How should anticoagulation be managed in patients with amyloidosis?

Anticoagulation Management in Amyloidosis

Anticoagulation is recommended for all patients with cardiac amyloidosis and atrial fibrillation regardless of CHA₂DS₂-VASc score to prevent ischemic stroke and thromboembolism. 1, 2

Risk Assessment in Amyloidosis Patients

Amyloidosis patients face unique thrombotic and bleeding risks:

Thrombotic Risk Factors

• Cardiac involvement: Particularly important in AL amyloidosis
• Atrial fibrillation: Occurs in 20-75% of patients with systemic amyloidosis 3
• Atrial mechanical standstill: Can occur even in sinus rhythm due to amyloid infiltration 1
• Intracardiac thrombi: Present in up to 30% of AL amyloidosis patients 3
• Nephrotic syndrome: Especially in AL amyloidosis 4, 5
• Immunomodulatory drug therapy: Increases thrombotic risk 4

Bleeding Risk Factors

• Amyloid angiopathy: Causes vessel fragility and impaired vasoconstriction 6
• Factor X deficiency: Particularly in AL amyloidosis 7
• Gastrointestinal involvement: Common site of bleeding 6
• Coagulation inhibitors: Present in up to 40% of AL amyloidosis patients 7
• Renal dysfunction: Common in amyloidosis 4

Anticoagulation Algorithm

1. For Patients with Cardiac Amyloidosis and Atrial Fibrillation

• Initiate anticoagulation regardless of CHA₂DS₂-VASc score 1, 2
• Direct oral anticoagulants (DOACs) are recommended as first-line therapy unless contraindicated 1
• Vitamin K antagonists (VKAs) with target INR 2.0-3.0 if DOACs are contraindicated 1

2. For Patients with Cardiac Amyloidosis in Sinus Rhythm

• Consider screening for intracardiac thrombi with transesophageal echocardiography 1
• Initiate anticoagulation if intracardiac thrombus is detected 1
• Consider anticoagulation even without thrombus if severe atrial dysfunction is present 1

3. For Patients with History of Embolic Events

• Initiate anticoagulation regardless of rhythm 1
• Do not add antiplatelet therapy to anticoagulation for recurrent embolic stroke prevention 1

4. For Patients with Nephrotic Syndrome due to Amyloidosis

• Anticoagulation is generally not recommended specifically for nephrotic syndrome in the absence of other indications 1
• Consider anticoagulation if serum albumin <3 g/dL (4.3x increased VTE risk) 5

Special Considerations

Bleeding Risk Management

• Assess for factor X deficiency before initiating anticoagulation in AL amyloidosis 6, 7
• Evaluate for GI amyloid involvement which increases bleeding risk 6
• Monitor renal function as it affects both bleeding risk and drug dosing 4

Medication Selection and Dosing

• Use standard DOAC dosing unless specific dose-reduction criteria are met 1
• Avoid underdosing DOACs as this increases thromboembolic risk 1
• Consider maintaining VKA therapy rather than switching to a DOAC in patients ≥75 years with stable INRs and polypharmacy 1

Monitoring

• Regular reassessment of thrombotic and bleeding risks is essential 1
• Evaluate for thrombi before cardioversion in patients with atrial fibrillation 3

Common Pitfalls to Avoid

1. Do not withhold anticoagulation in cardiac amyloidosis patients with atrial fibrillation based solely on bleeding concerns
2. Do not add antiplatelet therapy to anticoagulation for stroke prevention 1
3. Do not use symptom-based questionnaires alone for screening obstructive sleep apnea in AF patients 1
4. Do not switch between anticoagulants without clear indication in patients with recurrent embolic events 1
5. Do not underdose DOACs unless patients meet specific criteria for dose reduction 1

By following these guidelines, clinicians can optimize anticoagulation management in amyloidosis patients to reduce thromboembolic events while minimizing bleeding complications.