Objectives: To define whether the high sensitivity cardiac troponin T (hs-cTnT) assay in patients with immunoglobulin light chain amyloidosis (AL) improves risk prediction.
Background: Cardiac involvement is the major cause of death in patients with AL amyloidosis. Risk stratification is facilitated by cardiac biomarkers such as cardiac troponin T (cTnT) and N-terminal pro B-type natriuretic peptide (NT-proBNP).
Methods: Stored serum from patients with newly diagnosed AL was used to measure hs-cTnT, cTnT, and NT-proBNP. Survival modelling was performed.
Results: The direct numeric result from hs-cTnT measurement cannot merely be substituted for a cTnT measurement in the Mayo AL staging system. The performance of the receiver operator curve derived an hs-cTnT cut-point of 54 ng/L which improves on the value of 35 ng/L validated with the prior iteration of the assay. An alternate staging option using hs-cTnT alone-using the two thresholds 14 ng/L and 54 ng/L-performs as well as either the original Mayo AL staging system or other systems incorporating hs-cTnT. On multivariate analysis, an hs-cTnT alone staging system was independent of period of diagnosis, type of therapy, and NT-proBNP value, the last of which dropped out of the model. Alternate models were explored, but none performed better than the original system or the new hs-cTnT system. Thus, hs-cTnT can be used alone for the staging of disease prognosis.
Conclusions: A survival model based on hs-cTnT improves the prognostic staging of patients with AL amyloidosis, relegating NT-proBNP to a measure of cardiac response.