How should antihypertensive medications be managed in a patient with hypertension who is undergoing surgery, considering the risk of bleeding and blood pressure control?

Perioperative Antihypertensive Management: Balancing Bleeding Risk and Blood Pressure Control

In most patients with hypertension undergoing surgery, continue antihypertensive medications throughout the perioperative period, with the critical exception of ACE inhibitors and ARBs, which should be discontinued 24 hours before surgery to prevent severe intraoperative hypotension while minimizing bleeding risk from uncontrolled hypertension. 1, 2

Preoperative Medication Management Algorithm

Medications to CONTINUE Until Surgery

• Beta blockers MUST be continued in patients already taking them chronically to prevent rebound hypertension, which increases risk for myocardial ischemia, acute heart failure, and dysrhythmias 1, 3, 4
• Calcium channel blockers should be continued through the day of surgery as they maintain blood pressure control without causing significant intraoperative hypotension 3, 2
• Clonidine (alpha-2 agonists) MUST be continued to avoid dangerous rebound hypertension 1, 2, 4
• Abrupt discontinuation of beta blockers or clonidine is potentially harmful and creates greater morbidity risk than controlled medication management 1

Medications to HOLD Before Surgery

• ACE inhibitors and ARBs should be discontinued 24 hours before noncardiac surgery based on recent cohort evidence demonstrating lower rates of death, stroke, myocardial injury, and intraoperative hypotension compared to continuing these medications 2, 4
• This recommendation represents an evolution from older guidelines that were more equivocal about ACE inhibitor/ARB management 1
• The risk of severe intraoperative hypotension from continuing ACE inhibitors/ARBs creates greater morbidity than short-term hypertension 2

Blood Pressure Thresholds for Surgery

When to Defer Elective Surgery

• Consider deferring elective major surgery if SBP ≥180 mm Hg or DBP ≥110 mm Hg before the day of surgery in patients with cardiovascular risk factors 1, 2
• This deferral reduces risk of perioperative complications including cardiovascular events, cerebrovascular events, and bleeding 1

Target Blood Pressure Goals

• Preoperatively, target BP <130/80 mm Hg is reasonable before undertaking major elective procedures, achieved with medications other than ACE inhibitors/ARBs in the immediate preoperative period 1, 2

Intraoperative Blood Pressure Management

Critical Hemodynamic Targets

• Maintain intraoperative MAP ≥60-65 mm Hg or SBP ≥90 mm Hg to reduce risk of myocardial injury, acute kidney injury, and mortality 1, 3, 4
• Intraoperative hypotension (MAP <65 mm Hg or SBP <90 mm Hg for >15 minutes) is associated with postoperative myocardial injury, acute kidney injury, and mortality 3
• Higher blood pressure targets may be appropriate for older adults (≥65 years) or patients with chronic hypertension to maintain organ perfusion 1, 4

Intravenous Antihypertensive Agents

• Use IV medications with rapid onset, short duration, and easy titratability when hypertension develops intraoperatively after ACE inhibitors/ARBs have been held 3, 4
• Recommended agents include clevidipine, nicardipine, esmolol, and labetalol until oral medications can be resumed 1, 2, 4
• Clevidipine may be more effective than other agents based on meta-analysis showing safe and effective treatment without adverse events 1, 4
• Nicardipine has a mean time to therapeutic response of 12 minutes 4

Postoperative Blood Pressure Management

Immediate Assessment Priorities

• Evaluate and address reversible causes before initiating pharmacologic therapy: pain control, volume status (both hypovolemia and hypervolemia), oxygenation, and bladder distention 1, 4
• Bladder distention can cause reflex hypertension 4

Medication Resumption Protocol

• Restart preoperative antihypertensive medications as soon as clinically reasonable to avoid complications from postoperative hypertension 1
• Delaying resumption of antihypertensive medications is associated with increased 30-day mortality risk 3, 4
• Resume ACE inhibitors/ARBs once the patient is hemodynamically stable and volume status is adequate, monitoring blood pressure closely after restarting 2, 4

Postoperative Hypotension Management

• Treatment of hypotension (MAP <60-65 or SBP <90 mm Hg) in the postoperative period is recommended to limit risk of cardiovascular, cerebrovascular, renal events, and mortality 1

Critical Pitfalls to Avoid

• NEVER start beta blockers on the day of surgery in beta blocker-naïve patients - this is potentially harmful 1, 4
• NEVER continue ACE inhibitors/ARBs on the day of surgery even with elevated blood pressure - the risk of severe intraoperative hypotension creates greater morbidity than short-term hypertension 2
• NEVER abruptly stop beta blockers or clonidine - rebound hypertension is more dangerous than controlled discontinuation of ACE inhibitors/ARBs 1, 2
• Exercise caution when continuing antihypertensive therapy in older adults (≥65 years) and patients at high risk for perioperative hypotension 1

Relationship Between Hypertension and Bleeding Risk

Perioperative hypertension increases the risk of bleeding in addition to cardiovascular and cerebrovascular events 1. This creates a critical balance: uncontrolled hypertension increases bleeding risk, but overly aggressive blood pressure reduction (particularly with ACE inhibitors/ARBs continued perioperatively) causes profound hypotension that increases mortality and morbidity. The recommended approach prioritizes maintaining adequate perfusion pressure (MAP ≥60-65 mm Hg) while avoiding severe hypertension (SBP ≥180 mm Hg) that increases bleeding risk 1.