Surveillance for disease progression of transthyretin amyloidosis after heart transplantation in the era of novel disease modifying therapies

Background: Heart Transplantation (HT) is a rational therapy for advanced transthyretin cardiac amyloidosis (ATTR-CA), but the impact of ongoing amyloid deposition is not well defined. We evaluated a cohort of patients who underwent HT for ATTR-CA to determine the incidence of de novo or progression of post-HT ATTR deposition. Methods: All patients who were followed post-HT for ATTR-CA at our center were included. Baseline demographics and post-HT manifestations of TTR deposition were collected. All patients completed the Composite Autonomic Symptom Score (COMPASS-31 quantifies autonomic symptoms, with a higher score [0-100] indicating more severe autonomic dysfunction) and Polyneuropathy Disability Score (PND, range from 0 [asymptomatic] to IV [confined to wheelchair/bed]) questionnaires. Results: Twelve patients (5 wild-type, 7 variant [6 p.Val142Ile, 1 p.Thr80Ala]) were included. Mean age at HT was 64.6 (SD: 4.8) years, 83.3% male, and 50% Black. At a median of 4.0 years (IQR 2.4, 5.9) post-HT, 8 patients had symptoms of ATTR deposition (5 with gastrointestinal involvement, 4 orthopedic and 4 neurologic), with 4 patients having ≥2 body systems involved. There were no patients with recurrent cardiac involvement. Median COMPASS-31 score was 17.3 (IQR 11.3, 23.5) at 3.9 years (IQR 2.4, 5.9) post-HT. Four patients had a PND score of stage 1 (sensory disturbance), 1 patient was stage 2 (impaired walking) and 1 patient stage 3b (required a walking aid). Conclusions: More than 50% of patients had evidence of progressive or de novo ATTR deposition post-HT, impairing quality of life despite a well-functioning cardiac allograft. These observations highlight an unmet need to establish the role of formal surveillance and treatment of TTR using TTR disease-modifying therapies, which may maintain or improve quality of life post-HT for ATTR-CA.