# Machine-learning approach on echocardiography to improve the detection of transthyretin amyloid cardiomyopathy: GRAAL algorithm

## TL;DR

A machine-learning algorithm called GRAAL improves detection of a heart condition called transthyretin amyloid cardiomyopathy using echocardiography data.

## Contribution

The GRAAL algorithm combines key echocardiographic variables to enhance detection accuracy of transthyretin amyloid cardiomyopathy.

## Key findings

- ATTR-CM patients showed lower systolic function and more apical longitudinal sparing compared to controls.
- Machine learning identified RVFWT, RALS, GLS, and LV mass index as key variables for detecting ATTR-CM with high accuracy.
- The GRAAL algorithm improved diagnostic accuracy over existing guidelines and performed well in a validation cohort.

## Abstract

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly recognized cause of heart failure, yet detection remains challenging due to its echocardiographic similarities with age- and hypertension-related cardiac remodelling.

We retrospectively included 260 patients (76.5 ± 12.9 years old, 59.6% male) referred for suspected ATTR-CM. A supervised machine-learning diagnosis algorithm differentiating patients with (n = 111) and without (n = 149) ATTR-CM based on echocardiographic data, and subsequently validated in an external multicentre cohort of 454 patients (76.3 ± 12.6 years old, 69.1% male). Patients with ATTR-CM had a lower systolic function [left ventricular ejection fraction 47 ± 11 vs. 54 ± 12%, P < 0.00; global longitudinal strain (GLS) 11.0 ± 3.7 vs. 14.1 ± 4.5%, P < 0.001] and more significant relative apical longitudinal sparing (RALS) (1.5 ± 1.2 vs. 0.9 ± 0.4, P < 0.001) compared with controls. Machine learning identified right ventricular free wall thickness (RVFWT), RALS, GLS, and LV mass index as key variables for detecting ATTR-CM [AUC 0.90 (0.86–0.94); P < 0.001]. These variables enhanced diagnostic accuracy compared with the increased wall thickness guideline score [increase in C-index of 0.17 (0.11–0.23), P < 0.001]. Diagnostic performance was confirmed in the validation multicentre cohort [AUC of 0.83 (0.80–0.87), P < 0.001]

The simple GRAAL algorithm (GLS, RVFWT, Apical spAring, LV Mass) enhances detection accuracy for ATTR-CM and improves patient selection for bone scintigraphy.

Graphical AbstractFor image description, please refer to the figure legend and surrounding text.