NPPB and AL amyloidosis: Indeed, the most widely accepted prognostic stratifications in AL amyloidosis (the original staging system reported by the Mayo group as well as its subsequent modifications) are based on the extent of cardiac involvement determined by the serum cardiac biomarkers N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiac troponin T; patients with a very high NT-proBNP and high cardiac troponin-T (Mayo stage 3b) have a median survival of 5 months.4–6