Is aspirin indicated in the treatment of hypertrophic cardiomyopathy?

Aspirin in Hypertrophic Cardiomyopathy: Role and Recommendations

Aspirin is not indicated as a primary therapy in hypertrophic cardiomyopathy (HCM) and should be reserved only for patients who cannot or will not take oral anticoagulants when atrial fibrillation is present, as its efficacy in HCM is unestablished. 1, 2

Anticoagulation in HCM with Atrial Fibrillation

Atrial fibrillation (AF) is a common complication in HCM and significantly increases the risk of thromboembolism. The management approach is clear:

• First-line therapy: Vitamin K antagonists (warfarin) with target INR 2.0-3.0 are strongly recommended for all HCM patients who develop AF (paroxysmal, persistent, or permanent) 1, 2
• Important note: Even patients with short episodes of AF should receive anticoagulation due to the high thromboembolic risk in HCM 1, 2
• Risk assessment: Unlike other cardiac conditions, the CHA₂DS₂-VASc score is not recommended for risk stratification in HCM patients with AF 1, 2
• Aspirin's role: Aspirin should be reserved only for patients who cannot or will not take oral anticoagulants 1, 2

Aspirin in Other HCM Contexts

Outside of AF management, the evidence for aspirin in HCM is limited:

• There is some research suggesting that platelet aggregation correlates with left ventricular hypertrophy severity and episodes of silent myocardial ischemia in HCM patients 3
• One older study reported that long-term aspirin administration reduced spontaneous and induced platelet aggregation in HCM patients 3
• However, these findings have not translated into guideline recommendations for routine aspirin use in HCM

Management Algorithm for Antithrombotic Therapy in HCM

1. Assess for AF: Screen all HCM patients for atrial fibrillation
2. If AF is present:
   • Initiate vitamin K antagonist (warfarin) with target INR 2.0-3.0 1
   • Continue lifelong anticoagulation, even when sinus rhythm is restored 1
3. If patient cannot take warfarin:
   • Consider combination therapy with aspirin 75-100 mg and clopidogrel 75 mg daily 1
   • Assess bleeding risk using HAS-BLED score 1
4. If no AF is present:
   • No routine indication for aspirin or anticoagulation

Rate and Rhythm Control in HCM with AF

In addition to anticoagulation, management of AF in HCM includes:

• Rate control: Beta-blockers and non-dihydropyridine calcium channel blockers are first-line agents 1
• Rhythm control: Amiodarone and disopyramide are potential agents for rhythm control 1, 2
• Advanced options: Catheter ablation may be considered in patients with drug-refractory symptoms 1

Pitfalls to Avoid

1. Relying on CHA₂DS₂-VASc score: This score does not adequately account for the additional thromboembolism risk in HCM 1, 2
2. Using aspirin as primary prevention: There is insufficient evidence supporting aspirin for primary prevention in HCM without AF 1
3. Underestimating AF risk: Even brief episodes of AF in HCM patients warrant anticoagulation 1, 2
4. Stopping anticoagulation after cardioversion: Lifelong anticoagulation is generally recommended even after restoration of sinus rhythm 1

In summary, aspirin plays a limited role in HCM management and should not be used as a primary therapy. For patients with HCM and AF who cannot take oral anticoagulants, aspirin may be considered as part of a combination therapy with clopidogrel, but its efficacy remains unestablished.