What are the recommendations for managing angiotensin receptor blockers (ARBs) in patients undergoing surgery and anesthesia?

Perioperative Management of Angiotensin Receptor Blockers (ARBs)

Discontinuation of ARBs 24 hours before major surgery may be considered to reduce the risk of intraoperative hypotension, though this remains a Class IIb recommendation with moderate-quality evidence. 1

Key Recommendations

Preoperative Management

• ARB discontinuation is optional (Class IIb): The 2017 ACC/AHA guidelines state that discontinuation of ARBs perioperatively may be considered in patients undergoing major surgery, reflecting the controversial nature of this decision. 1

• Timing of discontinuation: If you choose to hold ARBs, discontinue them 24 hours before surgery to minimize intraoperative hypotension risk. 2

• Continue other antihypertensives: It is reasonable to continue most other antihypertensive medications until surgery, with specific attention to beta-blockers (which should absolutely be continued if chronically used) and calcium channel blockers (which can generally be continued safely). 1

The Evidence Behind ARB Discontinuation

The controversy exists because:

• Increased hypotension risk: Patients continuing ARBs have a 41% increased risk of intraoperative hypotension (RR 1.41,95% CI: 1.21-1.64) compared to those who discontinue. 3

• No difference in hard outcomes: Despite increased hypotension, there are no significant differences in postoperative complications including myocardial infarction, stroke, acute kidney injury, or death between continuation and discontinuation groups. 3

• Recent cohort data supports discontinuation: A large cohort study demonstrated that patients who stopped ARBs 24 hours before noncardiac surgery had better composite outcomes and less intraoperative hypotension than those continuing medications. 2

• Hypotension is manageable: When hypotension occurs, it typically responds to standard vasopressor therapy (ephedrine, phenylephrine, or terlipressin) without adverse clinical consequences. 4, 5

Intraoperative Management

• Anticipate hypotension: If ARBs are continued, anesthesiologists should be prepared for more frequent and prolonged hypotensive episodes requiring vasopressor support. 4

• Treat hypotension aggressively: Use IV medications (ephedrine, phenylephrine, or terlipressin) to maintain systolic blood pressure within 30% of baseline values. 4

• Address contributing factors: Before treating with vasopressors, assess volume status, pain control, oxygenation, and bladder distention. 1

Postoperative Management

• Restart ARBs promptly: If ARBs were held preoperatively, restart them as soon as clinically feasible postoperatively when the patient is hemodynamically stable and volume status is adequate. 1, 2

• Monitor closely: Ensure blood pressure is monitored carefully after restarting ARBs to prevent postoperative hypotension. 2

• Use IV agents if needed: For patients with intraoperative hypertension who cannot take oral medications, manage with IV antihypertensives until oral medications can be resumed. 1

Special Considerations

Patients with Left Ventricular Dysfunction

• Consider continuation: For patients with left ventricular systolic dysfunction, continuing ARBs perioperatively under close hemodynamic monitoring may be beneficial given their cardioprotective effects. 2

Severely Elevated Blood Pressure

• Consider deferring surgery: In patients with planned elective major surgery and SBP ≥180 mmHg or DBP ≥110 mmHg, deferring surgery may be considered until better blood pressure control is achieved. 1

Ambulatory Surgery

• Discontinuation may not increase rebound hypertension: Evidence from ambulatory surgery patients shows that discontinuing ACE inhibitors/ARBs on the day of surgery does not result in substantively increased incidence of pre- or postoperative hypertension. 6

Clinical Pitfalls to Avoid

• Do not confuse with beta-blockers: Unlike ARBs, beta-blockers should absolutely be continued in patients chronically receiving them (Class I recommendation), as abrupt discontinuation is potentially harmful. 1

• Do not start new ARBs perioperatively: This recommendation applies only to patients chronically taking ARBs, not to initiating new therapy in the perioperative period. 1

• Do not assume all antihypertensives behave similarly: Calcium channel blockers, unlike ARBs, do not typically cause significant intraoperative hypotension warranting discontinuation and can generally be continued. 2

Practical Algorithm

For patients on chronic ARBs undergoing major surgery:

1. Assess surgical urgency and patient risk factors (left ventricular dysfunction, severity of hypertension). 2

2. For most patients: Consider holding ARBs 24 hours before surgery to reduce hypotension risk, recognizing this will not affect hard outcomes. 2, 3

3. For patients with LV dysfunction: Consider continuing ARBs with close monitoring given cardioprotective benefits. 2

4. Communicate with anesthesia team: Ensure they are aware of ARB use and prepared to manage hypotension. 4

5. Restart postoperatively: Resume ARBs once hemodynamically stable with adequate volume status. 1, 2