Quantitative comparison between amyloid deposition detected by 99mTc-diphosphonate imaging and myocardial deformation evaluated by strain echocardiography in transthyretin related cardiac amyloidosis

Aims

The aim of our study is to assess the effect of amyloid deposition on myocardial function.

Methods and results

28 patients with transthyretin mutation and a group of 14 controls underwent echocardiography to quantify left ventricular (LV) dimensions and function, and global (G) longitudinal (L), radial (R) and circumferential (C) strain (S). 99mTc-3, 3-diphosphono-1, 2-propanodicarboxylic-acid-scintigraphy (99mTc-DPD) was used to quantify cardiac amyloidosis (CA). 99mTc-DPD revealed accumulation in 14 of 28 patients (CA-group) and no accumulation (no CA-group) in 14 patients. Cardiac accumulation was mild-moderate in 5 (Mild-Moderate CA-group) and severe in 9 patients (Severe CA-group). Severe CA-group showed higher values of LV septal thickness (LVST), posterior wall thickness and E/E’ ratio than the no CA-group and the control group (adj. p<0.05). Ejection fraction was similar among groups (p=0.65). GLS was lower (p=<0.001) in severe CA-group (-12.2 ± 4.5) respect to no CA-group (-19.3 ± 3.0) and to the control group (-20.9 ± 2.5). On the contrary, GCS and GRS were lower (p=<0.05) in mild-moderate CA-group (-10.8 ± 4.1 and 9.5 ± 5.7, respectively) respect to the severe CA-group (-18.9 ± 5.1 and 23.9 ± 6.3 respectively), no CA-group (-19.2 ± 4.1 and 28.4 ± 10.2 respectively) and the control group (-23.9 ± 4.4 and 29.9 ± 8.7 respectively). A correlation was found between the scintigraphic heart retention (HR) index and LVST (ρ=0.72; p<0.001) and E/E’ (ρ=0.46; p=0.03). An inverse tendency was observed between HR and GLS (ρ=−0.40; p=0.06).

Conclusions

99mTc-DPD HR is well correlated with LVST, diastolic and longitudinal systolic dysfunction.