Experts have identified a link between the circadian clock – the internal body clock that controls when we sleep, eat and wake up – and damage after surgery.
Following open heart surgery, some patients developed damage impacting on the organ’s ability to pump blood, resulting in heart failure and a heightened risk of death.
Professor David Montaigne, of the University of Lille in France, said: “Currently, there are few other surgical options to reduce the risk of post-surgery heart damage, meaning new techniques to protect patients are needed.
“Our study found that post-surgery heart damage is more common among people who have heart surgery in the morning, compared to the afternoon.
“Our findings suggest this is because part of the biological mechanism behind the damage is affected by a person’s circadian clock and the underlying genes that control it.
“As a result, moving heart surgery to the afternoon may help to reduce a person’s risk of heart damage after surgery.”
During year-long trials that ended in February 88 patients were randomly scheduled for heart valve replacement surgery in the morning or afternoon and monitored until they left hospital.
There were no deaths in either group and the average time in hospital was 12 days.
However, patients who had afternoon surgery had lower levels of heart tissue damage after surgery, compared to morning surgery patients.
The latest study, published in The Lancet, chimes with previous research suggesting heart attacks that happen in the morning may be associated with a higher risk of the damage, compared to afternoon events.
Dr Mike Knapton, associate medical director of the British Heart Foundation, said: “Thousands of people now have open heart surgery in the UK.
“These procedures can take many hours and come with a number of risks.
“The time of day appears to be a significant factor in the outcome from surgery, with better outcomes if your surgery is in the afternoon.
“If this finding can be replicated in other hospitals this could be helpful to surgeons planning their operating list, for non-urgent heart surgery.”