Computed tomography-derived myocardial extracellular volume: a diagnostic marker for cardiac amyloidosis in transcatheter aortic valve implantation patients with biopsy confirmation

Abstract Background Transthyretin cardiac amyloidosis (ATTR-CA) appears to be prevalent in aortic stenosis (AS). The coexistence of ATTR-CA and severe AS is associated with an increased risk of hospitalization for heart failure after transcatheter aortic valve implantation (TAVI). The identification of ATTR-CA is of great clinical importance. In this study, we investigated the diagnostic value of computed tomography-derived myocardial extracellular volume (CT-ECV) for the diagnosis of biopsy-proven ATTR-CA. Methods From December 2022 to January 2024, we enrolled patients who underwent both TAVI and myocardial biopsy. CT-ECV was measured as part of routine CT imaging before TAVI and myocardial biopsy for definitive diagnosis of CA. Results Of 131 TAVI patients, 101 patients underwent myocardial biopsy. Eight patients (7.9%) were diagnosed with ATTR-CA. There were no significant differences in electrocardiographic parameters. On echocardiography, left ventricular ejection fraction (64 ± 16% vs. 65 ± 14%, p = 0.84) was similar between the 2 groups, whereas intraventricular septum and left ventricular posterior wall in diastole were thicker in the ATTR-CA group (15 ± 3mm vs. 13 ± 2mm, p = 0.04 and 14 ± 3mm vs. 12 ± 2mm, p <0.01, respectively). Significantly higher CT-ECV values were found in the ATTR-CA group than in the non-ATTR-CA group (32.6 ± 3.7% vs. 28.1 ± 3.7%, p = 0.001). Conclusions Patients with biopsy-proven ATTR-CA had high CT-ECV values. Routine CT-ECV evaluation before TAVI may be useful for the diagnosis of ATTR-CA.