Validation of a rapid diagnostic algorithm for diagnosis of myocardial infarction using a high-sensitivity cardiac troponin assay
Authors: Lehmacher J , Toprak B , Soerensen N A , Bei Der Kellen R , Hartikainen T S , Haller P M , Schock A , Twerenbold R , Zeller T , Blankenberg S , Westermann D , Neumann J T 
Published: October 2022

Abstract

Background
As acute chest pain is one of the main reasons for presentation in emergency departments, early identification of patients with myocardial infarction (MI) is of crucial importance. Current guidelines recommend the application of rapid 0h/1h diagnostic algorithms using high-sensitivity cardiac troponin (hs-Tn) for the diagnosis of MI. Several hs-Tn assays have been evaluated and assay-specific algorithms have been developed, achieving great diagnostic performance. Yet, for some of these assays, existing data is limited.

Objective
We aimed to evaluate the diagnostic performance and prognostic value of a rapid 0/1h diagnostic algorithm for Access II hs-TnI as recommended by the European Society of Cardiology (ESC).

Methods
In the prospective Biomarkers in Acute Cardiac Care study enrolling patients presenting with suspected MI to the emergency department, we measured concentrations of Access II hs-TnI at presentation and after 1 hour. Final diagnoses were independently adjudicated by two cardiologists according to the 4th Universal Definition of MI using Elecsys hs-TnT. Parameters for diagnostic performance were calculated, when applying the ESC 0/1h algorithm. Additionally, to assess the prognostic utility of this ESC 0h/1h algorithm, we performed survival analyses for the composite of all-cause mortality and incident MI at three years, computing Kaplan-Meier-curves and Cox-regressions adjusted for common cardiovascular risk factors as well as pre-existing coronary artery disease and congestive heart failure.

Results
Of 1879 enrolled patients, 257 (14%) were diagnosed with NSTEMI. Median age was 63 years, 64.3% were males. When applying the ESC 0/1h algorithm using Access II hs-TnI, 44.5% of patients were ruled-out with a sensitivity of 97.7% (95% CI; 95.0, 99.1) and a negative predictive value (NPV) of 99.3% (95% CI; 98.4, 99.7). Similarly, 20.3% of patients were ruled-in with a specificity of 88.0% (95% CI; 86.3%, 89.6%) and a positive predictive value (PPV) of 50.8% (95% CI; 45.7, 55.9) whereas 35.1% remained in the observe group (Table 1). Three-year event rates differed substantially between patients triaged towards the rule-out (2.9%), observe (16.1%) and rule-in group (18.4%, log-rank p&lt;0.001; Figure 1). Adjusted hazard ratios confirmed a significantly worse prognosis for patients in the observe group (HR 2.51 [95% CI; 1.56, 4.04], p=0.001) and rule-in group (HR 3.55 [95% CI; 2.18, 5.79], p&lt;0.001), when compared to the rule-out group.

Conclusion
The ESC 0/1h algorithm for Access II hs-TnI allows a save and efficient rapid triage of patients with suspected MI and harbours prognostic utility for incident MI and all-cause mortality.

Funding Acknowledgement
Type of funding sources: Private company. Main funding source(s): German Center of Cardiovascular Research (DZHK)Abbott Diagnostics