**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.**
Daniel Davies. Mayo Clinic, Rochester, MN, U.S.A.

**Main Body of the Abstract**
Background: A simple, six-variable score was developed to identify patients with heart failure with preserved ejection fraction (LVEF ≥ 40%) at increased risk of transthyretin amyloid cardiomyopathy (ATTR-CM). We sought to determine the score's performance in patients with reduced ejection fraction (HFrEF, LVEF < 40%).
Methods: The ATTR-CM score was applied to patients with LVEF <40% undergoing 99mtechnetium-pyrophosphate scintigraphy (PYP) for suspicion of ATTR-CM at Mayo Clinic (2013-2023). The score, based on clinical and echocardiographic variables (age [+2 if 60-69 y.o., +3 if 70-79 y.o., and +4 if ≥80 y.o.], male sex [+2], EF < 60% [+1], posterior wall thickness of ≥ 12mm [+1], relative wall thickness > 0.57 [+2], and hypertension history [-1]) was calculated using an additive point system. A score ≥ 6 indicated "high risk" for ATTR-CM. Standard ROC methods were used to assess performance.
Results: A LVEF <40% was present in 204 of 2239 patients (median age 73, 84% male, 43% ATTR-CM prevalence), of whom 64% had a "high risk" score. The ATTR-CM patients were older, less likely hypertensive, and had thicker left ventricles (see table). The score exhibited strong discrimination (AUC 0.83), sensitivity 90%, specificity 55%, and excellent calibration (Hosmer-Lemeshow p=0.25). Precision recall curves indicated clinically useful classification (positive predictive value > 60% at score cutoff ≥ 6).
Conclusions: The ATTR-CM score showed strong predictive performance in HFrEF patients undergoing PYP for suspicion of ATTR-CM. This highlights the utility of the ATTR-CM score irrespective of ejection fraction, aiding in identifying candidates for definitive diagnostic testing.



**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.**
Daniel Davies. Mayo Clinic, Rochester, MN, U.S.A.

**Main Body of the Abstract**
**Background**: A simple, six-variable score was developed to identify patients with heart failure with preserved ejection fraction (LVEF ≥ 40%) at increased risk of transthyretin amyloid cardiomyopathy (ATTR-CM). We sought to determine the score's performance in patients with reduced ejection fraction (HFrEF, LVEF < 40%).
**Methods**: The ATTR-CM score was applied to patients with LVEF <40% undergoing 99mtechnetium-pyrophosphate scintigraphy (PYP) for suspicion of ATTR-CM at Mayo Clinic (2013-2023). The score, based on clinical and echocardiographic variables (age [+2 if 60-69 y.o., +3 if 70-79 y.o., and +4 if ≥80 y.o.], male sex [+2], EF < 60% [+1], posterior wall thickness of ≥ 12mm [+1], relative wall thickness > 0.57 [+2], and hypertension history [-1]) was calculated using an additive point system. A score ≥ 6 indicated "high risk" for ATTR-CM. Standard ROC methods were used to assess performance.
**Results**: A LVEF <40% was present in 204 of 2239 patients (median age 73, 84% male, 43% ATTR-CM prevalence), of whom 64% had a "high risk" score. The ATTR-CM patients were older, less likely hypertensive, and had thicker left ventricles (see table). The score exhibited strong discrimination (AUC 0.83), sensitivity 90%, specificity 55%, and excellent calibration (Hosmer-Lemeshow p=0.25). Precision recall curves indicated clinically useful classification (positive predictive value > 60% at score cutoff ≥ 6).
**Conclusions**: The ATTR-CM score showed strong predictive performance in HFrEF patients undergoing PYP for suspicion of ATTR-CM. This highlights the utility of the ATTR-CM score irrespective of ejection fraction, aiding in identifying candidates for definitive diagnostic testing.



Prediction of Transthyretin Amyloid Cardiomyopathy in Heart Failure with Reduced Ejection Fraction Using the ATTR-CM Score PB110 (#274)

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.