Systemic light chain (AL) amyloidosis is an uncommon disease that results from organ deposition of light chain immunoglobulins produced by a plasma cell neoplasm. Cardiac involvement with the disease is the primary determinant of prognosis, and the cardiac biomarkers N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin have formed the backbone for prognostication in AL amyloidosis over the last decade. Accurate assessment of baseline risk and cardiac treatment response are critical to guide treatment selection and intensity of therapeutic monitoring.

In this issue of Heart, Cohen et al 1 evaluated the 6 min walk test (6MWT) as a prognostic indicator in patients with AL amyloidosis. Seven hundred and ninety-nine patients with newly diagnosed AL amyloidosis seen at the UK National Amyloidosis Centre were prospectively enrolled in an observational study and followed for a median of 32 months. The 6 min walk distance (6MWD) was assessed at baseline and at 6 months, 12 months, 18 months and 24 months following initiation of upfront bortezomib-based therapy; 51 patients also underwent autologous stem cell transplantation. Baseline 6MWD was worse in patients with cardiac involvement and correlated with Mayo disease stage, Eastern Cooperative Oncology Group (ECOG) performance status and New York Heart Association (NYHA) stage. At 6-month and 12-month follow-up, greater improvement in 6MWD was seen in patients with deeper haematological response as well as in patients with cardiac response to therapy by NT-proBNP criteria. Both baseline 6MWD and improvement in …