T1 mapping and survival in systemic light-chain amyloidosis.

Aims To assess the prognostic value of myocardial pre-contrast T1 and extracellular volume (ECV) in systemic amyloid lightchain (AL) amyloidosis using cardiovascular magnetic resonance (CMR) T1 mapping. Methods and results One hundred patients underwent CMR and T1 mapping pre- and post-contrast. Myocardial ECV was calculated at contrast equilibrium (ECV_i) and 15 min post-bolus (ECV_b). Fifty-four healthy volunteers served as controls. Patients were followed up for a median duration of 23 months and survival analyses were performed. Mean ECV_i was raised in amyloid (0.44±0.12) as was ECV_b (mean 0.44±0.12) compared with healthy volunteers (0.25±0.02), P , 0.001. Native pre-contrast T1 was raised in amyloid (mean 1080±87 ms vs. 954 ±34 ms, P , 0.001). All three correlated with pre-test probability of cardiac involvement, cardiac biomarkers, and systolic and diastolic dysfunction. During follow-up, 25 deaths occurred. An ECV_i of .0.45 carried a hazard ratio (HR) for death of 3.84 [95% confidence interval (CI): 1.53–9.61], P= 0.004 and pre-contrast T1 of .1044 ms= HR 5.39 (95% CI: 1.24–23.4), P= 0.02. Extracellular volume after primed infusion and ECV_b performed similarly. Isolated post-contrast T1 was non-predictive. InCox regression models, ECV_i was independently predictive of mortality (HR= 4.41, 95% CI: 1.35–14.4) after adjusting for E:E′, ejection fraction, diastolic dysfunction grade, and NT-proBNP. Conclusion Myocardial ECV (bolus or infusion technique) and pre-contrast T1 are biomarkers for cardiac AL amyloid and they predict mortality in systemic amyloidosis. [ABSTRACT FROM AUTHOR]