Daytime variation of perioperative myocardial injury in non-cardiac surgery and effect on outcome

Objective Recently, daytimevariation in perioperative myocardial injury (PMI) has been observed in patients undergoing cardiac surgery. We aim at investigating whether daytimevariation also occurs in patients undergoing non- cardiac surgery. Methods In a prospective diagnostic study, we evaluated the presence of daytimevariation in PMI in patients at increased cardiovascular risk undergoing non- cardiac surgery, as well as its possible impact on the incidence of acute myocardial infarction (AMI), and death during 1-year follow-up in a propensity score–matchedcohort. PMI was defined as an absolute increase in high-sensitivity cardiac troponin T(hs-cTnT) concentration of ≥14 ng/L from preoperative to postoperative measurements. Results Of 1641 patients, propensity score matchingdefined 630 with similar baseline characteristics, half undergoing non- cardiac surgeryin the morning(starting from 8:00 to 11:00) and half in the afternoon (starting from 14:00 to 17:00). There was no difference in PMI incidence between both groups ( morning: 50, 15.8% (95% CI 12.3 to 20.3); afternoon: 52, 16.4% (95% CI 12.7 to 20.9), p=0.94), nor if analysing hs-cTnT release as a quantitative variable (median morninggroup: 3 ng/L (95% CI 1 to 7 ng/L); median afternoon group: 2 ng/L (95% CI 0 to 7 ng/L; p=0.16). During 1-year follow-up, the incidence of AMI was 1.2% (95% CI 0.4% to 3.2%) among morningsurgeries versus 4.1% (95% CI 2.3% to 6.9%) among the afternoon surgeries (corrected HR for afternoon surgery 3.44, bootstrapped 95% CI 1.33 to 10.49, p log-rank=0.03), whereas no difference in mortality emerged (p=0.70). Conclusions Although there is no daytimevariation in PMI in patients undergoing non- cardiac surgery, the incidence of AMI during follow-up is increased in afternoon surgeries and requires further study. Clinical trial registration NCT02573532;Results.