Non-invasive left ventricular myocardial work identifies subclinical myocardial involvement in patients with systemic lupus erythematosus

Abstract

Objective: Global myocardial work (MW) is a novel indicator that accounts for deformation and afterload, which may provide additional value for assessment of myocardial function. Non-invasive echocardiographic estimated left ventricular (LV) MW incorporates longitudinal strain curves and blood pressure data. This study sought to assess MW in systemic lupus erythematosus (SLE) patients with normal LV ejection fraction (LVEF) by two-dimensional speckle-tracking imaging (2D-STI) to reflect subclinical myocardial damage.

Methods: 98 SLE patients and 98 gender and age-matched healthy subjects were included. The patients with SLE were divided into mild activity (SLE disease activity index (SLEDAI) ≤ 4; n = 45), moderate activity (5 ≤ SLEDAI ≤ 9; n = 23), and high activity (SLEDAI ≥ 10; n = 30) subgroups. Standard transthoracic echocardiography was applied to evaluate the systolic myocardial function of the global LV. The parameters of non-invasive MW including global wasted work (GWW) and global work efficiency (GWE) were calculated from echocardiographic LV pressure-strain loops (PSL) and blood pressure at rest.

Results: The SLE group had a significantly higher GWW (75.7 ± 39.1 mmHg% vs 37.9 ± 18.0 mmHg%, P < 0.001) and decreased GWE ratio (95.5 ± 2.0% vs 97.4 ± 1.0%, P < 0.001) compared with the controls. Among the subgroups with elevating level of disease activity, SLE patients with preserved LVEF had a significantly higher GWW (61.6 ± 29.9 mmHg% to 96.2 ± 42.2 mmHg%, P for trend = 0.001) and markedly decreased GWE (96.4 ± 1.5% to 94.4 ± 2.0%, P for trend = 0.001). In two separate multiple linear regression analyses, SLEDAI were independently associated with GWW (β = 0.271, P = 0.005) and GWE (β = -0.354, P<0.001).

Conclusion: GWW and GWE are promising novel tools for the early detection of subclinical LV dysfunction. GWW and GWE could distinguish distinct patterns in different grades of SLEDAI.

Keywords: Echocardiography; Myocardial involvement; Myocardial work; Systemic lupus erythematosus; Systemic lupus erythematosus disease activity index.