What is the role of beta (beta blockers) in patients with aortic stenosis?

Beta Blockers in Aortic Stenosis

Beta blockers are appropriate and safe in patients with aortic stenosis when there are compelling indications such as heart failure with reduced ejection fraction, prior myocardial infarction, arrhythmias, or angina, but should be avoided in patients with concurrent significant aortic regurgitation unless these compelling indications exist. 1, 2

Primary Guideline Recommendations

When Beta Blockers ARE Indicated in Aortic Stenosis

Beta blockers should be used in the following specific clinical scenarios:

• Heart failure with reduced ejection fraction: Provides mortality benefit even in the presence of severe aortic stenosis 2
• Post-myocardial infarction: Continue standard post-MI beta blocker therapy despite severe AS 2
• Arrhythmias: Appropriate for rate control and arrhythmia management 2
• Angina pectoris: Reduces myocardial oxygen consumption and valve gradients 2
• Coronary artery disease: May be a better choice for patients with concomitant CAD 3

When Beta Blockers Should Be AVOIDED

• Chronic aortic insufficiency/regurgitation: Beta blockers slow heart rate, which increases diastolic filling time and potentially worsens regurgitation (Class IIa recommendation, Level C evidence) 4, 1, 2
• Severe AS with moderate AR without compelling indications: Prioritize the aortic regurgitation concern in this scenario 1

Preferred First-Line Agents for Hypertension in AS

When treating hypertension in aortic stenosis without the compelling indications listed above, RAS inhibitors (ACE inhibitors or ARBs) are preferred over beta blockers. 1, 2

The advantages of RAS blockade include:

• Beneficial effects on left ventricular fibrosis 4, 2
• Improved blood pressure control 1, 2
• Reduction of dyspnea 4, 1
• Improved effort tolerance 4, 1
• Potential to retard progression of valvular stenosis 5

Treatment Approach Algorithm

Step 1: Assess for Compelling Indications

Determine if any of the following are present:

• HFrEF
• Recent MI
• Arrhythmias requiring rate control
• Angina pectoris

If YES: Beta blockers are appropriate 2

If NO: Proceed to Step 2

Step 2: Assess for Concurrent Aortic Regurgitation

• If moderate or greater AR present: Avoid beta blockers, use RAS inhibitors instead 1
• If no significant AR: Either beta blockers or RAS inhibitors acceptable, but RAS inhibitors preferred 1, 2

Step 3: Initiation and Titration

• Start at low doses and gradually titrate upward as needed 4, 2
• Target blood pressure: 130-139 mmHg systolic and 70-90 mmHg diastolic 2, 3
• Avoid lower BP targets 3

Step 4: Specialty Consultation

• Mandatory cardiology consultation or co-management for moderate-to-severe aortic stenosis, particularly when complicated by concurrent valvular lesions 4, 1, 2

Supporting Evidence for Safety

Recent observational data challenges the historical concern about beta blocker use in AS:

• The SEAS study demonstrated a 50% reduction in all-cause mortality (HR 0.5,95% CI 0.3-0.7) and 23% reduction in cardiovascular events in patients with severe AS already receiving beta blockers 2, 6
• Beta blockers did not increase risk of all-cause mortality, sudden cardiac death, or cardiovascular death in asymptomatic mild-to-moderate AS 6
• Metoprolol reduces valve gradients and myocardial oxygen consumption in asymptomatic moderate-severe AS 2

Critical Caveats

• Diuretics should be used sparingly in patients with small LV chamber dimensions and LV hypertrophy 4, 3
• Calcium channel blockers may be associated with lower survival in observational studies 3
• All current evidence is from observational studies, not randomized controlled trials 3, 5
• The combination of hypertension and aortic stenosis creates "2 resistors in series" and increases complications 4