Clinical Characteristics and Outcome of Patients with Wild-Type Transthyretin and AL Cardiac Amyloidosis Confirmed By Mass Spectrometry

INTRODUCTION: Cardiac involvement is common in both wild-type transthyretin (wATTR) and AL amyloidosis and these entities can have overlapping clinical features (Banypersad et al , JAHA 2012). Accurate diagnosis is vital given differences in spectrum of disease, management, and prognosis. We examined the presenting clinical features and survival outcome of patients diagnosed with cardiac wATTR and AL amyloidosis confirmed by mass spectrometry. MATERIALS & METHODS: Patients diagnosed between January 2014 and September 2017 with biopsy proven wATTR or AL amyloidosis and cardiac involvement by consensus criteria (Gertz et al , Amyloid 2010) were included. Mass spectrometry testing was performed at the Mayo Clinic Laboratories to confirm amyloid subtype in all cases. Patient records were retrospectively reviewed to identify clinical characteristics as well as details regarding treatment and survival. RESULTS: Forty-three patients were identified (wATTR n=27, AL n=16) with site of biopsy: 41 cardiac (95%); 1 gastric (2%); 1 skin (2%). Two (13%) patients with AL amyloid had coexisting multiple myeloma. Thirty-five (81%) patients were male, with a strong male predominance in wATTR patients (100% vs 50% for AL patients, p= Treatment for patients with AL amyloid was: bortezomib, cyclophosphamide, and dexamethasone (VCD) in 11 (69%); VCD followed by melphalan 200 mg/m2 autologous transplantation in 1 (6%); melphalan/dexamethasone in 1 (6%); no treatment in 2 (13%); unknown in 1 (6%). In evaluable patients, hematologic response rate was 54% (complete response n=4, very good partial response n=2, partial response n=1, no response n=6). With a median follow-up of 1.8 years for surviving patients, 1 year overall survival (OS) was 76% for the entire cohort. Patients with AL amyloidosis had significantly poorer 1 year OS (41% vs 92% for wATTR patients, p= et al , JCO 2012) of III-IV predicted for poor 1 year OS (19% vs 75% for stages I-II, p=0.03), as did not achieving complete response to primary treatment (1 year OS 33% vs 67% for CR patients, p=0.06). DISCUSSION & CONCLUSIONS: Male sex, older age, and lower LVEF were more common in patients with wATTR compared to AL amyloidosis. Higher levels of BNP, larger dFLC with lambda predilection, and higher bone marrow plasma cell percentage were more common in AL amyloid patients. Overall survival was significantly worse for patients with AL amyloidosis, particularly those with high NHYA class, advanced revised Mayo stage, and suboptimal response to primary therapy. These results highlight the importance of accurate amyloid sub-typing in patients with suspected cardiac amyloidosis. Disclosures No relevant conflicts of interest to declare.