P2725Transthyretin cardiac amyloidosis in heart failure with preserved ejection fraction: Imaging by Tc-99m bone scan

Abstract Background Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous clinical syndrome with multiple underlying causes. Transthyretin amyloidosis (ATTR) is an underdiagnosed cause of HFpEF. Extraosseous uptake, in particular, myocardial uptake, was observed in a number of ATTR patients examined with the bone scan tracers. Objectives We sought to determine the prevalence of ATTR as detected by the bone scan among the patients admitted due to HFpEF. Methods We screened all consecutive patients ≥60 years old admitted due to HFpEF (left ventricular ejection fraction ≥50%). All eligible patients were offered an echocardiogram and a bone scan (a 99mTc-DPD/MDP/HMDP scintigraphy). Echocardiographic and clinical variables were gathered in all the subjects. The intensity of the myocardial uptake was graded according to a visual scale ranging from 0 to 3 points, in which the absence of uptake was assigned a score of 0 points; uptake less than that of bone (referred to as the adjacent rib), 1 point; uptake similar to that of bone, 2 points; and uptake greater than that of bone, 3 points. The distribution of the uptake in myocardium was defined as focal uptake, diffuse uptake, uptake in a ventricular wall segment, diffuse ventricular uptake, or diffuse biventricular uptake. Results The study included 62 HFpEF patients (52% women, 73±9 years). The bone scintigraphic analysis revealed relatively intense myocardial uptake in 7 of 62 patients (11.2%). 7 patients had intense Tc-99m uptake (score of 2–3) in the cardiac region, showing deposition in both right and left ventricles in every case. Patients with amyloid deposition were older (78±6 vs. 70±12 years, p<0.05), had a lower systolic blood pressure (118±23 vs. 148±28 mmHg, p<0.05), and left ventricular ejection fraction (52±11 vs. 58±6%, p<0.05). Both groups had at least moderate left ventricular hypertrophy and abnormal global longitudinal strain with no significant difference between groups. In 6 all the cases, the final diagnosis of amyloidosis was based on the results of abdominal fat aspiration biopsy. Conclusion ATTR is an underdiagnosed disease that accounts for a significant number (11.2%) of HFpEF cases. These findings create an opportunity for further investigation in the targeted therapy of patients with HFpEF.