Cardiac Drugs in Anesthesia: Perioperative Management
Beta Blockers
Beta blockers must be continued in patients already taking them chronically, particularly when prescribed for guideline-directed indications such as coronary artery disease, heart failure, or arrhythmias, as abrupt discontinuation can cause life-threatening rebound hypertension, severe angina exacerbation, myocardial infarction, and ventricular arrhythmias. 1, 2, 3, 4
Continuation Strategy for Chronic Beta Blocker Users
Continue beta blockers throughout the perioperative period in all patients currently receiving them for ACC/AHA Class I indications (coronary disease, heart failure, arrhythmias, hypertension) 1, 2
When oral administration is not possible perioperatively, use intravenous beta blockers to maintain therapy and avoid withdrawal 1
Target heart rate of 60-70 bpm throughout the perioperative period while maintaining systolic blood pressure >100 mmHg 1
The FDA explicitly warns that chronically administered beta-blocking therapy should not be routinely withdrawn prior to major surgery, though the impaired ability of the heart to respond to reflex adrenergic stimuli may augment anesthetic risks 3, 4
Initiation of Beta Blockers (Beta Blocker-Naïve Patients)
Beta blockers should NOT be started on the day of surgery in beta blocker-naïve patients, as this practice increases mortality and stroke risk. 1, 2
Starting beta blockers on the day of surgery is classified as Class III: Harm by ACC/AHA guidelines, based on the POISE trial showing increased mortality and stroke despite reduced cardiac events 1
For high-risk patients (vascular surgery with coronary disease or cardiac ischemia on testing), initiation may be considered if started 30 days to at least 2 days before surgery with careful dose titration 1
When initiating beta blockers preoperatively, use beta-1 selective agents (atenolol or bisoprolol) starting at low doses and titrating to target heart rate 1
Avoid high-dose beta blockers without titration, as fixed higher-dose extended-release metoprolol started perioperatively increases overall mortality 1
Critical Pitfalls with Beta Blockers
Never abruptly discontinue beta blockers - this causes severe exacerbation of angina, MI, ventricular arrhythmias, and rebound hypertension 1, 2, 3, 4
Do not start beta blockers in low-risk surgery patients - no benefit and potential harm 1
Avoid starting beta blockers in patients with decompensated heart failure until clinically stable 1
Respect contraindications: asthma, severe conduction disorders, symptomatic bradycardia, symptomatic hypotension 1
ACE Inhibitors and Angiotensin Receptor Blockers (ARBs)
ACE inhibitors and ARBs should be discontinued 24 hours before noncardiac surgery to reduce the risk of severe intraoperative hypotension, as recent cohort evidence demonstrates lower rates of death, stroke, myocardial injury, and hypotension with this approach. 2, 5
Preoperative Management of ACE Inhibitors/ARBs
Discontinue ACE inhibitors and ARBs 24 hours before surgery based on ACC/AHA recommendations showing improved outcomes 2, 5
This recommendation represents a shift from older practice where continuation was sometimes suggested 1
The risk of severe intraoperative hypotension with continuation creates greater morbidity risk than short-term discontinuation 5
Do not use ACE inhibitors/ARBs to control elevated blood pressure on the day of surgery - use alternative agents instead 5
Alternative Medications When ACE Inhibitors/ARBs Are Held
Continue calcium channel blockers through the day of surgery as they do not cause significant intraoperative hypotension 5
Continue beta blockers if already prescribed (see above section) 2, 5
Continue alpha-2 agonists (clonidine) to avoid rebound hypertension 2, 5
Postoperative Restart Protocol
Restart ACE inhibitors/ARBs once hemodynamically stable with adequate volume status 5
Resume as soon as oral intake is tolerated with close blood pressure monitoring 5
For patients with left ventricular systolic dysfunction, continuation under close monitoring may be considered as an individualized exception 5
Clonidine and Alpha-2 Agonists
Clonidine must be continued perioperatively as abrupt discontinuation is potentially harmful and causes severe rebound hypertension. 1, 2, 5
Continue clonidine throughout the perioperative period in all patients currently taking it 1, 2
Do not start clonidine perioperatively in patients not already taking it 6
Abrupt discontinuation carries the same risks as beta blocker withdrawal 1
Calcium Channel Blockers
Calcium channel blockers should be continued through the day of surgery as they provide blood pressure control without causing significant intraoperative hypotension. 5
Continue calcium channel blockers perioperatively - they are safe and effective 5, 7
Use caution when combining with beta blockers, particularly verapamil or diltiazem, as bradycardia and heart block can occur, especially in patients with pre-existing conduction abnormalities 4
Diuretics
Diuretics for hypertension should typically be discontinued on the day of surgery and resumed postoperatively when oral intake is possible. 2, 8
Hold diuretics for hypertension on the day of surgery to avoid hypovolemia and electrolyte disturbances 2, 8
Continue diuretics for heart failure up to the day of surgery 2
Correct electrolyte disturbances (especially hypokalemia and hypomagnesemia) before surgery in patients on diuretics 2
Blood Pressure Thresholds for Surgery
For patients with severe hypertension (≥180/110 mmHg), deferring elective major surgery should be considered until better control is achieved. 1, 2
Target blood pressure <130/80 mmHg before undertaking major elective procedures 1, 2
Assess contributing factors to perioperative hypertension: volume status, pain control, oxygenation, bladder distention 1, 2
Uncontrolled hypertension increases risk of cardiovascular disease, cerebrovascular events, and bleeding 1, 2
Intraoperative Hypertension Management
Patients with intraoperative hypertension should be managed with intravenous medications until oral medications can be resumed. 1, 2
Intravenous Antihypertensive Options
Clevidipine - safe and effective for acute hypertension in cardiac surgery, more effective than other agents without adverse events 1, 2, 5
Esmolol - short-acting beta blocker for intraoperative use 2, 5
Intraoperative Blood Pressure Dynamics
During anesthesia induction, expect 20-30 mmHg increase in BP and 15-20 bpm increase in heart rate in normotensive patients 2
In poorly controlled hypertensive patients, increases up to 90 mmHg and 40 bpm may occur 2
Patients with controlled hypertension typically respond similarly to normotensive patients 2
Maintain mean arterial pressure above 55 mmHg during surgery 1
Anti-Arrhythmic Medications
Anti-arrhythmic medications should be continued perioperatively for prevention of intraoperative and postoperative arrhythmias. 9
Continue all anti-arrhythmic medications throughout the perioperative period 9
Continuation is safe and prevents recurrence of arrhythmias 9
Special Considerations
Patients with Pheochromocytoma
Beta blockers should only be given in combination with an alpha blocker, and only after the alpha blocker has been initiated 3
Administration of beta blockers alone causes paradoxical hypertension due to unopposed alpha-mediated vasoconstriction 3
Patients with Thyrotoxicosis
Patients with Diabetes
Beta blockers may mask tachycardia of hypoglycemia but other manifestations (dizziness, sweating) remain 3, 4
Beta-1 selective agents (metoprolol, atenolol) do not delay recovery of blood glucose to normal levels 4
Patients with Bronchospastic Disease
Use beta-1 selective agents at lowest possible dose if beta blockers are necessary 3, 4
Have bronchodilators readily available 3
Consider dividing doses to avoid higher peak plasma levels 3