Transthyretin Cardiac Amyloidosis in Australia and New Zealand-A Multi-Site Snapshot for 2022.

Objective: To estimate the burden of transthyretin cardiac amyloidosis (ATTR-CA) through a cross- sectional 'snapshot' of Australian Amyloidosis Network (AAN) and New Zealand (NZ) specialist amyloidosis clinics.

Design, setting & participants: A prospective survey was performed of seven AAN/ specialist amyloidosis clinics across Australia and NZ. All centres were invited to contribute data; participating centres provided clinical and demographic data for patients with ATTR-CA reviewed in the 2022 calendar year. Patients with new or previously confirmed ATTR-CA reviewed in the 2022 calendar year were included. Diagnosis was established through a positive cardiac scintigraphy scan in the absence of a monoclonal gammopathy or through a cardiac biopsy staining positive with transthyretin (TTR).

Results: A total of 515 patients were reviewed across seven sites. A total of 302/515 (59%) were wild type TTR (ATTRwt), 63/515 (12%) were variant ATTR (ATTRv) and the remaining 150 (29%) had not undergone genetic testing at the time of data collection. A total of 455/515 (88%) patients were male. Compared to ATTRwt, patients with ATTRv had smaller left ventricular (LV) wall thickness (IVSd 14±3 mm vs 16±3mm, p<0.001), and better LV systolic function (LVGLS -15.4±5% vs -11.7±3%, p<0.001). Most patients, 387/515 (75%) were on at least one ATTR specific treatment, including EGCG (157), diflunisal (139), doxycycline (68) and tafamidis (78), acoramidis (33) and gene silencer therapies or monoclonal antibodies (23).

Conclusion: A significant number of patients with ATTR-CA are seen in specialist amyloidosis clinics across Australia and NZ. Most patients received specific amyloidosis therapy, thorough enrollment in clinical trials. With increased recognition of amyloidosis and newer therapies becoming available, the volume of patients seen in these clinics is likely to increase.