Monitoring and Treatment of Transthyretin Amyloidosis

Introduction to Monitoring

• The American College of Cardiology recommends regular monitoring of cardiac biomarkers (NT-proBNP, troponin) and echocardiography with strain measurements every 6 months to assess treatment response to tafamidis in patients with transthyretin amyloidosis 1, 2, 3

Laboratory and Echocardiography Monitoring

• Patients should undergo NT-proBNP and troponin T or I testing, complete blood count, basic biochemistry, and renal function (eGFR) assessment every 3-6 months 1, 2
• Transthoracic echocardiography with strain measurements and Holter ECG should be performed every 6 months to monitor for arrhythmias 1, 3

Clinical Assessment and Functional Capacity

• Patients should undergo NYHA functional class assessment every 6 months, and optionally, 6-minute walk distance test and Kansas City Cardiomyopathy Questionnaire (KCCQ) 1, 2, 3
• The American College of Cardiology recommends anticoagulation regardless of CHA₂DS₂-VASc score 2, 3, 4

Treatment Expectations and Outcomes

• Tafamidis prevents but does not reverse amyloid deposition, and benefits typically emerge after 18 months of treatment 2
• Declining functional status (NYHA class progression) is a concern and requires close monitoring 2, 3
• New arrhythmias, particularly atrial fibrillation, should be monitored closely 1, 3
• Reduced frequency of cardiovascular-related hospitalizations is a desired outcome 2
• Patients with NYHA Class I-II typically show the greatest benefit from tafamidis, while those with NYHA Class III may require more frequent monitoring, and those with NYHA Class IV have limited data on benefit 2, 3
• The American College of Cardiology suggests that future treatment may involve concurrent administration of TTR silencing and stabilizing agents, with circulating markers such as prealbumin, cardiac troponins, natriuretic peptides, and kidney function being important for monitoring, and imaging markers like echocardiographic global longitudinal strain and CMR extracellular volume fraction being useful for diagnosis 5

Diagnostic Tests

• The following diagnostic tests are recommended:

6, 7

• Abdominal fat aspiration is a preferred initial site for biopsy, with a sensitivity of 84% for AL-CM, 45% for ATTRv-CM, and 15% for ATTRwt-CM 6
• Cardiac biomarkers, such as BNP/NT-proBNP, have a sensitivity of 93% and specificity of 90% for diagnosing cardiac conditions, as recommended by the American Heart Association and American College of Cardiology 6, 5

Treatment Options

• The American College of Cardiology recommends daratumumab combined with cyclophosphamide, bortezomib, and dexamethasone (Dara-CyBorD) as first-line treatment for AL amyloidosis, which achieves high rates of deep hematologic responses 5
• CyBorD alone (cyclophosphamide, bortezomib, dexamethasone) is an alternative option for patients who cannot tolerate daratumumab 5
• TTR gene silencing approaches and TTR stabilizers, such as tafamidis, are used to suppress TTR protein production and prevent TTR tetramer dissociation into fibrils, reducing cardiovascular mortality and hospitalization, with tafamidis being well-tolerated and having no significant side effects reported in clinical trials 5
• Tafamidis is the only FDA-approved treatment for ATTR cardiomyopathy, with a recommended dosage of 80 mg VYNDAQEL or 61 mg VYNDAMAX 5, 1, 8
• The following treatment options are recommended:

5, 1, 8

Symptom Management and Palliative Care

• Diuretics are used judiciously as the mainstay of symptom management, although the specific details are not provided here, the importance of careful medication management is emphasized, with medications like β-blockers, digoxin, calcium channel blockers, and ACE inhibitors/ARBs to be used with caution or avoided due to potential adverse effects 5, 6
• Anticoagulation is indicated for atrial fibrillation, embolic stroke/TIA, or intracardiac thrombus, but benefits must be weighed against increased bleeding risk in amyloid angiopathy 6
• Palliative care should be integrated early in the disease course for assessment of goals, values, and preferences, symptom management, psychological relief, and support system for family, with patients referred to palliative care at any stage when physical symptoms or emotional/spiritual distress interfere with quality of life 5

Advanced Therapies and Transplantation

• Heart transplantation is considered for end-stage disease, often with combined heart-liver transplantation for ATTRv, with a 5-year survival rate of 50-80% 5
• Liver transplantation can cure the disease process as TTR protein is synthesized in the liver, with a 5-year survival rate of 50-80% for combined heart and liver transplantation 6
• High-dose melphalan followed by autologous stem cell transplantation (HDM/SCT) is an option for eligible patients without significant cardiac involvement, with a treatment-related mortality of approximately 3%, 70% achieving very good partial hematologic response or better, and median survival >15 years in those achieving complete response 5, 6

Multidisciplinary Care

• Management of cardiac amyloidosis requires collaboration between cardiologists, hematologists, neurologists, nephrologists, and palliative care specialists, with the goal of providing comprehensive care and improving patient outcomes 5
• Treatment-related mortality is a significant concern, particularly in patients with advanced cardiac involvement, according to the American College of Cardiology 5