What are the recent American Heart Association (AHA) guidelines for using beta (beta blockers) blockers in patients undergoing cardiac surgery?

Recent AHA Guidelines for Beta Blockers in Cardiac Surgery

Beta blockers should be continued in patients undergoing cardiac surgery who are receiving beta blockers for treatment of conditions with ACCF/AHA Class I guideline indications such as angina, symptomatic arrhythmias, or hypertension. 1

General Recommendations for Beta Blocker Use in Cardiac Surgery

Class I Recommendations (Strong)

• Beta blockers should be continued without interruption in patients already taking them for approved indications such as angina, symptomatic arrhythmias, or hypertension 1
• Beta blockers should be given to patients undergoing vascular surgery who are at high cardiac risk due to the presence of more than one clinical risk factor 1
• Chronically administered beta-blocker therapy should not be routinely withdrawn prior to major surgery, as this may increase risk of cardiac events 2

Class IIa Recommendations (Reasonable)

• Beta blockers titrated to heart rate and blood pressure are reasonable for patients undergoing vascular surgery who are at high cardiac risk due to coronary artery disease or cardiac ischemia on preoperative testing 1
• Beta blockers are reasonable for patients undergoing vascular surgery in whom preoperative assessment identifies high cardiac risk (more than one clinical risk factor) 1
• Beta blockers are reasonable for patients with coronary heart disease or high cardiac risk undergoing intermediate-risk surgery 1

Class IIb Recommendations (May Consider)

• The usefulness of beta blockers is uncertain for patients undergoing intermediate-risk procedures or vascular surgery with a single clinical risk factor 1
• The usefulness of beta blockers is uncertain in patients undergoing vascular surgery with no clinical risk factors who are not currently taking beta blockers 1

Class III Recommendations (Not Recommended)

• Beta blockers should not be given to patients undergoing surgery who have absolute contraindications to beta blockade 1

Special Considerations for Beta Blocker Use

Dosing and Titration

• Beta blockers should be titrated to heart rate and blood pressure rather than using fixed higher doses without titration 1
• When initiating beta blockers preoperatively, start at a low dose and gradually titrate up to avoid adverse effects 1
• Longer-acting beta blockers appear superior to shorter-acting agents for perioperative use 1

Timing of Administration

• For patients already on beta blockers, continue therapy throughout the perioperative period 1, 3
• For patients requiring new initiation of beta blockers, ideally start therapy well before surgery to allow for proper dose titration 1

Patient Selection

• Use caution when applying recommendations on beta-blocker therapy to patients with:
  • Decompensated heart failure 1, 2
  • Nonischemic cardiomyopathy 1
  • Severe valvular heart disease in the absence of coronary heart disease 1
• Beta blockers may be beneficial in patients with left ventricular systolic dysfunction, but should be initiated at very low doses with careful titration 4

Contraindications

• Absolute contraindications to beta blocker use include:
  • Severe bradycardia or heart block without a pacemaker 2
  • Decompensated heart failure 2
  • Severe hypotension 2, 5
• Use beta blockers with caution in patients with bronchospastic disease, though cardioselective agents may be considered at the lowest effective dose 2, 6

Beta Blocker Selection

• Carvedilol appears to be superior to metoprolol for prevention of postoperative atrial fibrillation in some studies 7
• Cardioselective beta blockers (like metoprolol) may be preferable in patients with relative contraindications such as mild to moderate reactive airway disease 6
• Beta blockers with additional vasodilating properties (carvedilol) may be beneficial in patients with heart failure 4

Common Pitfalls and Caveats

• Avoid abrupt discontinuation of beta blockers in the perioperative period, which can lead to rebound hypertension, tachycardia, and increased risk of myocardial ischemia 2, 3
• Routine administration of high-dose beta blockers without proper titration may increase risk of stroke and mortality in beta-blocker-naïve patients 1
• Beta blockers may mask signs of hypoglycemia (particularly tachycardia) in diabetic patients 2, 5
• Monitor for bradycardia and hypotension, especially during anesthesia induction 2
• Beta blockers should not be discontinued prior to surgery but may require dose adjustment based on hemodynamic parameters 1, 2