Which antihypertensives, such as Angiotensin-Converting Enzyme (ACE) inhibitors and Angiotensin II Receptor Blockers (ARBs), should be withheld prior to surgery to avoid hypotension?

Perioperative Management of Antihypertensive Medications

ACE inhibitors and ARBs should be discontinued 24 hours before major surgery, while beta blockers and most other antihypertensives should be continued through the perioperative period. 1

Specific Recommendations by Medication Class

Medications to Withhold:

• ACE inhibitors and ARBs
  • Discontinue 24 hours before surgery 1
  • Rationale: Significantly increases risk of intraoperative hypotension 2, 3
  • Class IIb recommendation, Level B-NR evidence 1
  • May be resumed postoperatively once patient is euvolemic 1

Medications to Continue:

• Beta blockers

  • Continue through the perioperative period 1
  • Class I recommendation, Level B-NR evidence 1
  • Abrupt discontinuation can cause rebound hypertension and tachycardia 1
  • WARNING: Never start beta blockers on the day of surgery in beta blocker-naïve patients (Class III: Harm) 1

• Calcium channel blockers

  • Continue through the perioperative period 4
  • Particularly useful for managing perioperative hypertension 1

• Alpha-2 agonists (e.g., clonidine)

  • Continue through the perioperative period 1
  • Abrupt discontinuation can cause dangerous rebound hypertension 1
  • WARNING: Do not initiate alpha-2 agonists perioperatively (Class III recommendation) 1

• Diuretics

  • Generally continued, but may be held on the morning of surgery if concerns about volume status 4
  • Monitor electrolytes and volume status carefully

Special Considerations

Timing of Medication Administration:

• For medications being continued, administer on the morning of surgery with a small sip of water 4
• For ACE inhibitors/ARBs being withheld, last dose should be >24 hours before surgery 3

Blood Pressure Thresholds for Surgery:

• Consider postponing elective surgery if:
  • Systolic BP ≥180 mmHg or
  • Diastolic BP ≥110 mmHg 1, 4
  • Class IIb recommendation, Level C-LD evidence 1

Intraoperative Management:

• Patients on chronic antihypertensive therapy are more prone to intraoperative hypotension 5
• Those continuing ACE inhibitors/ARBs have higher risk of hypotension requiring vasopressors 2, 3
• Maintain mean arterial pressure ≥60-65 mmHg or systolic BP ≥90 mmHg 4

Postoperative Considerations:

• Resume antihypertensive medications as soon as clinically reasonable 4
• Restart ACE inhibitors/ARBs only after confirming euvolemic status 1
• Treat postoperative hypertension promptly to reduce complications 4

Common Pitfalls to Avoid

1. Abrupt discontinuation of beta blockers or clonidine can cause dangerous rebound hypertension and is potentially harmful (Class III: Harm) 1

2. Starting beta blockers on the day of surgery in beta blocker-naïve patients increases mortality risk (Class III: Harm) 1

3. Continuing ACE inhibitors/ARBs through surgery increases risk of significant intraoperative hypotension that may be refractory to vasopressors 2, 3

4. Failing to restart antihypertensive medications postoperatively can increase 30-day mortality 4

5. Overlooking reversible causes of postoperative hypertension (pain, anxiety, urinary retention, hypoxemia) before administering additional antihypertensives 4

By following these evidence-based recommendations for perioperative antihypertensive management, you can minimize the risks of both intraoperative hypotension and postoperative hypertensive complications, ultimately improving patient outcomes.