Imaging Cardiac Amyloidosis: A Pilot Study Using F-18 Florbetapir Positron Emission Tomography

Overview

The primary aim of this pilot study is to determine whether amyloid deposits in the heart can be measured non-invasively by F-18 florbetapir (Trade Name: Amyvid) positron emission tomography (PET) in 30 individuals with documented cardiac amyloidosis. We will also enroll 15 individuals without cardiac amyloidosis to undergo the F-18 florbetapir imaging as a control group. The primary hypothesis of this study is that a specific amyloid binding radiotracer will bind to the myocardial amyloid deposits and help quantify cardiac amyloid burden. A secondary aim of this study is to determine reproducibility of F-18 florbetapir imaging of the myocardium.

F-18 florbetapir has been studied in multiple clinical trials to image beta-amyloid deposition in the brain of subjects with Alzheimers' disease. Florbetapir F-18 has been well tolerated in studies of more than 2000 human subjects. Biodistribution studies in humans revealed predominantly hepatobiliary excretion. The tracer clears rapidly from the blood pool in about 20 minutes. This radiotracer has been recently approved for clinical imaging of brain amyloid in subjects with suspected Alzheimers disease. The investigators propose to test this FDA approved radiotracer for an off label indication in a pilot study to evaluate its potential utility, if any, to image cardiac amyloidosis. Amyloid related heart disease is associated with LV wall thickening due to infiltration; however, this myocardial wall thickening is not definitively distinguishable from left ventricular myocyte hypertrophy from increased afterload to the heart from hypertension or aortic stenosis. Typically myocardial or other tissue biopsy with typical echo features of amyloidosis is required for confirmation of amyloidosis. This pilot study is designed to understand whether cardiac amyloid burden can be measured using a specific radiotracer targeted against amyloid protein (F-18 Florbetapir). At this point it is unknown of F-18 Florbetapir will bind to either AL or TTR amyloid protein or to both of them or to neither of them. The investigators would like to study 15 patients with AL and 15 patients with TTR amyloidosis to understand these differences if any. The investigators also seek to understand if the signal to noise ratio of the circulating amyloid protein in the blood pool (AL amyloid disease) allows for good differentiation of myocardial amyloid uptake. 15 individuals without cardiac amyloidosis will also be enrolled as controls for this study. The purpose of the proposed research study is to examine in detail, using quantitative PET, myocardial F-18 Florbetapir uptake in cardiac amyloidosis in order to better understand mechanisms of heart damage in this disease. A secondary aim of this study is to determine reproducibility of F-18 florbetapir imaging of the myocardium in a subset of patients with amyloidosis who return for a second F-18 florbetapir scan within 30 days.