Serial extracellular volume quantification using cardiac magnetic resonance imaging in transthyretin amyloidosis patients treated with tafamidis.

Abstract

Cardiac transthyretin amyloidosis (ATTR CA) has been increasingly recognized as an important heart failure (HF) entity, and cardiac magnetic resonance (CMR) imaging is a mainstay in the clinical evaluation of this disease. However, studies evaluating the prognostic values of longitudinal data in ATTR CA patients with disease-modifying therapies are lacking. We aimed to assess the prognostic significance of serial quantification of extracellular volume (ECV) in ATTR CA patients treated with tafamidis. The present study included ATTR CA patients who received ≥ 3 months of tafamidis treatment and underwent baseline and CMR, including ECV quantification. The primary endpoint was a composite of all-cause mortality, cardiac transplantation, or hospitalization due to HF. Between June 2016 and June 2020, 54 patients were included in the present analysis and were representative of a typical ATTR CA cohort (median age: 76.7 years, male participants: 79.6%). The median time on tafamidis before follow-up CMR was 6.0 months (interquartile range (IQR): 6.0-8.3). Participants depicted typical structural changes for ATTR CA patients with markedly elevated ECV (51.4% (IQR: 41.3-57.6), normal range: 20-32%) and myocardial ventricular hypertrophy (intraventricular septum: 19 mm (16.0-22.0), normal range: 5-12 mm). Change of ECV was the only parameter among clinical, laboratory, and CMR parameters that was independently associated with the composite endpoint (HR: 1.077, 95% CI: 1.013-1.145, p = 0.017). Change of ECV was the only predictor of adverse outcome among clinical, laboratory, and imaging parameters in our cohort of tafamidis-treated ATTR CA patients. Question What is the prognostic significance of serial ECV quantification in transthyretin amyloidosis patients on tafamidis treatment? Findings Change of ECV is a strong predictor of a combined endpoint consisting of all-cause mortality, cardiac transplantation, or hospitalization due to HF. Clinical relevance Patients with increasing ECV might potentially benefit from a change in amyloid-specific treatment to a different agent.