T1 mapping and survival in systemic light-chain amyloidosis.
Banypersad SM., Fontana M., Maestrini V., Sado DM., Captur G., Petrie A., Piechnik SK., Whelan CJ., Herrey AS., Gillmore JD., Lachmann HJ., Wechalekar AD., Hawkins PN., Moon JC.
AIMS: To assess the prognostic value of myocardial pre-contrast T1 and extracellular volume (ECV) in systemic amyloid light-chain (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 (ECVb). 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 ECVb performed similarly. Isolated post-contrast T1 was non-predictive. In Cox 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.