Transthyretin (ATTR) Cardiac Amyloidosis with Kidney Involvement

Introduction: Amyloidosis refers to the extracellular deposition of fibrils arising from a variety of serum proteins. These fibrils adopt a beta-pleated sheet configuration that leads to characteristic histologic changes. Amyloid deposits can occur in a variety of organs, but morbidity and mortality from amyloid deposition most commonly occur when the heart, kidney, liver, or autonomic nervous system are affected. ATTR-CA (transthyretin) leads to a progressive restrictive physiology with reduced stroke volume, decreased compliance, and compromised cardiac output. Studies directly addressing the benefit of traditional heart failure (HF) medical therapy for ATTR-CA remain limited. Case Description: 77 years old male known to have history of hypertension, dyslipidaemia, chronic kidney disease stage 3, he was following with cardiology in 2022 for symptoms of shortness of breath and chest pain and his ECHO showed sever aortic regurgitation and mild left ventricle global systolic dysfunction with restrictive filling pattern but no aortic stenosis. Two years later he was admitted with worsening renal function, anasarca and right arm cellulitis with Methicillin sensitive staphylococcus aureus (MSSA) bacteraemia. His ECHO showed sever aortic stenosis this time. His urine protein was negative during the 2 years follow up period. He was started on haemodialysis and underwent Cardiac scintigraphy which was strongly suggestive of Transthyretin amyloidosis. The patient was started on Tafamidis which prevents cleavage of transthyretin tetramers and may reduce deposition of amyloid. The patient currently on twice per week haemodialysis and his creatinine 150-200 micromole/L and on watchful followup for his renal function recovery. Discussion: ATTR AMYLOIDOSIS In patients with ATTR cardiac amyloidosis and New York Heart Association (NYHA) functional class I to III HF symptoms, treatment with tafamidis is recommended rather than no disease-specific therapy. Tafamidis is given as tafamidis meglumine 80 mg daily or as tafamidis 61 mg daily. Tafamidis (either formulation) does not require specific monitoring and is continued indefinitely. The high cost of tafamidis is a major barrier to therapy. Tafamidis reduced the rate of mortality compared with placebo and reduced the rate of cardiovascular-related hospitalizations, it also reduced the rate of decline in six-minute walk distance and Kansas City Cardiomyopathy Questionnaire-Overall Summary.