Comprehensive validation of early diagnostic algorithms for myocardial infarction in the emergency department

Abstract

Objective: To comprehensively evaluate diagnostic algorithms for myocardial infarction using a high-sensitivity cardiac troponin I (hs-cTnI) assay.

Patients and methods: We prospectively enrolled patients with suspected myocardial infarction without ST-segment elevation from nine emergency departments in Japan. The diagnostic algorithms evaluated: (i) based on hs-cTnI alone, such as the European Society of Cardiology (ESC) 0/1-h or 0/2-h and High-STEACS pathways; or (ii) used medical history and physical findings, such as the ADAPT, EDACS, HEART, and GRACE pathways. We evaluated the negative predictive value (NPV), sensitivity as safety measures, and proportion of patients classified as low or high-risk as an efficiency measure for a primary outcome of type 1 myocardial infarction or cardiac death within 30 days.

Results: We included 437 patients, and the hs-cTnI was collected at 0 and 1 hours in 407 patients and at 0 and 2 hours in 394. The primary outcome occurred in 8.1% (33/407) and 6.9% (27/394) of patients, respectively. All the algorithms classified low-risk patients without missing those with the primary outcome, except for the GRACE pathway. The hs-cTnI-based algorithms classified more patients as low-risk: the ESC 0/1-h 45.7%; the ESC 0/2-h 50.5%; the High-STEACS pathway 68.5%, than those using history and physical findings (15-30%). The High-STEACS pathway ruled out more patients (20.5%) by hs-cTnI measurement at 0 hours than the ESC 0/1-h and 0/2-h algorithms (7.4%).

Conclusions: The hs-cTnI algorithms, especially the High-STEACS pathway, had excellent safety performance for the early diagnosis of myocardial infarction and offered the greatest improvement in efficiency.

Figure 1.

Patient flows. The research blood samples at presentation could not be collected from 17 patients due to overlooking to collect blood or mishandling. We stopped collecting research blood samples if patients had an emergency catheterization (deemed unnecessary at presentation but deemed necessary based on the course of events or troponin results afterwards) or hospitalization. ACS, acute coronary syndrome; CAG, coronary angiography; ECG, electrocardiography; hs-cTnI, high-sensitivity cardiac troponin I; h, hours. The sum of ^a, ^b and 2 is 437.

Figure 2.

Classified timings and proportions. Timing and proportion of patients for rule-out, rule-in and not classified. ADAPT, 2-Hour Accelerated Diagnostic Protocol to Assess Patients With Chest Pain Symptoms using Troponins; EDACS, Emergency Department Assessment of Chest Pain Score; GRACE, Global Registry of Acute Coronary Events; HEART, History, Electrocardiography, Age, Risk factors, Troponin.