In a patient with transthyretin amyloid cardiomyopathy on acoramidis (Attruby) 712 mg twice daily who also has chronic heart failure and is taking furosemide (Bumex) 2 mg daily, what is the recommended management?

Management of ATTR-CM Patient on Acoramidis with CHF on Bumetanide

Continue acoramidis 712 mg twice daily as prescribed and maintain the current bumetanide 2 mg daily dose, with close monitoring for volume status and renal function. 1

Disease-Modifying Therapy

Acoramidis (Attruby) should be continued at the FDA-approved dosage of 712 mg orally twice daily, taken with or without food 1. This TTR stabilizer has demonstrated significant benefits in the ATTRibute-CM trial, including:

• Reduced all-cause mortality and cardiovascular hospitalizations (win ratio 1.8, P<0.001) 2
• Improved functional capacity (6-minute walk distance)
• Better quality of life (KCCQ scores)
• Stabilization of NT-proBNP levels 2

The drug is well-tolerated with no contraindications and minimal drug interactions 1. The most common adverse effects are mild gastrointestinal symptoms (diarrhea 11.6%, upper abdominal pain 5.5%) that rarely require discontinuation 1.

Heart Failure Management with Diuretics

Bumetanide Dosing Strategy

The current dose of 2 mg bumetanide daily (equivalent to approximately 80 mg furosemide) represents a moderate diuretic load 3. This is appropriate for initial management, but requires individualized titration based on:

• Volume status assessment: Daily weights, orthostatic vital signs, jugular venous pressure, peripheral edema
• Renal function monitoring: Acoramidis causes a predictable mean increase in serum creatinine of 0.2 mg/dL and decrease in eGFR of 8.2 mL/min/1.73m² within 4 weeks, which stabilizes and is reversible 1
• Symptom control: Dyspnea, exercise tolerance, congestion

Critical Considerations for ATTR-CM Diuresis

ATTR-CM patients have restrictive physiology and frequent autonomic dysfunction, creating a narrow therapeutic window 4. Small changes in preload can precipitate:

• Hypotension (especially orthostatic)
• Renal injury
• Low cardiac output symptoms

Bumetanide is preferred over furosemide in ATTR-CM when absorption is uncertain due to its more predictable bioavailability 4. The current 2 mg dose should be maintained unless:

• Escalate if: Persistent congestion, weight gain >2-3 lbs in 24 hours, worsening dyspnea
• Reduce if: Orthostatic hypotension, rising creatinine beyond the expected acoramidis effect, hypovolemic symptoms

Prognostic Implications

Higher diuretic doses predict worse mortality in ATTR-CM 3. In a French national database study of 7,804 ATTR-CM patients, diuretic dosage emerged as a pivotal prognostic indicator (HR 1.380,95% CI 1.315-1.449) 3. This underscores the importance of:

• Optimizing disease-modifying therapy to reduce diuretic requirements over time
• Avoiding excessive diuresis that may worsen outcomes
• Regular reassessment of diuretic needs

Additional Heart Failure Therapies to Consider

While the question focuses on diuretics, mineralocorticoid receptor antagonists (MRAs) and SGLT2 inhibitors show the best tolerability and potential benefit in ATTR-CM 4, 5:

• MRAs: Better tolerated than beta-blockers or ACE inhibitors/ARBs in ATTR-CM, with favorable observational associations 4
• SGLT2 inhibitors: Emerging real-world data suggest good tolerability with hypothesis-generating signals toward fewer HF events 4, 5

Beta-blockers and renin-angiotensin system inhibitors are frequently poorly tolerated in ATTR-CM due to restrictive physiology and autonomic dysfunction 4. These should only be used if there are compelling indications and with careful monitoring.

Monitoring Protocol

Within First 4 Weeks of Acoramidis:

• Serum creatinine and eGFR to establish new baseline (expect 0.2 mg/dL increase in creatinine) 1
• Volume status assessment
• Blood pressure including orthostatic measurements

Ongoing Monitoring:

• Monthly weights and symptom assessment
• Renal function every 3 months or with diuretic changes
• NT-proBNP levels to track disease progression 2
• Screen for extracardiac manifestations (neuropathy, GI symptoms, musculoskeletal issues) 6, 7

Common Pitfalls to Avoid

1. Over-diuresis: ATTR-CM patients are preload-dependent; aggressive diuresis can cause symptomatic hypotension and renal dysfunction
2. Attributing all creatinine rise to diuretics: Remember acoramidis causes a predictable, reversible increase in creatinine within 4 weeks 1
3. Using salt tablets or fludrocortisone for orthostatic hypotension: These are poorly tolerated in heart failure 6
4. Discontinuing acoramidis for mild GI symptoms: Most are mild and resolve without stopping therapy 1