In another part of the study, the researchers monitored the health of 88 heart valve replacement surgery patients until they left the hospital. During the average follow-up of 12 days, patients who had afternoon surgery had less heart tissue damage than those who had morning surgery.
The researchers then tested 30 heart tissue samples from this group of patients and found that samples from afternoon surgery patients more quickly regained their ability to contract when put in conditions that replicated the heart refilling with blood.
Genetic analysis of the heart tissue samples also revealed that 287were more active in the samples from afternoon surgery patients than those from morning surgery patients.
That suggests that the, and that open heart surgery outcomes reflect the heart’s poorer ability to repair in the morning, the researchers said.
The findings were published Oct. 26 in The Lancet medical journal.
“Our study found thatheart damage is more common among people who have heart surgery in the morning, compared to the afternoon,” Montaigne said in a journal news release.
“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,” he added.
Montaigne and his colleagues also said it may be possible to develop drugs that can influence circadian clock-related genes to protect the heart during surgery.