Pilot Study of F18-Florbetapir in the Early Evaluation of Cardiac Amyloidosis.

Brett W Sperry,Frank P Difilippo,Wael A Jaber,Joseph P Donnelly,Ashley Bock,Mazen Hanna

doi:10.3389/fcvm.2021.693194

Abstract

Background: Cardiac amyloidosis is an increasingly recognized etiology of heart failure, in part due to the rise of non-invasive nuclear bone scintigraphy. Molecular imaging using positron emission tomography (PET) has promised the direct visualization of cardiac amyloid fibrils. We sought to assess the performance of F18-florbetapir PET in patients with a potential for cardiac amyloidosis in order to identify early disease.Methods: We performed a pilot study of 12 patients: one with asymptomatic transthyretin cardiac amyloidosis, seven with a potential for developing cardiac amyloidosis (two smoldering myeloma and five with extracardiac biopsy demonstrating transthyretin amyloid deposits and negative technetium pyrophosphate scans), and four controls. Patients were imaged with PET/CT in listmode 10–20 min after receiving F18-florbetapir. Static images were created from this acquisition, and mean standardized uptake values (SUVs) of the left ventricular myocardium, blood pool, paraspinal muscles, and liver were calculated.Results: All 12 patients demonstrated radiotracer uptake in the myocardium with mean SUV of 2.3 ± 0.4 and blood pool SUV of 0.8 ± 0.1. The patient with cardiac amyloidosis had SUV of 3.3, while mean SUV for patients at risk was 2.3 ± 0.4 and for controls was 2.2 ± 0.3. After 3 years of follow-up, one patient with SUV below the mean was subsequently diagnosed with ATTR cardiac amyloidosis.Conclusion: In this cohort, PET with F18-florbetapir demonstrated non-specific radiotracer uptake in the myocardium in all patients using a static image protocol; though, the highest values were noted in a patient with ATTR cardiac amyloidosis. There was no difference in the intensity of F18-florbetapir uptake in at-risk patients and controls. Future studies should continue to investigate metabolic PET tracers and protocols in cardiac amyloidosis, including in early disease.

Highlights

Cardiac amyloidosis is an increasingly recognized etiology of heart failure [1], in part due to the rise of non-invasive cardiac imaging such as echocardiography with longitudinal strain, nuclear bone scintigraphy, and cardiac magnetic resonance imaging
One patient was considered to have ATTR cardiac amyloidosis, seven patients had a potential for development of cardiac amyloidosis, and there were four control patients
positron emission tomography (PET) images were reoriented along the standard cardiac axes and the mean and standard deviation of cardiac uptake in the entire myocardium was quantified using standardized uptake values (SUVs)

Summary

Introduction

Cardiac amyloidosis is an increasingly recognized etiology of heart failure [1], in part due to the rise of non-invasive cardiac imaging such as echocardiography with longitudinal strain, nuclear bone scintigraphy, and cardiac magnetic resonance imaging. Echocardiography with longitudinal strain and cardiac magnetic resonance imaging may demonstrate findings consistent with cardiac amyloidosis and improve prognostication, while bone scintigraphy with technetium-based agent [pyrophosphate (PYP), 3,3diphosphono-1,2-propanodicarboxylic acid (DPD), and hydroxymethylene diphosphonate (HMDP)] are highly specific for transthyretin cardiac amyloidosis in the setting of negative blood and urine testing for a plasma cell disorder [2]. These modalities have typically been studied in symptomatic patients, though there is evidence that pre-symptomatic/early disease may be detected [3]. We sought to assess the performance of F18-florbetapir PET in patients with a potential for cardiac amyloidosis in order to identify early disease

Methods

Results

Conclusion