Extracellular remodeling in patients with wild-type amyloidosis consuming epigallocatechin-3-gallate: preliminary results of T1 mapping by cardiac magnetic resonance imaging in a small single center study

T1 mapping by cardiac magnetic resonance imaging (CMR) is able to determine the extracellular volume fraction. Wild-type transthyretin amyloidosis (WT-ATTR) is characterized by extracellular amyloid deposition in the heart. Recent reports indicated a reduction of left ventricular (LV) myocardial mass in WT-ATTR after consumption of epigallocatechin-3-gallate, the main catechin in green tea. It remained unclear, whether reduction of LV myocardial mass reflects decrease of amyloid load or progressive atrophy of cardiomyocytes. This study included 7 male patients with CMR repetitively performed before and 12 months after daily consumption of green tea extract (600 mg epigallocatechin-3-gallate). Short axis slices as well as 2-, 3-, and 4-chamber views were acquired using SSFP sequences. T1 mapping was created out of 11 mid-ventricular short axis views with increasing inversion times using a single breath-hold modified look-locker inversion recovery sequence before and 15 min after Gadolinium contrast administration. After 12 months, a significant decrease of LV myocardial mass [198 (160; 212) vs. 180 (142; 204) g; p < 0.05] was observed. Moreover, a significant decrease of native [T1 1110 (1072; 1150) ms vs. 1080 (970; 1101), p < 0.05 or p = 0.03] was noticed. The calculated extracellular volume decreased in 5 patients (62.5 %) by 7 % and increased in 2 patients (37.5 %) by 9.5 %, in trend resulting in a (not significant) decrease of median ECV by 2.4 %. Left ventricular ejection fraction (LVEF) [57 (48; 65) vs. 55 (47; 64) %; p = 0.3] remained unchanged. This study provided further evidence of LV myocardial mass reduction in patients with WT-ATTR daily consuming green tea extract. Additionally, this study gave first insights into the histomorphological correlate of LV mass reduction using T1 mapping. LV mass reduction appeared to be rather due to a decrease of amyloid load than atrophy of cardiomyocytes.