Longitudinal systolic strain, cardiac function improvement, and survival following treatment of light-chain (AL) cardiac amyloidosis

To determine whether echocardiographic longitudinal systolic strain (LS) parameters identify short-term improvement following chemotherapy for light-chain (AL) cardiac amyloidosis (CA). Among patients with CA, standard echocardiographic measures are commonly unchanged at 1 year following successful chemotherapy, despite observed reductions in cardiac biomarkers.

We retrospectively identified 61 patients with AL-CA treated with high-dose melphalan or bortezomib-based regimens. Patients were classified by hematologic response at 1 year into two groups: complete response (CR; n = 18, or 30%) or non-CR (non-CR; n = 43, or 70%), and followed for 20 months. Serum free light chains (FLC), B-type natriuretic peptide (BNP), troponin I (TnI), and echocardiography including LS, were acquired at baseline and 1 year. Seven patients died (11.5%), all in the non-CR group (P < 0.01). At 1 year, while reductions were observed in BNP (44% CR, 18% non-CR) and FLC (94% CR, 73% non-CR), both P < 0.05 from baseline, there were no differences in wall thickness, EF, or diastolic function in either group. LS improved only in the CR group with notable improvement in apical to basal strain ratio (P < 0.05). Strain improvement and BNP reduction were correlated (R = 0.6, P < 0.01). Baseline global LS < -10.2% was associated with survival and proved superior to BNP and TnI. The addition of global LS to biomarkers identified the patients at highest risk of mortality.

These data suggest that LS is a sensitive measure of pre-treatment cardiac functional impairment in AL-CA, can predict survival over and above that of cardiac biomarkers, and detect early cardiac functional improvement following chemotherapy.