An algorithm for rule-in and rule-out of acute myocardial infarction using a novel troponin I assay

Area of Science:

• Cardiology
• Biochemistry
• Emergency Medicine

Background:

• Acute myocardial infarction (AMI) diagnosis relies on timely and accurate risk stratification.
• Current diagnostic protocols for chest pain patients in the emergency department can be lengthy.
• Novel biomarkers and algorithms are needed to expedite AMI rule-out and rule-in.

Purpose of the Study:

• To develop and validate a hybrid algorithm for AMI rule-out and rule-in.
• To utilize a novel cardiac troponin I (cTnI) assay for serial measurements.
• To assess the algorithm's performance at presentation and after 2 hours in emergency department patients.

Main Methods:

• Algorithm derivation and validation in two multicenter cohorts totaling 1197 chest pain patients.
• Inclusion criteria: emergency department presentation with symptom onset within 12 hours.
• Independent adjudication of index diagnosis and 30-day cardiovascular events.

Main Results:

• At presentation, 32.6% were ruled out, 6.1% ruled in; after 2 hours, an additional 22% were ruled out and 9.8% ruled in.
• Overall, 54.6% ruled out (NPV 99.4%), 15.8% ruled in (PPV 74.5%).
• High diagnostic performance achieved with no deaths in the rule-out group during 30-day follow-up.

Conclusions:

• A novel two-step algorithm using cTnI measurements efficiently manages acute chest pain patients.
• The algorithm enables rapid rule-in/rule-out decisions, with over a third of patients classified at presentation and another third after 2 hours.
• This strategy balances diagnostic speed with high negative and positive predictive values.