18F-Florbetapir Binds Specifically to Myocardial Light Chain and Transthyretin Amyloid Deposits. (August 2015)

• Record Type: Journal Article
• Authors: Park, Mi-Ae; Padera, Robert F.; Belanger, Anthony; Dubey, Shipra; Hwang, David H.; Veeranna, Vikas; Falk, Rodney H.; Di Carli, Marcelo F.; Dorbala, Sharmila
• Is Part Of: Circulation. Volume 8:Number 8(2015)
• Publication Date: 2015-08
• Subjects: Cardiovascular system -- Imaging -- Periodicals; Heart -- Imaging -- Periodicals; 616.1075405
• DOI: 10.1161/CIRCIMAGING.114.002954
• Languages: English
• ISSNs: 1941-9651

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <title>Background—</title> <p> <sup>18</sup>F-florbetapir is a promising imaging biomarker for cardiac light chain amyloidosis (AL) and transthyretin amyloidosis (ATTR). Our aim, using human autopsy myocardial specimens, was to test the hypothesis that <sup>18</sup>F-florbetapir binds specifically to myocardial AL and ATTR amyloid deposits.</p> </sec> <sec> <title>Methods and Results—</title> <p>We studied myocardial sections from 30 subjects with autopsy-documented AL (n=10), ATTR (n=10), and nonamyloid controls (n=10) using <sup>18</sup>F-florbetapir and cold florbetapir compound and digital autoradiography. Total and nonspecific binding of <sup>18</sup>F-florbetapir was determined using the maximum signal intensity values. Specific binding of <sup>18</sup>F-florbetapir was calculated by subtracting nonspecific from total binding measurements (in decays per minute/mm<sup>2</sup>, DPM mm<sup>2</sup>) and was compared with cardiac structure and function on echocardiography and the histological extent of amyloid deposits. Diffuse or focally increased <sup>18</sup>F-florbetapir uptake was noted in all AL and ATTR samples and in none of the control samples. Compared with control samples, mean <sup>18</sup>F-florbetapir–specific uptake was significantly higher in the amyloid samples (0.94±0.43 versus 2.00±0.58 DPM/mm<sup>2</sup>; <italic>P</italic><0.001), and in the AL compared with the ATTR samples (2.48±0.40 versus 1.52±0.22 DPM/mm<sup>2</sup>; <italic>P</italic><0.001). The samples from subjects with atypical echocardiographic features of amyloidosis showed quantitatively more intense <sup>18</sup>F-florbetapir–specific uptake compared with control samples (1.50±0.17 versus 0.94±0.43 DPM/mm<sup>2</sup>; <italic>P</italic>=0.004), despite smaller amyloid extent than in subjects with typical echocardiograms.</p> </sec> <sec> <title>Conclusions—</title> <p> <sup>18</sup>F-florbetapir specifically binds to myocardial AL and ATTR deposits in humans and offers the potential to screen for the 2 most common types of myocardial amyloid.</p> </sec> </abstract>