Globally, about 100 million adults have non-cardiac surgery (ie. on any part of the body other than the heart) each year. Around 1% are at risk of cardiac complications, such as heart attacks and strokes, and about one in four will die each year.
Two types of drugs - ß blockers and statins - are regularly given to patients to prevent such complications. They are given shortly before, during, or after surgery (the perioperative stage) to help lower blood pressure.
But doctors in Australia now warn that the benefit of using these drugs at this time remains unclear.
They cite several large international studies that found no benefit from perioperative ß blockers.
Two studies from Denmark and the UK reported no reduction in death or several other serious complications, such as heart attack, heart failure, and stroke 30 days after surgery in patients receiving ß blockers. Another study found no benefit six months after surgery, and a trial currently underway has so far not reported any beneficial effects.
However, all studies did report significantly higher rates of important side effects with ß blockers, including slow heart beat (bradycardia) and very low blood pressure (hypotension). This has led to calls to examine the widespread use of perioperative ß blocking drugs.
Like ß blockers, statins have also been advocated to reduce the risk of perioperative cardiac complications, write the authors. Non-randomised trials suggest that statins confer benefit, but the evidence remains weak, and to prove a strong overall survival benefit would require a 'gold-standard' randomised controlled trial of more than 12,000 patients.
The benefits of statins in reducing cardiac complications in the general population and high risk patients are well known, but robust evidence to confirm that these drugs are valuable in routine perioperative use has not been published, they say.
So, on the basis of the evidence currently available, what should practising clinicians do? They suggest that patients already receiving ß blockers or statins before surgery should continue with treatment. But no patient should start taking statins or ß blockers in the perioperative period specifically to reduce the likelihood of perioperative cardiac events.