Pausing blood pressure meds on day of surgery benefits older adults
Pausing a patient’s usual dose of blood pressure medication on the day of surgery reduces the rate of very low blood pressure requiring treatment during the operation compared with taking their medication as normal, finds a trial of older adults, published by The BMJ today.
The researchers say this simple strategy “provides high certainty evidence supporting omission of the morning dose in this population.”
Around one third of surgical procedures worldwide involve patients aged 60 years or older, many of whom take daily blood pressure lowering drugs (antihypertensives). However, older adults are prone to low blood pressure (hypotension) during surgery, which can lead to acute kidney injury, heart attack, and death.
Some studies have shown that pausing antihypertensives 2-3 days before surgery reduces the risk of hypotension, whereas others have found no difference, and clinical guidelines provide only weak recommendations on this topic.
To address this uncertainty, researchers carried out a trial to test the effects of skipping two commonly prescribed antihypertensives - angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) - on the morning of non-cardiac surgery on rates of hypotension during surgery.
Their findings are based on 2,012 patients aged 60 to 80 years (average age 69; 54% male) with high blood pressure who had taken ACE or ARB tablets for an average of 10 years and were undergoing non-cardiac surgery under general anaesthesia at five large Chinese hospitals between November 2020 and December 2023.
Patients were randomly assigned to two groups: 1,004 continued their regular antihypertensive tablet on the morning of surgery (antihypertensive group), and 1,008 received an identical placebo tablet (no antihypertensive group).
The researchers then measured the rate of low blood pressure events during the operation, defined as mean blood pressure reading below 65 mmHg or a drop of at least 30% from before the operation, that required treatment.
The rate of hypotension during surgery was lower in the no antihypertensive group (314 out of 1,008 or 31.2%) compared with the antihypertensive group (457 out of 1,004 or 45.5%).
The duration of hypotension during surgery and need for a vasopressor (a drug to raise dangerously low blood pressure) were also reduced in the no antihypertensive group (mean difference -1.3 minutes and 28.5% vs 41.1%).
However, other measures, including postoperative hypotension, 30 day complications, and death, did not differ significantly between groups.
The researchers acknowledge that they recruited older Chinese patients having moderate length non-cardiac surgery, so findings may not apply to very high risk operations or populations in other countries. And they tracked patients only up to 30 days after surgery, so further studies are needed to assess longer term outcomes.
However, they note that trial patients had used ACE inhibitors or ARBs for an average of 10 years, and identical placebos were used to mask patients and anaesthetists, eliminating potential bias that may have affected earlier trials.
As such, they say, discontinuing ACE inhibitors or ARBs before non-cardiac surgery “should be considered whenever intraoperative hypotension is a concern, supporting the simple patient instruction to stop the morning dose on the day of surgery.”
They add: “Our findings provide high certainty evidence and will inform future international guidelines on perioperative management of these agents in older adults.”
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