Open heart surgery better in afternoon

Researchers have established that half of the patients undergoing surgery in the afternoon had a 50 per cent lower risk of a major cardiac event. FILE PHOTO | NMG 

Open heart surgeries performed in the afternoon have better health outcomes than those done in the morning, a new study shows.

The research, published in the ‘Lancet’, suggests the heart is stronger and better able to withstand surgery in the afternoon than the morning. The research involved a follow-up on 596 people going for heart valve replacement where half went for surgery in the morning.

Researchers established that half of the patients undergoing surgery in the afternoon had a 50 per cent lower risk of a major cardiac event. Those going for the surgery in the morning had an 18 per cent higher risk of a major cardiac event compared to nine per cent of those going for the surgeries in the afternoon.

The study shows a link between a person’s circadian clock — the internal body clock that controls when people sleep, eat and wake up — and the risk of heart damage.

Laboratory tests on heart samples tissue found that afternoon surgery samples more quickly regained their ability to contract when put in conditions that replicated the heart refilling with blood. The study was done from January 2009 to December 2015.

A DNA analysis done shows 287 genes linked to the circadian clock were more active in the afternoon.

A research carried out previously suggested that cardiovascular events such as heart attacks occurring in the morning may be associated to higher risk of the damage when compared to those happening in the afternoon, however no supporting reasons were unveiled.

“Currently, there are few other surgical options to reduce the risk of post-surgery heart damage, meaning new techniques to protect patients are needed,” said author Professor David Montaigne, University of Lille, France.

“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.”

The research authors say the study will need to be replicated in larger trials to fully understand the association between the circadian clock and damage after heart surgery.