Abstract 12974: Transthyretin Amyloid Cardiomyopathy Associated With the P.V142I Transthyretin Variant is an Inherently Aggressive Form of Transthyretin Amyloid Cardiomyopathy Associated With Significant Functional Impairment and Poor Prognosis

Abstract

Introduction: Transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly recognised cause of heart failure. 3-4% of individuals of African descent carry a TTR gene mutation encoding the p.V142I variant, a powerful risk factor for development of variant ATTR-CM; this equates to 1.6 million carriers in the USA. We report deep phenotyping in p.V142I ATTR-CM. Hypothesis: The phenotype of p.V142I ATTR-CM is an aggressive form of ATTR CM. Methods: A retrospective study of 395 patients with p.V142I ATTR-CM from the UK National Amyloidosis Centre. Patients were diagnosed at the Centre through a comprehensive evaluation comprising clinical and functional assessment, echocardiography, radionuclide scintigraphy, histology and biomarker analysis; a subgroup had cardiac magnetic resonance imaging. 395 wild-type ATTR-CM patients matched for independent predictors of prognosis (NAC Disease Stage, age, decade of diagnosis) were used as a comparator group. Results: At time of diagnosis, patients with p.V142I ATTR-CM had significant functional impairment by NYHA classification (NHYA ≥ III; 38.2%) and impairment of echocardiographic parameters; mean LVEF 43%, global longitudinal strain -9.1%, TAPSE 14.2mm, E/E prime 17.4, E/A ratio 2.47 with high frequency of at least moderate mitral (44%) and tricuspid (51%) regurgitation. Uni and multivariate cox regression analysis identified troponin T, TR, LVEF, TAPSE and lower systolic blood pressure as independent predictors of prognosis. Prognostic parameters and 5yr survival (27% v 46%, p<0.001) were significantly worse than in wtATTR-CM. Conclusion: p.V142I ATTR-CM has an aggressive phenotype characterised by functional impairment, regurgitant valvular disease and systolic impairment resulting in poor survival. LV systolic impairment, TAPSE, serum troponin and TR were independent predictors of survival, whereas LV wall thickness was not, suggesting as yet unrecognised disease mechanisms.