Abstract 10063: Changes in Clinical Phenotype of Patients With ATTR Cardiac Amyloidosis During the Past 20 Years

Introduction: Diagnostic and therapeutic advances have led to increased awareness of transthyretin cardiac amyloidosis (ATTR-CA). We sought to characterise the change in clinical phenotype of patients with ATTR-CA over the last 20-years. Methods: We studied 1967 patients diagnosed with ATTR-CA at the National Amyloidosis Centre (NAC) from 2002-2021. Results: Analysis by 5-year quartiles revealed a substantial incremental increase in patients diagnosed, with the most marked increases seen in wild-type ATTR. Increased diagnoses were accompanied by greater proportions of patients referred following bone scintigraphy and cardiac magnetic resonance imaging (3% vs 44% vs 67% vs 76%, P<0.001). Over time, median duration of symptoms prior to diagnosis diminished from 36-months between 2002-2006 to 12-months between 2017-2021 (P<0.001) and a greater proportion of patients had milder disease at the time of diagnosis across the 5-yearly quartiles (NAC stage 1: 34% vs 42% vs 44% vs 53%, P<0.001). The latter was associated with more favourable echocardiographic parameters of structure and function, including an incremental decrease in interventricular septal thickness(18.0±3.8mm vs 17.2±2.6mm vs 16.9±2.3mm vs 16.6±2.4mm, P=0.01), which was associated with improved survival. The improved survival associated with the year of diagnosis remained significant when censoring at trial or disease modifying medication start date (2012-2016 vs. 2017-2021: HR=1.05, 95%CI[1.03-1.07], P<0.001). Conclusions: Increased awareness and advances in cardiac imaging have been associated with a substantial increase in diagnosis of ATTR-CA and at a progressively earlier stage of the disease, which has contributed to improved survival in recent years. These changes may have important implications for initiation and outcome of therapy and urgently need to be factored into clinical trial design.