Cardiovascular magnetic resonance (CMR) with extracellular volume (ECV) mapping can effectively track changes in cardiac amyloid burden in transthyretin amyloid cardiomyopathy (ATTR-CM) and is independently associated with patient outcomes, according to a new prospective study.¹

This single-centre prospective study included 189 patients with ATTR-CM. The cohort was divided into an untreated group (n=119) and a group treated with patisiran (n=70). All patients underwent CMR at baseline, with follow-up scans at 1 and/or 2 years. The primary endpoint was the change in myocardial ECV, a marker of amyloid load. Response was categorised as progression (≥5% increase in ECV), stable (<5% change), or regression (≥5% decrease).

In the untreated group, there was a significant increase in mean ECV over time, rising by 4.1% at 1 year and 6.8% at 2 years. This was accompanied by a worsening of cardiac biomarkers and structural parameters. Disease progression, as measured by ECV, was observed in 36% of untreated patients at 1 year, increasing to 62% at 2 years.

In contrast, patients treated with patisiran showed no significant change in mean ECV at either 1 or 2 years. The vast majority of treated patients had stable disease, with 88% remaining stable at 1 year and 100% at 2 years. Structural parameters also remained stable in this group.

Crucially, the study found that a change in ECV was linked to prognosis. An increase in ECV of 5% or more after 1 year was independently associated with a higher risk of mortality, even after adjusting for known predictors like N-terminal pro-B-type natriuretic peptide (NT-proBNP) progression (hazard ratio 2.021; 95% confidence interval 1.081–3.781; p=0.028).

The findings suggest that CMR with ECV mapping is a valuable non-invasive tool for monitoring the natural history of ATTR-CM and assessing therapeutic response. The study authors concluded that “CMR with ECV mapping can track changes in cardiac amyloid burden and treatment response in ATTR-CM, with changes in ECV being independently associated with outcomes.”¹ This technique could play a significant role in clinical practice and future clinical trials by providing a direct measure of cardiac amyloid load, which may precede changes in functional capacity and clinical events.

References

1. Patel RK, Ioannou A, Sheikh A, et al. Transthyretin amyloid cardiomyopathy: natural history and treatment response assessed by cardiovascular magnetic resonance. Eur Heart J. 2025;46(46):5049–5058. https://doi.org/10.1093/eurheartj/ehaf412

2. Ruberg FL, Grogan M, Hanna M, et al. Transthyretin amyloid cardiomyopathy: JACC state-of-the-art review. J Am Coll Cardiol. 2019;73:2872–91. https://doi.org/10.1016/j.jacc.2019.04.003

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