Author + information
- Received March 12, 2018
- Revision received May 15, 2018
- Accepted June 26, 2018
- Published online August 15, 2018.
- Paco E. Bravo, MDa,e,
- Kana Fujikura, MD, PhDa,
- Marie Foley Kijewski, PhDb,
- Michael Jerosch-Herold, PhDa,
- Sophia Jacob, BSb,
- Mohamed Samir El-Sady, BSb,
- William Sticka, CNMTb,
- Shipra Dubey, PhDb,
- Anthony Belanger, PhDb,
- Mi-Ae Park, PhDb,
- Marcelo F. Di Carli, MDa,b,c,
- Raymond Y. Kwong, MD, MPHa,c,
- Rodney H. Falk, MDc,d and
- Sharmila Dorbala, MD, MPHa,b,c,d,∗ ()
- aNoninvasive Cardiovascular Imaging Program, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
- bDivision of Nuclear Medicine, Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
- cCardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
- dAmyloidosis Program, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
- eDivisions of Nuclear Medicine and Cardiology, Departments of Radiology and Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
- ↵∗Address for correspondence:
Dr. Sharmila Dorbala, Cardiac Amyloidosis Program, Cardiovascular Division, Department of Medicine, Heart & Vascular Center, Division of Nuclear Medicine, Department of Radiology, Brigham and Women’s Hospital and Harvard Medical School, 70 Francis Street, Shapiro 5th Floor, Room 128, Boston, Massachusetts 02115.
Objectives This study sought to test whether relative apical sparing (RELAPS) of left ventricular (LV) longitudinal strain (LS) in cardiac amyloidosis (CA) is explained by regional differences in markers of amyloid burden (18F-florbetapir uptake by positron emission tomography [PET] and/or extracellular volume fraction [ECV] by cardiac magnetic resonance (CMR)].
Background Further knowledge of the pathophysiological basis for RELAPS can help understand the adverse outcomes associated with apical LS impairment.
Methods This was a prospective study of 32 subjects (age 62 ± 7 years; 50% males) with light chain CA. All subjects underwent two-dimensional echocardiography for LS estimation and 18F-florbetapir PET for quantification of LV florbetapir retention index (RI). A subset also underwent CMR (n = 22) for ECV quantification. Extracellular LV mass (LV mass*ECV) and total florbetapir binding (extracellular LV mass*florbetapir RI) were also calculated. All parameters were measured globally and regionally (base, mid, and apex).
Results There was a significant base-to-apex gradient in LS (−7.4 ± 3.2% vs. −8.6 ± 4.0% vs. −20.8 ± 6.6%; p < 0.0001), maximal LV wall thickness (15.7 ± 1.9 cm vs. 15.4 ± 2.9 cm vs. 10.1 ± 2.4 cm; p < 0.0001), and LV mass (74.8 ± 21.2 g vs. 60.8 ± 17.3 g vs. 23.4 ± 6.2 g; p < 0.0001). In contrast, florbetapir RI (0.089 ± 0.03 μmol/min/g vs. 0.097 ± 0.03 μmol/min/g vs. 0.085 ± 0.03 μmol/min/g; p = 0.45) and ECV (0.53 ± 0.08 vs. 0.49 ± 0.08 vs. 0.49 ± 0.07; p = 0.15) showed no significant base-to-apex gradient in the tissue concentration or proportion of amyloid infiltration, whereas markers of total amyloid load, such as total florbetapir binding (3.4 ± 1.7 μmol/min vs. 2.8 ± 1.5 μmol/min vs. 0.93 ± 0.49 μmol/min; p < 0.0001) and extracellular LV mass (40.0 ± 15.6 g vs. 30.2 ± 10.9 g vs. 11.6 ± 3.9 g; p < 0.0001), did show a marked base-to-apex gradient.
Conclusion Segmental differences in the distribution of the total amyloid mass, rather than the proportion of amyloid deposits, appear to explain the marked regional differences in LS in CA. Although these 2 matrices are clearly related concepts, they should not be used interchangeably.
Drs. Bravo and Fujikura were supported by the National Institutes of Health T32 training grant (1T32HL094301). Drs. Dorbala, Falk, Kijewski, Di Carli, Jerosch-Herold, and Kwong are supported by National Institutes of Health RO1 grant (RO1 HL 130563); Dr. Dorbala is supported by an American Heart Association grant (AHA 16 CSA 2888 0004). Dr. Di Carli has received consulting fees from Sanofi and General Electric. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received March 12, 2018.
- Revision received May 15, 2018.
- Accepted June 26, 2018.
- 2018 American College of Cardiology Foundation
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