Heart Surgery Outcomes May Depend on Time of Day: Study

Heart surgeries that begin later in the morning may carry a slightly higher risk of death from heart-related causes compared to those performed earlier in the day, according to a large study conducted by researchers in the United Kingdom.

The study, carried out by scientists at the University of Manchester, analysed national healthcare data from more than 24,000 patients across England, Wales, and Northern Ireland. The findings suggest that the time of day when heart surgery starts could play an important role in patient outcomes, raising new questions about how surgical schedules are planned.

Researchers found that heart surgeries starting in the late morning were associated with an 18 per cent higher risk of cardiovascular death compared to procedures that began early in the morning. While the increased risk is relatively modest, it is statistically significant and could have meaningful implications when applied across large numbers of patients.

Interestingly, the study showed that the most common time for heart surgery was between 7:00 am and 9:59 am, accounting for nearly half of all procedures analysed. Although complication rates and hospital readmissions did not vary based on surgery timing, the difference in heart-related mortality highlights the need to better understand how biological rhythms may affect surgical outcomes.

The researchers believe the findings are linked to the body’s circadian rhythm, often referred to as the body clock. This internal 24-hour cycle regulates many vital functions, including heart activity, blood pressure, hormone release, and inflammation. Importantly, people’s body clocks differ — some individuals are naturally “early birds,” while others are “night owls.”

Experts suggest that aligning surgery timing with a patient’s biological rhythm could be a step toward more personalised and precision-based medicine. Even small improvements in timing-related outcomes could translate into significant benefits at a population level, especially for high-risk procedures such as heart surgery.

The researchers also emphasised that patients should not be alarmed by the findings. For most people, the difference in risk is unlikely to have a noticeable impact, and heart surgery remains a life-saving and generally safe procedure.

However, clinicians have a responsibility to explore every possible way to improve outcomes. Adjusting surgery schedules based on biological timing could be a relatively low-cost strategy to enhance patient safety in the future.

As understanding of circadian biology continues to grow, experts believe personalised scheduling of cardiac surgery may one day become part of routine care, helping ensure the best possible outcomes for patients.

With Inputs From IANS