Adherence to Accelerated Diagnostic Protocol for Chest Pain in Five Emergency Departments in Canada

In this study we sought to to assess the extent to which emergency physicians adhered to an institutional protocol for rapid chest pain assessment that incorporates a high sensitivity troponin I (hs-TnI) assay. We also sought to characterize clinical outcomes stratified by protocol adherence.

We conducted a retrospective cohort study that included all adult patients presenting to five major metropolitan hospital emergency departments (ED) with suspected cardiac chest pain who had at least one troponin measured. The study period was November 9, 2020-June 20, 2022. The primary outcome was protocol adherence for indeterminate-risk and high-risk patients, as defined by the protocol in use at the time of each patient's presentation to hospital. Adjusted odds ratios (aOR) are reported with associated 95% confidence intervals.

A total of 14,027 patients were included in the study, among whom 8,962 (63.9%) were classified as low risk, 4,064 (29.0%) as indeterminate risk, and 1,001 (7.1%) who were in the high-risk/rule-in group. Overall, 35.9% of patients had care that adhered to the chest pain pathway protocol-22.1% of indeterminate-risk patients and 91.6% of high-risk/rule-in patients. Protocol adherence among indeterminate-risk patients was 6.6% when the initial troponin was in the range of 4-19 nanograms per liter (ng/L) and 75.4% for initial troponin levels 20-99 ng/L. Male sex was most strongly associated with protocol adherence; among those receiving adherent care, 65.8% were male compared to 34.2% female (aOR 1.67; 95% CI, 1.46-1.91). Patients in the non-adherent group with an initial troponin 4-19 ng/L experienced a significantly higher incidence of major adverse cardiac events (4.5% vs 1.7%, P < .001), compared to those in the low-risk group.

Adherence to proposed assessment protocols for patients presenting to the ED with chest pain was low. This lack of adherence appears to disproportionally affect females and is associated with poor outcomes. Improving adherence to evidence-based guidelines in this setting is urgently needed.