Abstract 10257: Diagnostic Yield of Screening and Associated Factors for Transthyretin Cardiac Amyloidosis in Severe Aortic Stenosis

Abstract

Introduction: Transthyretin cardiac amyloidosis (ATTR-CA) has been associated with severe aortic stenosis (AS), with some studies finding up to 20% of patients who undergo transcatheter aortic replacement (TAVR) have ATTR-CA. New therapies for ATTR-CA have brought significant interest in identifying patients at high risk for this disease. The purpose of this study was to prospectively evaluate the yield of universal testing for ATTR-CA in older patients with severe AS. Methods: All patients ≥ 70 years with severe, native, and degenerative AS seen in valve clinic for evaluation of TAVR were referred for technetium-99m pyrophosphate cardiac scintigraphy (PYP scan). Diagnosis was made via a combination of planar grade, heart to contralateral lung ratio, and single positron emission computed tomography/computed tomography. Patients with a positive PYP scan were referred for appropriate laboratory testing to rule out AL amyloidosis. Clinical and echocardiographic factors were correlated with the PYP result. Results: Over a 12-month period, 787 patients with severe AS were screened of which 543 met the inclusion criteria. Of these patients, 298 underwent a PYP scan with 232 not undergoing the scan for logistical and scheduling issues during the pandemic. The positivity rate was 4.3% (13/298). Patients with a positive PYP scan had higher rates of carpal tunnel syndrome (54% vs 14%, p <0.001), abnormal global longitudinal strain (> -18%) (100% vs 69%, p=0.044), low stroke volume index (≤35 ml/m 2 ) (92% vs 42%, p<0.001), thick intraventricular septum ≥ 1.1 cm (100% vs 79%, p=0.07), and abnormal left ventricular mass index (83% vs 46%, p=0.010). Conclusions: The prevalence of ATTR-CA in severe AS is lower than cited in previous studies, likely due to the expanded indication for TAVR. A multiparametric diagnostic algorithm or risk score for ATTR-CA in AS could enhance the yield of screening, reduce cost and unnecessary radiation, and result in more rapid treatment of amyloidosis.