Time of day of cardiac surgery and postoperative outcomes in the <scp>UK</scp> : a secondary analysis of linked national datasets

Time-of-day variation in postoperative death due to cardiovascular disease following cardiac surgery was observed, with the highest risk seen in late morning procedures. These findings suggest that intra-operative or organisational factors specific to this period may influence outcomes. Future research should explore whether individual circadian phenotypes or chronotypes contribute to this variation, supporting a move towards precision and personalised scheduling of cardiac surgery to optimise patient outcomes.