To evaluate the prognostic value of LVMW indices in patients with severe AS undergoing transcatheter aortic valve replacement (TAVR). Methods LVMW indices, including LV global work index (GWI), global constructive work (GCW), global wasted work (GWW) and global work efficiency (GWE) were calculated in 281 patients with severe AS (age 82, IQR 78–85 years, 52% male) prior to the TAVR procedure. As previously validated, LV systolic pressure was derived non-invasively by adding the mean aortic gradient to the brachial systolic pressure. LV global longitudinal strain and LV systolic pressure were then incorporated to construct pressure-strain loops to determine the LVMW indices. The study endpoint was all-cause mortality. Results In the total population average GWI was 1872±753 mmHg%, GCW 2240±797 mmHg%, GWW 200 (IQR 127–306) mmHg% and GWE 89 (IQR 84–93)%. During a median follow-up of 52 (IQR 41–67) months, 64 patients died. These patients showed lower values of GWI (1644 vs 1940 mmHg%, p=0.006) and GCW (2010 vs 2307 mmHg%, p=0.009) as compared to patients who survived while GWW (197 vs 200 mmHg%, p=0.794) and GWE (88% vs 90%, p=0.102) were similar. While LV GCW, GWW and GWE did not show a significant association with the study endpoint, GWI was independently associated with all-cause mortality (HR per-tertile-increase 0.639; 95% CI 0.463–0.883; P=0.007), and the patients in the lowest GWI tertile showed the worst survival rates (Figure 1). Of interest, patients in the lowest GWI tertile were more likely to be male (63% vs 56% and 37% from the lowest to the highest tertile, P=0.001), had a higher prevalence of atrial fibrillation (26% vs 19% and 8% from the lowest to the highest tertile, P=0.006), worse renal function (53 mL/min/1.73 m2 vs 64 mL/min/1.73 m2 and 62 mL/min/1.73 m2 from the lowest to the highest tertile, P=0.038) and larger LV dimension (LVEDD 52 mm vs 47 mm and 46 mm from lowest through highest tertile, p<0.001). Importantly, when added to a basal model, LVGWI yielded a higher increase in predictivity compared to both conventional and advanced parameters of LV systolic function (Figure 2). Also, in a model corrected for the hemodynamic class of AS (high-gradient, low-flow low-gradient), GWI also showed a significant independent association (P=0.003) with all-cause mortality. Conclusions LVGWI is independently associated with all-cause mortality in patients undergoing TAVR and has a higher prognostic value compared to both conventional and advanced parameters of LV systolic function. Funding Acknowledgement Type of funding sources: None.