Patient Characteristics and Diagnosis of Transthyretin Amyloid Cardiomyopathy in Japan

BACKGROUND: Large-scale, nationwide data for patients with transthyretin amyloid cardiomyopathy (ATTR-CM) in Japan are limited. OBJECTIVES: This multicenter observational, retrospective cohort study (UMIN000056734) assessed the clinical characteristics and diagnostic landscape of patients with ATTR-CM in Japan. METHODS: A subcohort of patients with biopsy-proven ATTR-CM initiated on tafamidis from the J-COSSA (Japan Cohort Study of Systemic Amyloidosis) was evaluated (120 sites; April 2020 to January 2024). Baseline characteristics and investigations for the diagnosis of ATTR-CM were recorded. RESULTS: Tc)-labeled scintigraphy was performed in 796 (80.1%) of 994 patients, of whom single-photon emission computed tomography was performed in 652 (81.9%) patients (Perugini grade 3, 657 [82.5%]). Among the 993 patients with evaluable records, 521 (52.5%) had ≥5 symptoms among the 7 red-flag symptoms. CONCLUSIONS: This nationwide study clarified the clinical characteristics and diagnostic landscape of patients with biopsy-proven ATTR-CM in Japan. The results indicate that noninvasive testing is implemented for early ATTR-CM diagnosis in clinical practice and reiterate the importance of biomarkers and imaging data for early disease diagnosis.