Quantification of right ventricular amyloid burden with 18F-florbetapir positron emission tomography/computed tomography and its association with right ventricular dysfunction and outcomes in light-chain amyloidosis.

Aims: In systemic light-chain (AL) amyloidosis, quantification of right ventricular (RV) amyloid burden has been limited and the pathogenesis of RV dysfunction is poorly understood. Using 18F-florbetapir positron emission tomography/computed tomography (PET/CT), we aimed to quantify RV amyloid; correlate RV amyloid with RV structure and function; determine the independent contributions of RV, left ventricular (LV), and lung amyloid to RV function; and associate RV amyloid with major adverse cardiac events (MACE: death, heart failure hospitalization, cardiac transplantation).
Methods and Results: We prospectively enrolled 106 participants with AL amyloidosis (median age 62 years, 55% males) who underwent 18F-florbetapir PET/CT, magnetic resonance imaging, and echocardiography. 18F-florbetapir PET/CT identified RV amyloid in 63% of those with and 40% of those without cardiac involvement by conventional criteria. RV amyloid burden correlated with RV ejection fraction (EF), RV free wall longitudinal strain (FWLS), RV wall thickness, RV mass index, N-terminal pro-brain natriuretic peptide, troponin T, LV amyloid, and lung amyloid (each P < 0.001). In multivariable analysis, RV amyloid burden, but not LV or lung amyloid burden, predicted RV dysfunction (EF P = 0.014; FWLS P < 0.001). During a median follow-up of 28 months, RV amyloid burden predicted MACE (P < 0.001).
Conclusion: This study shows for the first time that 18F-florbetapir PET/CT identifies early RV amyloid in systemic AL amyloidosis prior to alterations in RV structure and function. Increasing RV amyloid on 18F-florbetapir PET/CT is associated with worse RV structure and function, predicts RV dysfunction, and predicts MACE. These results imply a central role for RV amyloid in the pathogenesis of RV dysfunction.
Competing Interests: Conflict of interest: O.F.C.: Research fellowship from the International Society of Amyloidosis and Pfizer. S.A.M.C.: Investigator-initiated research grant from Pfizer. A.J.Y.: Consulting fees from AbbVie, Adaptive Biotechnologies, Amgen, Bristol-Myers Squibb, Celgene, GlaxoSmithKline, Janssen, Karyopharm, Oncopeptides, Regeneron, Sanofi, and Takeda. V.S.: Research support from Takeda, Celgene, Janssen, and Prothena and scientific advisory board for Caelum Biosciences. F.L.R.: Consulting fees from AstraZeneca and research support from Pfizer, Alnylam, and Ionis/Akcea. H.L.: Consulting fees from Celgene, Takeda, Janssen, Prothena, Pfizer, and Juno and research support from Amgen, Spectrum, and Takeda. R.Y.K.: Grant funding from Alnylam Pharmaceuticals. M.F.D.C.: Research grant from Spectrum Dynamics and Gilead and consulting fees from Sanofi and General Electric. R.H.F.: Consulting fees from Ionis Pharmaceuticals, Alnylam Pharmaceuticals, and Caelum Biosciences and research funding from GlaxoSmithKline and Akcea. S.D.: Consulting fees from Pfizer and GE HealthCare and investigator-initiated grant from Pfizer, Attralus, GE HealthCare, Phillips, and Siemens. The other authors do not have any conflicts of interest related to this study to declare.
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