**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Ahmad Masri 
Oregon Health & Science University, Portland, OR 
Multicenter study (OHSU, Cleveland Clinic, University of Pittsburgh Medical Center, Columbia University, University of Missouri at Kansas City)

**Main Body of the Abstract**
Introduction: The natural history of transthyretin amyloid cardiomyopathy (ATTR-CM) is rapidly evolving. We investigated the change in patients and disease characteristics over a 20 year period.
Methods: We enrolled 1,168 patients with ATTR-CM who were diagnosed between 2001 and 2021 at 5 amyloidosis centers in the US. Patients were presented using pre-specified 4 eras: pre-2010, 2010-2013, 2014-2017, and 2018-2021. Baseline refers to the date of ATTR-CM diagnosis.
Results: We enrolled 41 (3.5%, 12.2% women), 151 (12.9%, 18.5% women), 361 (30.9%, 13% women), and 615 (52.7%, 13.8% women) patients in pre-2010, 2010-2023, 2014-2017, and 2018-2021, respectively. Over time, age, wild-type ATTR-CM, NYHA class I and II, and tafamidis use increased significantly (all p<0.05), Table. While the total number of Black patients diagnosed with ATTR-CM increased overtime, the proportion from the total diagnosed patients decreased, p<0.05. NT-proBNP, eGFR and NAC Stages did not change significantly overtime (p>0.05), while Columbia Stages significantly changed (p<0.05). The ATTR-CM diagnosis method evolved from 100% using endomyocardial biopsy pre-2010 to 90% using non-invasive bone scintigraphy criteria (p<0.05). Due to early access programs and/or commercial availability, tafamidis use significantly increased in the 2018-2021 era, and time from ATTR-CM diagnosis to receiving tafamidis was 2.3 months (0.7, 6.5).
Conclusion: Over 20 years, majority of ATTR-CM patients and disease characteristics changed significantly. The natural history of ATTR-CM is evolving, tied to such changes in addition to the introduction of novel therapies. We provide useful data that will aid in the understanding of current era outcomes and design of clinical trials.



Evolution of Transthyretin Amyloid Cardiomyopathy Characteristics Over a 20 Year Period: A Multicenter Study of 1,168 Patients PC71 (#428)

We invite you to attend the XIX International Symposium on Amyloidosis to be held in Rochester, MN.

This symposium is organized as a hybrid meeting (with the focus on in-person) held from Sunday, May 26 through Thursday, May 30, 2024.

Together with the ISA Board and members of Mayo Clinic, a very attractive scientific hybrid program is being planned. The program will cover a variety of types of systemic amyloidosis: ATTR (hereditary and wild-type), AL (light-chain), AA and less frequent forms. There will be key lectures, specific symposia including those company sponsored, oral presentations and poster sessions of accepted abstracts.

COURSE DESCRIPTION
This program will provide a comprehensive review of state-of-the-art education in systemic amyloidosis: basic science, pathophysiology, diagnosis, current and emerging treatments. Scientific presentations will include competitive oral and poster abstracts. The rapid evolution of scientific discovery and expanding treatment options has created tremendous interest in the field and this meeting will fill and important gap in educating scientists and clinicians.