RESUMEN
BACKGROUND: In systemic light-chain (AL) amyloidosis, cardiac involvement portends poor outcomes. OBJECTIVES: The authors' objectives were to detect early myocardial alterations, to analyze longitudinal changes with therapy, and to predict major adverse cardiac events (MACE) in participants with AL amyloidosis using cardiac magnetic resonance imaging (MRI). METHODS: Recently diagnosed participants were prospectively enrolled. AL amyloidosis with and without cardiomyopathy (AL-CMP, AL-non-CMP) were defined based on abnormal cardiac biomarkers and wall thickness. MRI was performed at baseline, 6 months in all participants, and 12 months in participants with AL-CMP. MACE were defined as all-cause death, heart failure hospitalization, and cardiac transplantation. Mayo stage was based on troponin T, N-terminal pro-B-type natriuretic peptide, and difference in free light chains. RESULTS: This study included 80 participants (median age 62 years, 58% men). Extracellular volume (ECV) was abnormal (>32%) in all participants with AL-CMP and in 47% of those with AL-non-CMP. ECV tended to increase at 6 months (median +2%; AL-CMP P = 0.120; AL-non-CMP P = 0.018) and returned to baseline values at 12 months in participants with AL-CMP. Global longitudinal strain (GLS) improved at 6 months (median -0.6%; P = 0.048) and 12 months (median -1.2%; P < 0.001) in participants with AL-CMP. ECV and GLS were strongly associated with MACE (P < 0.001) and improved the prognostic value when added to Mayo stage (P ≤ 0.002). No participant with ECV ≤32% had MACE, while 74% of those with ECV >48% had MACE. CONCLUSIONS: In patients with systemic AL amyloidosis, ECV detects subclinical myocardial alterations. With therapy, ECV tends to increase at 6 months and returns to values unchanged from baseline at 12 months, whereas GLS improves at 6 and 12 months in participants with AL-CMP. ECV and GLS offer additional prognostic performance over Mayo stage. (Molecular Imaging of Primary Amyloid Cardiomyopathy [MICA]; NCT02641145).
RESUMEN
Aims: In systemic light-chain (AL) amyloidosis, cardiac involvement portends poor prognosis. Using myocardial characteristics on magnetic resonance imaging (MRI), this study aimed to detect early myocardial alterations, to analyze temporal changes with plasma cell therapy, and to predict risk of major adverse cardiac events (MACE) in AL amyloidosis. Methods and Results: Participants with recently diagnosed AL amyloidosis were prospectively enrolled. Presence of AL cardiomyopathy (AL-CMP vs. AL-non-CMP) was determined by abnormal cardiac biomarkers. MRI was performed at baseline and 6 months, with 12-month imaging in AL-CMP cohort. MACE was defined as all-cause death, heart failure hospitalization, or cardiac transplantation. Mayo AL stage was based on troponin T, NT-proBNP, and difference in free light chains. The study cohort included 80 participants (median age 62 years, 58% males). Median left ventricular extracellular volume (ECV) was significantly higher in AL-CMP (53% vs. 30%, p<0.001). ECV was abnormal (>32%) in all AL-CMP and in 47% of AL-non-CMP. ECV tended to increase at 6 months and decreased significantly from 6 to 12 months in AL-CMP (median -3%, p=0.011). ECV was strongly associated with MACE (p<0.001), and improved MACE prediction when added to Mayo AL stage (p=0.002). ECV≤32% identified a cohort without MACE, while ECV>48% identified a cohort with 74% MACE. Conclusions: In AL amyloidosis, ECV detects subclinical cardiomyopathy. ECV tends to increase from baseline to 6 months and decreases significantly from 6 and 12 months of plasma cell therapy in AL-CMP. ECV provides excellent risk stratification and offers additional prognostic performance over Mayo AL stage.
