What is the recommended beta blocker (beta-adrenergic blocking agent) therapy for an older patient with abdominal aortic aneurysm (AAA) and significant cardiovascular disease burden?

Beta Blocker Therapy for Abdominal Aortic Aneurysm

Beta blockers may be considered for patients with AAA to potentially reduce aneurysm expansion rates, though the evidence for this indication is weak (Class IIb recommendation); however, they are strongly indicated perioperatively in AAA patients with coronary artery disease to reduce cardiac events and mortality. 1

Clinical Context and Evidence Quality

The role of beta blockers in AAA management differs substantially from their use in thoracic aortic aneurysms, where evidence is stronger. For AAA specifically:

Medical Management for Aneurysm Growth

• Beta blockers may be considered to reduce the rate of aneurysm expansion in patients with aortic aneurysms (Class IIb, Level B), representing uncertain benefit based on limited evidence. 1

• A 2021 meta-analysis of eight clinical trials found beta blockers showed no statistically significant effect on AAA growth rates (standard mean difference -0.44; 95% CI [-0.44,0.00]), indicating the evidence does not support their routine use for slowing aneurysm expansion. 2

• Earlier studies suggested propranolol might slow AAA progression through mechanisms including lysyl-oxidase stimulation and elastin bridge production, but these findings have not translated into robust clinical benefit. 3, 4

Perioperative Cardiac Protection (Strong Indication)

• Perioperative administration of beta-adrenergic blocking agents is indicated (Class I, Level A) to reduce the risk of adverse cardiac events and mortality in patients with coronary artery disease undergoing surgical repair of atherosclerotic aortic aneurysms. 1

• This represents the strongest evidence-based indication for beta blockers in the AAA population, given the significant cardiovascular disease burden in these patients. 1

Blood Pressure Management Strategy

Target Blood Pressure Goals

• Achieve systolic BP <130 mm Hg and diastolic BP <80 mm Hg to reduce cardiovascular events including myocardial infarction, stroke, and potentially aneurysm rupture. 5, 6

• In select AAA patients without diabetes who are not undergoing surgical repair, intensive SBP control to <120 mm Hg may provide additional benefit if tolerated, based on SPRINT trial data showing 25% reduction in cardiovascular events and 27% reduction in all-cause mortality. 6

Choice of Antihypertensive Agent

For AAA patients requiring blood pressure control, the choice between beta blockers and RAAS inhibitors (ACE inhibitors/ARBs) should favor RAAS inhibitors based on recent outcomes data:

• A 2023 Medicare-linked database study of 8,789 AAA patients found RAAS inhibitors were associated with superior outcomes compared to beta blockers, including lower postoperative mortality (OR 0.3), lower myocardial infarction rates (OR 0.1), lower 1-year mortality (HR 0.4), and reduced aneurysmal rupture risk (HR 0.7). 7

• This represents the most recent and highest quality comparative evidence for medical management of AAA patients with hypertension. 7

• ACE inhibitors or ARBs may be considered in all patients with peripheral arterial disease, including aortic aneurysms, regardless of blood pressure levels, in the absence of contraindications. 6

Practical Algorithm for Beta Blocker Use in AAA

Use beta blockers in AAA patients when:

1. Perioperative period (if coronary artery disease present) - Class I indication 1
2. Established cardiac indications (heart failure, post-MI, atrial fibrillation) - use per cardiac guidelines 5
3. Second-line for hypertension if RAAS inhibitors are contraindicated or insufficient as monotherapy 5, 6

Avoid relying on beta blockers as primary therapy for:

• Slowing AAA growth rates (insufficient evidence) 2
• First-line hypertension management in AAA (RAAS inhibitors preferred) 7

Critical Caveats

• Combination therapy is usually required to achieve target blood pressure goals; beta blockers should be combined with ACE inhibitors or ARBs for optimal control when both are needed. 6

• Uncontrolled hypertension remains a known risk factor for aortic rupture and dissection; aggressive blood pressure control is essential even in asymptomatic patients. 6

• The 2022 ACC/AHA guidelines note that outcomes data from clinical trials of medical therapy in aortic aneurysms are broadly limited, with most trials focused on genetic aortopathies rather than degenerative AAA. 1

• Beta blockers have not been shown to modify AAA growth rates in clinical trials, though dropout rates have been high in these studies. 4