Study: Patients who undergo heart surgery during this time of day have better chance for survival

Does the time of day you go under the knife for open heart surgery make a difference?

Yes, it does − a life or death difference, according to a new report

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Researchers from France recently conducted an experiment, published in The Lancet, to determine how surgery time can affect a patient’s recovery. 

To do so, they first examined the medical records of about 600 people who’d undergone heart valve replacement surgery. Half had the procedure in the morning, while the other half had it in the afternoon. For 500 days, they kept an eye out for any major cardiac events, such as heart attacks, heart failure and death from heart disease. 

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After analyzing the results, those who had surgery in the afternoon were 50 percent less likely to have a major cardiac event. That would be one less major cardiac event per 11 patients, the study found. 

In the second part of the experiment, they observed the health of 88 patients, who had heart valve replacement surgery, during their stay at the hospital. They also tested their heart tissue samples.

After 12 days, they found that “post-surgery heart damage is more common among people who have heart surgery in the morning," lead author David Montaigne said in a statement

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But why is that?

Scientists are associating the time of the surgery with the body’s biological clock. The heart tissue samples revealed nearly 300 genes linked to the circadian clock. They were more active in the afternoon than morning, the study revealed. 

"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," Montaigne said.

Scientists hope to conduct more studies to confirm their results. They said they may even be able to develop medication that can alter the circadian clock in preparation for open heart surgery.

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