Mode
Text Size
Log in / Sign up

Cochrane review finds very low-certainty evidence on early versus late cardiac surgery start times in FranceHeart Surgery Timing May Lower Heart Damage Risk

AI-generated summary of the cited source, checked by automated accuracy review. How we work

Key Takeaway
Note very low-certainty evidence on scheduling impact from single French study.

This Cochrane systematic review examines the effects of early versus late surgical start times for adults undergoing on-pump cardiac surgery. The analysis relies on a single study conducted in France involving 88 participants. Because only one study met inclusion criteria, the authors did not perform a meta-analysis and instead synthesized results descriptively.

The review assessed short-term mortality, long-term mortality, and perioperative myocardial infarction. No study reported data for short-term or long-term mortality, with no deaths in both groups. For perioperative myocardial infarction, the relative risk was 0.29 with a 95% CI of 0.06 to 1.30. Perioperative myocardial injury was lower in late surgery compared to early surgery, with a mean difference of -46 ng/L x 72 h (95% CI -79 to -13).

Other outcomes showed no evidence of a difference. New-onset postoperative atrial fibrillation had a relative risk of 0.75 (95% CI 0.40 to 1.40). Left ventricular ejection fraction less than 45% at discharge had a relative risk of 0.40 (95% CI 0.08 to 1.95). Length of hospital stay showed a mean difference of 0.00 (95% CI -1.48 to 1.48). Need for inotropic support had a relative risk of 0.25 (95% CI 0.03 to 2.15).

The authors note very low-certainty evidence for perioperative myocardial infarction and length of hospital stay. More research is needed to determine whether scheduling heart surgery later in the day improves patient outcomes. The evidence is very uncertain about the effects of early versus late surgical start time.

Heart Surgery Timing May Lower Heart Damage Risk

Imagine waking up for a major heart operation. You trust your medical team to save your life. But what if the time of day matters more than you think?

Your body follows a natural clock. This rhythm controls your heart rate and blood pressure. Morning hours feel different from afternoon hours for your organs.

Doctors have long wondered if afternoon surgery helps. Some think it reduces damage when blood returns to the heart. Others disagree with this idea.

The Morning Routine Problem

Heart surgery is a big event for your body. It requires a lot of energy and focus. Most hospitals schedule these operations early in the day.

This schedule works for many reasons. Surgeons are fresh and tiredness is low. Equipment is ready and waiting. Staff are fully prepared.

But here is the catch. Your heart might not be ready for morning stress. The body repairs itself better at night. This natural healing cycle could be disrupted by early surgery.

A Factory Analogy

Think of your heart muscle like a busy factory. Workers repair machines while the factory sleeps. This happens during your rest time.

Morning surgery forces the factory to work while it should be resting. Afternoon surgery lets the factory finish repairs before the shift starts.

This simple idea explains why timing matters. It is not about magic. It is about working with your biology.

Researchers looked at one specific study from France. They watched 88 adults getting valve replacements. These patients had surgery with a heart machine running.

The team compared morning operations to afternoon ones. They measured heart damage carefully over three days. They also checked for other risks like heart rhythm problems.

The results were interesting but not perfect. No one died in either group. This is good news for everyone.

However, the afternoon group showed less heart muscle injury. The team measured this with a specific blood test. Lower numbers mean less damage to the heart tissue.

But There Is A Catch

That is not the full story. The study was small with only 88 people. One study is not enough to change hospital rules.

We do not know if this works for all heart surgeries. We also lack data on long-term survival. More research is needed to be sure.

Talk to your doctor about timing if you need surgery. Ask if your hospital considers the time of day. Some places may already schedule certain cases later.

Do not delay needed surgery to wait for afternoon. Your health comes first. But you can ask questions about your specific case.

Scientists need more large studies to confirm these findings. They will look at different types of heart surgery. They will also check if this helps everyone equally.

Until then, hospitals will likely keep their current schedules. Safety and staff availability remain top priorities. This new data adds to the conversation.

This does not mean afternoon surgery is better for everyone.

The goal is to help patients heal faster. Timing is just one piece of the puzzle. Doctors will weigh all the facts before making changes.

Your heart deserves the best care possible. Understanding the science helps you make informed choices. Stay curious and ask questions during your appointments.

Study Details

Study typeSystematic review
EvidenceLevel 1
PublishedApr 2026
View Original Abstract ↓
Rationale Circadian rhythms affect cardiovascular function, and the timing and severity of stroke and myocardial infarction (commonly known as a heart attack). Afternoon cardiac surgery may improve outcomes by reducing ischaemia‐reperfusion injury (i.e. reducing tissue damage caused when blood supply returns to tissue (reperfusion) after a period of oxygen deprivation (ischaemia)). However, the evidence is conflicting. This systematic review assessed the impact of surgical timing on clinical outcomes after cardiac surgery. Objectives To assess the effects of early versus late surgical start times for on‐pump cardiac surgery on mortality, cardiac outcomes, and quality of life. Search methods We searched CENTRAL, MEDLINE, Embase, and Web of Science Conference Proceedings Citation Index ‐ Science, along with ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform trials registers. We also conducted reference checking, citation searching, and contacted study authors to identify studies for inclusion. The latest search date was 26 January 2025. Eligibility criteria We included randomised controlled trials (RCTs) in adults undergoing cardiac surgery comparing late with early surgical start times. We excluded non‐randomised studies and studies in children. Outcomes Our critical outcomes were short‐term mortality (≤ 30 days postoperative), long‐term mortality (> 30 days postoperative), and perioperative myocardial infarction. Other important outcomes were perioperative myocardial injury, postoperative atrial fibrillation, left ventricular ejection fraction, lengths of intensive care unit (ICU) and hospital stays, and quality of life. Risk of bias We used the Cochrane Risk of Bias 2 tool to assess bias in the included RCTs. Synthesis methods As only one study met the inclusion criteria, we did not perform meta‐analysis. We synthesised results descriptively, and used GRADE to assess the certainty of the evidence for specified outcomes. Included studies We included one study with 88 participants. The included study was conducted in France, and reported on differences in outcomes between morning and afternoon on‐pump elective aortic valve replacement in adults. Synthesis of results Critical outcomes No study reported short‐term or long‐term mortality data for early versus late surgical start times for on‐pump cardiac surgery. In the included study, there was no evidence of a difference regarding in‐hospital mortality between groups, with no deaths in both groups (risk ratio (RR) and 95% confidence interval (CI) not estimable; 1 study, 88 participants). The evidence is very uncertain about the effect of early versus late surgery on perioperative myocardial infarction (RR 0.29, 95% CI 0.06 to 1.30; 1 study, 88 participants, very low‐certainty evidence). Important outcomes There was evidence of lower perioperative myocardial injury as measured by cumulative troponin release over 72 hours in those undergoing late surgery compared to early surgery (MD −46 ng/L × 72 h, 95% CI −79 to −13; 1 study, 88 participants). In the included study, there was no evidence of a difference in new‐onset postoperative atrial fibrillation during hospital stay between groups (RR 0.75, 95% CI 0.40 to 1.40; 1 study, 88 participants). No study reported differences in left ventricular ejection fraction at discharge as a continuous variable for early versus late surgical start times for on‐pump cardiac surgery. In the included study, there was no evidence of a difference in left ventricular ejection fraction < 45% at discharge between groups (RR 0.40, 95% CI 0.08 to 1.95; 1 study, 88 participants). No study reported differences in length of ICU admission for early versus late surgical start times for on‐pump cardiac surgery. There was no evidence of a difference in need for inotropic support between groups in the included study (RR 0.25, 95% CI 0.03 to 2.15; 1 study, 88 participants). The evidence is very uncertain about the effect of late surgery on length of hospital stay (MD 0.00, 95% CI −1.48 to 1.48; 1 study, 88 participants, very low‐certainty evidence). No study reported on the outcome of quality of life. Authors' conclusions The evidence is very uncertain about the effects of early versus late surgical start time for the outcomes of perioperative myocardial infarction and length of hospital stay. We found no data for the outcomes of short‐term or long‐term mortality, left ventricular ejection fraction, length of ICU stay, or quality of life. Late surgical start time could reduce the risk of perioperative myocardial injury as estimated by cumulative troponin release over 72 hours. More research is needed to determine whether scheduling heart surgery later in the day improves patient outcomes. Funding This Cochrane review had no dedicated funding. Registration Protocol (2022) DOI: 10.1002/14651858.CD014901 PICOs PICOs Population Intervention Comparison Outcome
Free Newsletter

Clinical research that matters. Delivered to your inbox.

Join thousands of clinicians and researchers. No spam, unsubscribe anytime.