Left ventricular assessment in patients with systemic light chain amyloidosis: a 3-dimensional speckle tracking transthoracic echocardiographic study
Résumé
Cardiac involvement in systemic light chain (AL) amyloidosis carries a poor prognosis mainly through involvement of the left ventricular (LV) myocardium. Despite its limitations, two-dimensional transthoracic echocardiography (2D-TTE) remains the main tool used for the assessment of LV systolic function in AL patients. We hypothesize that 3D-TTE coupled with speckle tracking imaging allows earlier detection of LV systolic dysfunction than 2D-TTE in AL amyloidosis. We prospectively studied 71 subjects including 58 patients with confirmed AL amyloidosis (mean age 66 ± 10 years, 60% male) and 21 healthy control (mean age 64 ± 7 years, 48% male) from 2011 to 2014 at the University Hospital of Limoges. The AL patients were divided into three groups according to Mayo Clinic (MC) staging and all subjects underwent 2D-TTE and 3D-TTE at the same setting. Using 2D-TTE, there was no significant difference in LV ejection fraction (EF) between the groups [LVEF = 63 ± 7% (control), 59 ± 6% (MC stage I), 60 ± 8% (MC stage II) and 57 ± 14% (MC stage III) (p = 0.24)]. In contrast, 3D-TTE demonstrated significantly worse LV systolic function in stage II and III patients using 3D-LVEF [MC II and III 45 ± 8% and 39 ± 12% vs. control 53 ± 8% (p < 0.0001)], global longitudinal strain (GLS) [MC II and III - 11 ± 4% and - 8 ± 3% vs. control - 15 ± 3% (p < 0.0001)] and global radial strain (GRS) [MC II and III 14 ± 9% and 10 ± 8% vs. control 25 ± 10% (p < 0.0001)]. Furthermore, MC III patients had significantly worse global circumferential strain and area tracking [- 17 ± 6% and - 25 ± 8% vs. - 24 ± 7% and - 36 ± 7% for control (p < 0.0001)]. Additionally, MC I had significantly better 3D GLS, GRS and global strain (- 15 ± 3%, 25 ± 10% and 28 ± 12%) than MC II (- 11 ± 4%, 14 ± 9% and 16 ± 10%) and MC III patients (- 8 ± 3%, 10 ± 8% and 12 ± 8%), respectively. Despite an apparently preserved LVEF by 2D-TTE, AL patients in MC stage II and III demonstrate evidence of LV systolic dysfunction by 3D imaging using LVEF and strain analysis. Worse LV involvement by AL amyloidosis was associated with more impaired 3D-TTE LV systolic parameters.