Is it safe to continue losartan (angiotensin II receptor antagonist) as maintenance medication on the day of surgery for a patient with well-controlled blood pressure and no contraindications?

Losartan Should Be Discontinued 24 Hours Before Surgery

The most recent and highest quality evidence from the 2024 ACC/AHA guidelines recommends discontinuing angiotensin receptor blockers (ARBs) like losartan 24 hours before noncardiac surgery, as recent cohort data demonstrates lower rates of death, stroke, myocardial injury, and intraoperative hypotension compared to continuing these medications until surgery. 1

Evidence-Based Rationale

Why ARBs Should Be Held

The 2024 ACC/AHA guidelines explicitly state that angiotensin-receptor blockers have been associated with increased risk of intraoperative hypotension when continued perioperatively 2. This represents a shift from older guidance that suggested continuation of most antihypertensives.

Discontinuation of ACE inhibitors or ARBs perioperatively may be considered to reduce the risk of intraoperative hypotension, according to the most recent American Heart Association recommendations 3. The American College of Cardiology reinforces that it is reasonable to continue other antihypertensive medications until the day of surgery, except for ACE inhibitors or ARBs 3.

Supporting Research Evidence

A prospective randomized study demonstrated that patients chronically treated with angiotensin II antagonists who received their medication on the morning of surgery experienced significantly more frequent episodes of hypotension (2±1 vs 1±1 episodes), longer duration of hypotension (8±7 min vs 3±4 min), and increased need for vasoactive drugs compared to those who discontinued the medication 24 hours prior 4.

Management Algorithm for the Day of Surgery

Step 1: Discontinue Losartan 24 Hours Preoperatively

• Hold losartan the day before surgery to minimize intraoperative hypotension risk 1, 4
• This applies even if blood pressure is elevated on the morning of surgery 1

Step 2: Continue Other Antihypertensives

• Beta blockers MUST be continued if the patient is already taking them chronically to avoid rebound hypertension 3, 1
• Calcium channel blockers should be continued through the day of surgery as they do not cause significant intraoperative hypotension 1
• Alpha-2 agonists (clonidine) must be continued to avoid rebound hypertension 3, 1

Step 3: Blood Pressure Threshold Assessment

• If blood pressure is ≥180/110 mmHg, consider deferring elective major surgery until better control is achieved 3, 1
• Target blood pressure <130/80 mmHg is reasonable before major elective procedures, achieved with medications other than ARBs 1

Step 4: Intraoperative Management

• If hypertension develops intraoperatively after ARBs have been held, use IV antihypertensive agents such as clevidipine, esmolol, or nicardipine until oral medications can be resumed postoperatively 3, 1
• Maintain intraoperative MAP ≥60-65 mmHg or SBP ≥90 mmHg to reduce risk of myocardial injury 2

Step 5: Postoperative Restart

• Restart losartan once the patient is hemodynamically stable and volume status is adequate 1
• Resume ARBs as soon as clinically feasible when oral intake is tolerated 1
• The 2024 guidelines recommend that preoperative antihypertensive medications be restarted as soon as clinically reasonable to avoid complications from postoperative hypertension 2

Critical Pitfalls to Avoid

Do NOT Continue Losartan on Surgery Day

Do not continue ARBs on the day of surgery even with elevated blood pressure, as the risk of severe intraoperative hypotension creates greater morbidity risk than short-term hypertension 1. The decision is drug class-specific, and ARBs fall into the category requiring discontinuation 2.

Do NOT Abruptly Stop Beta Blockers or Clonidine

Abrupt preoperative discontinuation of beta blockers or clonidine is potentially harmful due to risk of rebound hypertension 3. This creates a more dangerous situation than the controlled discontinuation of ARBs 1.

Do NOT Start New Beta Blockers

Beta blockers should NOT be started on the day of surgery in beta blocker-naïve patients due to increased risk of harm 3.

Special Considerations

High-Risk Populations Requiring Extra Caution

Caution is advised when continuing antihypertensive therapy in patients with low or low-normal perioperative blood pressures, older adults (≥65 years), and patients in whom the risk for perioperative hypotension is high based on overall clinical status, surgery type, and anesthetic plan 2.

Exception for Left Ventricular Dysfunction

For patients with left ventricular systolic dysfunction, there is nuanced guidance suggesting ARBs may be continued under close monitoring, but this represents a specific exception requiring individualized hemodynamic monitoring rather than routine practice 1.