Abstract 10514: Inguinal Fat Tissue Biopsy to Identify Transthyretin Amyloidosis in Patients Undergoing Transcatheter Aortic Valve Implantation

Abstract

Background: Several studies have recently reported that transthyretin (ATTR) amyloidosis is present in patients with aortic stenosis (AS). This study aimed to 1) examine the utility of inguinal fat tissue biopsy in AS patients who underwent transcatheter aortic valve implantation (TAVI) to detect ATTR amyloidosis, 2) compare clinical characteristics between AS patients with ATTR (ATTR group) and those without ATTR (non-ATTR group). Methods and Results: We prospectively analyzed consecutive 56 patients who underwent transfemoral TAVI from December 2018 to December 2020 in our hospital. To screen ATTR in these patients, we performed inguinal fat tissue biopsy from cut down or puncture site during TAVI. Of 56 AS patients, 5 (8.9%) patients were diagnosed as ATTR by inguinal fat biopsy. Compared with non-ATTR group, ATTR group presented higher levels of B-type natriuretic peptide (BNP, 566.4 vs. 242.5 ng/ml, P=0.0045), higher levels of troponin I (0.053 vs. 0.024 ng/ml, P=0.003), lower left ventricular ejection fraction (LVEF, 49.3 vs. 60.3%, P=0.0035), larger left ventricular mass index (150.2 vs. 115.5 g/m 2 , P=0.019), larger aortic valve area (0.84 vs. 0.63 cm 2 , P=0.029) and lower peak velocity of aortic valve (3.8 vs. 4.4 m/s, P=0.041). In contrast, age, sex, STS score, clinical frailty scale, prevalence of diabetes, chronic kidney disease and AF, levels of albumin, and eGFR were comparable between the two groups. Electrocardiogram and other echocardiographic parameters including interventricular septal wall thickness, posterior wall thickness, stroke volume index and E/A ratio did not differ between the two groups. Although TAVI was successfully completed in all patients, the incidence of life-threatening bleeding and 30-day readmission was higher in ATTR group than in non-ATTR group (40.0 vs. 5.9%, P=0.011 and 20.0 vs. 0.0%, P=0.001). There was no difference in occurrence of myocardial infarction, stroke, acute kidney injury, major vascular complication, pacemaker implantation and 30-day mortality. Conclusions: In AS patients, especially in those with increased BNP and troponin I levels and low-flow low-gradient pattern, ATTR should be considered. In this population, inguinal fat tissue biopsy is a novel and safe approach to identify ATTR.