Are beta‑blockers safe or appropriate for patients with pulmonary hypertension, and when can they be used?

Beta-Blockers in Pulmonary Hypertension: Safety and Clinical Use

Beta-blockers are generally not recommended in pulmonary arterial hypertension (PAH) and should be avoided unless there is a compelling cardiac indication such as coronary artery disease or heart failure, as they can worsen exercise capacity and hemodynamics without improving right ventricular function.

Evidence Against Routine Use in PAH

The most recent and highest-quality evidence demonstrates significant concerns with beta-blocker use specifically in pulmonary hypertension:

• In portopulmonary hypertension, beta-blockers cause demonstrable harm: A prospective study showed that beta-blocker withdrawal resulted in a 79-meter improvement in 6-minute walk distance (p=0.01), a 28% increase in cardiac output (p<0.01), and a 19% decrease in pulmonary vascular resistance (p<0.01). The improvements were directly related to restoration of chronotropic response, which increased from 18 to 34 beats/min during exercise (p<0.01). 1

• In idiopathic PAH, bisoprolol showed no benefit and potential harm: A randomized, placebo-controlled crossover trial in stable idiopathic PAH patients found that while bisoprolol successfully reduced heart rate by 17 beats/min (p=0.0001), it caused a significant drop in cardiac index (0.5 L·min⁻¹·m⁻² decrease, p=0.015) and a trend toward decreased 6-minute walking distance, with no improvement in right ventricular ejection fraction. 2

When Beta-Blockers May Be Considered

Beta-blockers should only be used in PAH patients when there is a specific cardiac comorbidity requiring their use, such as:

• Post-myocardial infarction: Beta-blockers reduce mortality by approximately 13% in acute coronary syndromes and remain indicated for secondary prevention. 3

• Heart failure with reduced ejection fraction: Bisoprolol, metoprolol succinate, and carvedilol are preferred agents with proven mortality benefit. 3

• Coronary artery disease with angina: Beta-blockers remain first-line for angina management. 3

Safety Data in PAH Populations

Observational studies provide reassurance that beta-blockers are not absolutely contraindicated when needed for cardiac comorbidities:

• Propensity-matched analyses show neutral mortality effects: Two large registry studies found no statistically significant increase in all-cause mortality with beta-blocker use in PAH patients (adjusted HR 1.0-1.2), though these patients were carefully selected with cardiac indications. 4, 5

• Functional outcomes remain concerning: Even in observational studies showing neutral mortality, patients on beta-blockers consistently walked shorter distances on 6-minute walk tests, suggesting impaired functional capacity. 4, 6

Clinical Algorithm for Decision-Making

Step 1: Assess the indication

• Is there a compelling cardiac indication (post-MI, HFrEF, symptomatic coronary disease)? If NO → Do not use beta-blockers. 3

Step 2: If cardiac indication exists, assess PAH severity

• Is the patient in WHO functional class IV or hemodynamically unstable? If YES → Defer beta-blocker initiation until stabilized. 2
• Is there portopulmonary hypertension? If YES → Beta-blockers are contraindicated due to proven harm. 1

Step 3: Select appropriate agent if proceeding

• Use cardioselective beta-1 blockers (bisoprolol, metoprolol succinate) rather than non-selective agents. 3
• For heart failure: bisoprolol, metoprolol succinate, or carvedilol are preferred. 3

Step 4: Initiate at lowest dose with close monitoring

• Start at 25-50% of target dose. 3
• Monitor for: worsening dyspnea, decreased exercise tolerance, signs of right heart failure, excessive bradycardia. 2, 1
• Measure 6-minute walk distance before and 4-6 weeks after initiation. 2

Step 5: Avoid in specific contraindications

• Severe bradycardia (HR <50 bpm), second- or third-degree AV block without pacemaker, decompensated right heart failure, or systolic BP <90 mmHg. 3

Key Pitfalls to Avoid

• Do not use beta-blockers for rate control alone in PAH: The reduction in heart rate impairs the compensatory tachycardia needed to maintain cardiac output in the setting of fixed pulmonary vascular resistance. 1

• Do not assume all beta-blockers are equivalent: Cardioselective agents are preferred over non-selective agents, and agents with proven mortality benefit in heart failure (bisoprolol, metoprolol succinate, carvedilol) should be chosen when treating HFrEF. 3

• Do not ignore functional decline: Even if hemodynamics appear stable, worsening exercise capacity is clinically significant and may warrant dose reduction or discontinuation. 2, 4

Guideline Recommendations

Current hypertension guidelines list beta-blockers as appropriate antihypertensive agents but specifically note they are not recommended as first-line agents unless the patient has ischemic heart disease or heart failure. 3 The 2016 ESC/ERS guidelines for pulmonary hypertension do not recommend beta-blockers as part of PAH-specific therapy. 3

The 2019 CHEST guidelines for PAH therapy focus on PAH-specific medications (prostacyclins, endothelin antagonists, phosphodiesterase inhibitors, soluble guanylate cyclase stimulators) and do not include beta-blockers in treatment algorithms. 3