How to manage preoperative uncontrolled hypertension (HTN) in patients undergoing elective surgery?

Management of Preoperative Uncontrolled Hypertension in Elective Surgery

Elective surgery should be postponed when blood pressure is ≥180/110 mmHg, with patients referred back to their primary care physician for evaluation and treatment before proceeding with surgery. 1

Blood Pressure Thresholds for Surgical Decision-Making

The management of preoperative hypertension follows clear thresholds based on current guidelines:

• BP <160/100 mmHg: Proceed with elective surgery 2
• BP 160/100-179/109 mmHg: Proceed with surgery, but inform primary care physician 2, 1
• BP ≥180/110 mmHg: Postpone elective surgery and refer to primary care for management 2, 1

This algorithm is supported by the Association of Anaesthetists of Great Britain and Ireland, British Hypertension Society, American Heart Association, and American College of Cardiology guidelines.

Preoperative Assessment Protocol

1. Document BP history:

   • Review BP measurements from the past 12 months
   • If not documented, measure BP during preoperative consultation
   • Take up to three measurements if initial reading is elevated 2

2. Risk stratification:

   • Assess for target organ damage (more important than BP alone)
   • Evaluate overall cardiovascular risk factors 2, 3

3. Communication with primary care:

   • When elevated BP is detected, inform the patient's GP
   • Provide clear instructions for follow-up and pathway to re-establish surgical scheduling 2

Antihypertensive Treatment Approach

For patients requiring BP control before surgery, follow this stepwise approach:

Step 1 Treatment

• Patients <55 years: ACE inhibitor or ARB
• Patients ≥55 years or Black patients: Calcium channel blocker (CCB)
• If CCB not suitable (edema, intolerance) or heart failure present: Thiazide-like diuretic 2, 1

Step 2 Treatment

• Combine ACE inhibitor/ARB with CCB
• If CCB unsuitable: Use thiazide-like diuretic 2

Step 3 Treatment

• Triple therapy: ACE inhibitor/ARB + CCB + thiazide-like diuretic 2

Step 4 Treatment

• Add spironolactone, alpha-blocker, or beta-blocker 1

Perioperative Medication Management

• Continue most antihypertensive medications throughout the perioperative period 2, 1
• Never abruptly discontinue beta-blockers or clonidine preoperatively due to risk of rebound hypertension 1, 4
• Consider temporarily suspending ACE inhibitors/ARBs perioperatively to reduce risk of intraoperative hypotension 1
• Resume antihypertensive medications as soon as clinically reasonable postoperatively 2

Intraoperative Management

• Maintain MAP ≥60-65 mmHg or SBP ≥90 mmHg during surgery to reduce risk of myocardial injury 2
• Continuous BP monitoring is essential before, during, and after the procedure 1
• Be prepared for labile hemodynamics in hypertensive patients during anesthesia 1

Postoperative Care

• Treat postoperative hypotension (MAP <60-65 or SBP <90 mm Hg) to limit cardiovascular, cerebrovascular, and renal events 2
• Provide adequate analgesia to avoid excessive BP fluctuations 1
• Resume oral antihypertensive medications as soon as possible 2

Common Pitfalls to Avoid

1. Unnecessary postponement: Don't delay surgery for BP <180/110 mmHg, as this increases risks from delayed treatment and aging 2

2. Acute BP reduction in OR: Rapid reduction of BP immediately before surgery can lead to hemodynamic instability 5

3. Overlooking medication interactions: Some anesthetics may interact with antihypertensive medications, particularly with calcium channel blockers and beta-blockers 4

4. Focusing only on BP numbers: Target organ damage and overall cardiovascular risk are more important predictors of perioperative complications than BP alone 3

5. Inadequate postoperative monitoring: Hypertensive patients require vigilant BP monitoring postoperatively to prevent complications 6