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

BACKGROUND Management of cardiac amyloidosis (CA) is related to amyloid deposition. Our aim was to assess the effect of amyloid deposition on myocardial function. METHODSANDRESULTS Twenty-eight patients with transthyretin mutation and a group of 14 controls underwent echocardiography to quantify left ventricular (LV) dimensions, function, and global (G) longitudinal (L), radial (R) and circumferential (C) strain (S). (99m)Tc-3,3-diphosphono-1,2-propanodicarboxylic-acid-scintigraphy ((99m)Tc-DPD) was used to quantify CA. (99m)Tc-DPD revealed accumulation in 14/28 patients (CA group) and no accumulation (no-CA group) in 14. Cardiac accumulation was lower-than-bone uptake in 5 (mild-CA group) and higher-than-bone uptake in 9 (severe-CA group). Ejection fraction was similar among groups. GLS was lower (P<0.001) in the severe-CA group (-12.2±4.5) with respect to the no-CA group (-19.3±3.0) and to the control group (-20.9±2.5). Conversely, GCS and GRS were lower (P<0.05) in the mild-CA group (-10.8±4.1 and 9.5±5.7, respectively) with 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 index (HRI) and LV septal thickness (ρ=0.72), E/E' (ρ=0.46) and GLS (ρ=-0.40). CONCLUSIONS Myocardial deformation is impaired in a different stage of CA. The (99m)Tc-DPD HRI correlated well with morphologic, diastolic and strain abnormalities. (Circ J 2016; 80: 1998-2003).