Beta Blockers to Prevent Perioperative MI

OVERVIEW

• The use of Beta-blockers in perioperative medicine has been an issue of intense research in Anaesthesia.
• Patients that are believed to benefit from beta-blockers are those with risk factors for ischaemic heart disease (HT, DM, hypercholesterolaemia, previous MI, angina, controlled heart failure)
• There are arguments for and against their use.

Benefits

• lowering of heart rate
• decreased Q
• decreased afterload
• decreased myocardial oxygen consumption
• prevention of perioperative tachycardia and subsequent non-ST elevation myocardial infarction
• prevention of arrhythmia (atrial fibrillation)
• decrease in bleeding

Disadvantages

• a significant increase in episodes of perioperative hypotension
• sympathetic blockade decreasing response to hypovolaemia (tachycardia and increase in cardiac output)
• a significant increase in perioperative cerebrovascular events
• increased risk of bradycardia
• a significant increase morbidity and mortality

-> a number of these adverse effects have been documented via a recent trial entitled the POISE trial

An approach:

• if a patient is already taking beta-blockers for an established medical problem then I continue throughout the perioperative period
• I do not start my patients on beta-blockers perioperatively based on information obtained from the POISE trial
• if a patient is seen preoperatively and may benefit from beta blockade, has at least 1 week prior to their surgery I would consider starting an agent if there were no contraindications (as per DECREASE trial protocol)

References and Links

• Graber MA, Dachs RJ, Darby-Stewart A. Beta blockers and noncardiac surgery: why the POISE study alone should not change your practice.Am Fam Physician. 2010 Mar 15;81(6):717. PMID: 20229970 [Fulltext]
• POISE Study Group, Devereaux PJ, et al. Effects of extended-release metoprolol succinate in patients undergoing non-cardiac surgery (POISE trial): a randomised controlled trial. Lancet. 2008 May 31;371(9627):1839-47. Epub 2008 May 12. PMID: 18479744
• Poldermans D, Boersma E, Bax JJ, et al. The effect of bisoprolol on perioperative mortality and myocardial infarction in high-risk patients undergoing vascular surgery. Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echocardiography Study Group. N Engl J Med. 1999;341(24):1789–1794. PMID: 10588963 [Fulltext]