Aims: The purpose of the study was to describe the pattern of 99mTc-labeled phosphate agents myocardial uptake by scintigraphy and explore its impact on left ventricular (LV) functions in transthyretin cardiac amyloidosis (TTR-CA).
Methods: Fifty patients with TTR-CA underwent 99mTc- hydroxymethylene-diphosphonate (99mTc-HMDP) scintigraphy and echocardiography with measure of LV thickness, longitudinal strain (LS), systolic and diastolic functions. Cardiac retention by scintigraphy was assessed by visual scoring and the heart/whole body (H/WB) ratio was calculated by dividing counts in the heart by counts in late whole-body images.
Results: The mean population age was 79 ± 10 years. Mean H/WB ratio was 12 ± 7. Myocardial 99mTc-HMDP uptake on segments 5, 6, 7, 8, 11, 12, 13, 14, 16, and 17 was correlated with H/WB ratio. Mean LVEF and global LS were 51 ± 10% and - 10 ± 3%, respectively. H/WB ratio was correlated with global LS (R = 0.408, P = .003), Ea (R = - 0.566, P < .001) and mean left ventricular wall thickness (R = 0.476, P < .001) but not with LVEF (R = - 0.109, P = .453). Segmental myocardial uptake was slightly correlated with segmental LS (R = 0.152, P < .001). H/WB ratio was not correlated with NT-proBNP levels (R = 0.219, P = .148) neither E/Ea ratio (R = 0.204, P = .184).
Conclusion: These findings show the relationship between bone tracer myocardial uptake and LV functions in patients with TTR cardiac amyloidosis.
Keywords: Amyloid heart disease; diseases/processes, SPECT; modalities, image analysis; technical, others; tracers.