Effect of a national guideline on postoperative troponin surveillance: a retrospective cohort study

Purpose: We aimed to evaluate the effect of the 2017 Canadian Cardiovascular Society (CCS) guidelines on troponin surveillance after noncardiac surgery. Methods: This was a single-centre, retrospective, observational study. Patients aged 40 yr or older undergoing intermediate- to high-risk elective noncardiac surgery between 2016 and 2021 were included. We compared the number and percentage of troponin tests ordered before and after the guidelines were published and compared patient characteristics, specifically cardiovascular comorbidity, using odds ratio’s (OR) with 95% confidence intervals (CIs). Outcomes were myocardial injury, myocardial infarction (MI), and in-hospital mortality. Results: The cohort included 36,386 patients and the median age was 63 yr. Between 2016 and 2018, troponin surveillance was done in 2,461 (13%) of the 19,046 patients, compared with 2,398 (14%) of the 17,340 patients who had surgery between 2019 and 2021 (OR, 1.08; 95% CI, 1.02 to 1.15). Patients who had surgery in the second period had less cardiovascular comorbidity; the adjusted OR for troponin surveillance was 1.14 (95% CI, 1.07 to 1.21). In the two periods, troponin was elevated in 561 (2.9%) and 470 (2.7%) patients, an MI was documented in 54 (0.3%) and 36 (0.2%) patients, and 95 (0.5%) and 73 (0.4%) patients died, respectively. After adjustment for baseline differences in the two periods, the ORs for MI and mortality were 0.83 (95% CI, 0.54 to 1.27) and 0.88 (95% CI, 0.64 to 1.19), respectively. Conclusion: Although the odds of troponin ordering were slightly but significantly higher after publication of the CCS guidelines, the odds for detecting an MI and for mortality did not change.