Effectiveness and Safety of a Clinical Assessment and 0h/1h Troponin Rule-Out Protocol

Chest pain is a common presenting complaint at the Emergency Department (ED). Many of these patients undergo lengthy assessments in the ED or are admitted which contributes to ED and hospital crowding as well as a substantial health care burden. The now commonly used high-sensitivity cardiac troponin assays enable faster rule-out of acute myocardial infarction (AMI). The European Society of Cardiology (ESC) recommend the use of a 0h/1h high-sensitivity cardiac troponin T (hs-cTnT) protocol, but all studies so far have been observational. The safety and effectiveness of the protocol when implemented in routine care is thus unknown.

The aim of this study is to determine the safety and effectiveness of the ESC 0h/1h hs-cTnT protocol, supplemented with clinical assessment and ECG, when implemented in routine care.

STUDY DESIGN:

ESC-TROP is a before-and-after implementation study with concurrent controls that will evaluate the safety and effectiveness of a 0h/1h hs-cTnT protocol. The intervention group will consist of ED chest pain patients enrolled during 10 months after implementation of this protocol in routine care at the three intervention sites, and the control groups will be chest pain patients managed at the same EDs during the corresponding 10 months of the previous year, as well as chest pain patients managed during the same before-and-after period at two EDs not implementing the protocol (concurrent controls).

OBJECTIVES:

To determine the safety and effectiveness of the ESC 0h/1h hs-cTnT protocol, supplemented with clinical assessment and ECG, when implemented in routine care.

ELIGIBILITY CRITERIA:

All patients with an ED visit with a primary complaint of non-traumatic chest pain will be identified through the electronic ED patient log and screened for eligibility.

IMPLEMENTED PROTOCOL:

ESC guidelines state that the 0h/1h hs-cTnT protocol should be used in conjunction with clinical assessment and the ECG, and these items are therefore incorporated in the protocol, which also reflects real-life practice. A 1h hs-cTnT is defined as a second hs-cTnT sample drawn 45 - 90 minutes from the sample at presentation (0h).

OUTCOMES:

Se outcomes section. Outcomes will be compared in the 10-month periods before and after the implementation at all five hospitals, and the differences in change will be compared between intervention and control hospitals.

FOLLOW-UP:

Follow-up will be performed using data from a comprehensive regional electronic patient record system as well as Swedish national registries.

DATA MANAGEMENT AND STATISTICAL ANALYSES:

Data management and statistical analyses will be performed by Clinical Studies Sweden, Forum South. For the primary safety outcome, event rate after implementation (intervention group) will be compared to event rate in the control period using a non-inferiority approach

SAMPLE SIZE:

If it is assumed that the event rate is 0.4% among discharged patients in the control period and 0.5% after implementation, 4396 discharged patients would be needed both before and after the implementation (i.e. a total of 8792) to statistically determine that the event rate after implementation is non-inferior to that in the control period, with a two-sided alpha risk of 0.05 and a power of 0.80. The non-inferiority margin has been set to 0.5 percentage units as there is consensus that a \<1% incidence of AMI/death within 30 days represents good safety for a diagnostic strategy in chest pain patients.

Based on a total of 13100 annual chest pain patients at the three EDs and a 25% exclusion rate, a study period of 10 months will give enrollment of about 8200 patients. If 55% are discharged from the ED, about 4500 patients will be discharged both before and after implementation (i.e. a total of about 9000).

With this sample size, and an estimated median ED length of stay (LOS) in discharged patients in the control group of 240 minutes, it will be possible to detect a difference in ED LOS of about 14 minutes with a power of 0.80 and alpha of 0.05. This sample size will thereby provide adequate power to detect a clinically significant difference in ED LOS for the co-primary outcome.

Eligibility Criteria:
Inclusion Criteria:

* ED presentation with a primary complaint of non-traumatic chest pain
* Age ≥18 years

Exclusion Criteria:

* A final diagnosis of STEMI during the index visit
* No hs-cTnT ordered
* Patient leaving against medical advice
* No Swedish personal identification number
* Previous enrollment
* Unwillingness to participate