Prognostic parameters and detection of cardiac amyloidosis with hybrid ¹⁸F-Florbetaben-PET/MRI: an exploratory observational study.

Abstract

Positron emission tomography (PET) with amyloid-binding tracers was shown to have high sensitivity for the detection of both transthyretin (ATTR) and light-chain (AL) cardiac amyloidosis (CA). Recent studies describe prognostic value of imaging biomarkers from bone scintigraphy and ¹⁸F-Florbetapir. The aim of this study was to evaluate the value of imaging biomarkers from ¹⁸F-Florbetaben PET, cardiac magnetic resonance (CMR), and echocardiography imaging for prediction of major adverse cardiac events (MACE) in comparison to serum biomarkers in patients with different types of CA. Patients who underwent cardiac ¹⁸F-Florbetaben PET/MRI were prospectively enrolled and received clinical follow-up for up to 36 months and MACE were reported (NCT07154381). Scans were reported by two blinded, nuclear medicine physicians. Imaging biomarkers including average retention index (RI), T1 mapping/ extracellular volume (ECV) and serological markers were estimated and their association with MACE free survival was analyzed. Twenty-one patients with confirmed CA were enrolled. MACEs were reported in 14 of 21 patients (66.7%). Higher average RI was the only imaging biomarker that was a significant predictor for MACE in uni- and multivariate analysis (HR = 4.02, 95%CI: 1.25-12.9, p < 0.05). N-terminal pro-B-type natriuretic peptide (NT-proBNP) was a significant predictor in uni- but not in multivariate analysis. Patients with AL-CA showed a higher rate of MACE than patients with other subtypes. Integrated ¹⁸F-Florbetaben PET/MR allows diagnosis, subtype differentiation and outcome predication of CA. The average RI was the only significant and independent prognostic imaging biomarker of MACE. Future prospective studies are warranted to investigate benefits for patient management and risk assessment in larger cohorts.