Microvascular dysfunction in patients with transthyretin cardiac amyloidosis evaluated by 13N-ammonia positron emission tomography–computed tomography: is it an early marker of the disease?

PURPOSE: gene mutations, with and without cardiac involvement. This study is the first to assess coronary flow reserve (CFR) in this population before overt cardiac amyloidosis (CA) is detectable by conventional imaging. METHODS: gene mutations. RESULTS: < 0.001). Global CFR inversely correlated with age, functional class, troponin, and B-type natriuretic peptide while positively correlating with the 6-minute walk test distance, mean blood pressure, and global longitudinal strain. Receiver operating characteristic curve analysis identified an optimal cutoff value of global CFR < 2.58, yielding a sensitivity of 100% and a specificity of 75% for detecting cardiac involvement. CONCLUSION: In patients with ATTR CA, coronary microvascular dysfunction emerges as a clinically relevant marker of cardiac involvement, even in the absence of structural abnormalities or obstructive coronary disease. CLINICAL SIGNIFICANCE: CFR assessment may aid in diagnostic suspicion, risk stratification, and understanding of angina symptoms in this population.