Validation of the Ottawa Troponin Pathway

Area of Science:

• Cardiology
• Emergency Medicine
• Clinical Diagnostics

Background:

• The Ottawa Troponin Pathway (OTP) was designed to enhance the accuracy of diagnosing Non-ST elevation myocardial infarction (NSTEMI) through serial troponin I (TnI) measurements.
• This study aimed to validate the OTP in a specific patient cohort: those with TnI values exceeding the 99th percentile upper reference limit (>45 ng/L).

Purpose of the Study:

• To validate the diagnostic accuracy of the Ottawa Troponin Pathway (OTP) in emergency department patients presenting with symptoms suggestive of acute coronary syndrome (ACS) and elevated troponin I levels.
• To assess the OTP's performance in identifying Non-ST elevation myocardial infarction (NSTEMI) in patients with troponin I values above the 99th percentile.

Main Methods:

• A retrospective health records review was conducted on adult patients presenting to two emergency departments with NSTEMI symptoms.
• Data collected included baseline characteristics, emergency department management, disposition, and 30-day outcomes (cardiac death, unknown cause death, or NSTEMI diagnosis).
• Inclusion criteria required at least two serial TnI measurements with at least one value exceeding 45 ng/L.

Main Results:

• Out of 635 patients, 107 were diagnosed with NSTEMI within 30 days. The OTP demonstrated 100% sensitivity (95% CI 96.6%-100%) and 32.2% specificity (95% CI 28.2%-36.4) for NSTEMI diagnosis.
• Patients with TnI values ≥100 ng/L (n=418) had a higher NSTEMI diagnosis rate (103 cases) compared to those with TnI >45 ng/L but <100 ng/L (4 NSTEMI cases out of 217 patients).

Conclusions:

• The Ottawa Troponin Pathway (OTP) is validated for use in patients with elevated troponin I levels (>99th percentile) presenting with symptoms concerning for ACS.
• Implementing the OTP can facilitate earlier patient referral and discharge, potentially alleviating emergency department overcrowding.