3304High sensitive cardiac troponin i at admission and 30 minutes later to rule-in or rule-out acute myocardial infarction - Preliminary results from the RACING-MI trial

Introduction

Current ESC guidelines have introduced a 0h/1h algorithm for accelerated rule-in or rule-out of acute myocardial infarction (MI) when using assay specific high-sensitive cardiac troponin I (hs-cTnI). Several studies have investigated the diagnostic performance and safety of this approach using different hs-cTnI assays. However, little is known of the diagnostic performance of a 0h/30min algorithm.

Purpose

To evaluate the diagnostic accuracy of early rule-in or rule-out of MI after 30 minutes by applying assay specific hs-cTnI cut-off values from a recently validated 0h/1h algorithm.

Methods

We prospectively enrolled chest pain patients suggestive of MI admitted to the Emergency Department. Patients underwent serial hs-cTnI measurements at admission (0 hour) and after 3 hours according to clinical practice. In addition, hs-cTnI measurements were performed after 30 minutes. The assay specific cut-off values from the 0h/1h algorithm were applied to the 30 minute cohort (figure 1). Final diagnosis was adjudicated independently by two physicians.

Results

In total, 943 patients were included. MI was the final diagnosis in 67 (7.1%) patients. Overall, absolute hs-cTnI values after 30 minutes were significantly higher in the MI group than in the non-MI group (19.2 (Q1:Q3) 2.7–75.3) ng/L versus 0.1 (0.2–0.7) ng/L, p<0.001). When applying the assay-specific hs-cTnI cut-off valuesfor the 0h/1h algorithmto the 30 minute patient cohort, 52.4% of patients were classified as rule-out with a negative predictive value of 100% (95% CI: 99.2–100). In total, 8.5% were classified as rule-in with a positive predictive value of 83.8% (95% CI: 74.2–90.3). Sensitivity was 100% (95% CI: 94.6–100) and specificity was 97.4% (95% CI: 95.7–98.6). Overall, 39.1% were assigned to the observational zone with a 3.5% prevalence of MI.

Conclusions

The use of assay specific hs-cTnI measurement at admission (0h) and 30 min later can be used to safely rule-out MI. This indicates that it might be safe to develop a 0h/30min algorithm and hereby reduce time to diagnosis even further. NCT03634384.

Acknowledgement/Funding

Randers Regional Hospital, A.P Møller Foundation, Boserup Foundation, Korning Foundation, Højmosegård Grant, Siemens Healthcare (TNIH assays), etc.

P2673Challenging time limits: Using a single high-sensitive troponin I to rule-out acute myocardial infarction in early presenters

Introduction

According to ESC guidelines, an acute myocardial infarction (MI) can be excluded without serial troponin measurements in patients presenting with a single high-sensitive troponin below the 99th percentile and chest pain starting >6 hours prior to admission. However, it is unclear if single-testing of high-sensitive troponin can rule-out MI in early presenters.

Purpose

To investigate the diagnostic performance of a single value of high-sensitive cardiac troponin I (hs-cTnI) at presentation for ruling-out MI in patients presenting with chest pain to the Emergency Department irrespective of chest pain onset.

Methods

We conducted a substudy of preliminary data from the RACING-MI trial. We included patients presenting with chest pain suggestive of MI to the Emergency Department of a Regional Hospital. We used the Siemens hs-cTnI (Siemens Healthcare, TNIH, Limit of detection: 2.21 ng/L) and a diagnostic cut-off value <3 ng/L to rule-out MI at presentation. Two physicians independently adjudicated the final diagnosis based on all clinical information. Patients were stratified based on time from chest pain onset to hospital admission as very early (0–3 hours), early (3–6 hours) and late presenters (>6 hours).

Results

We included 989 patients with available hs-cTnI results at admission. MI was confirmed in 82 (8.3%) patients. Using hs-cTnI <3 ng/L as diagnostic cut-off value at presentation, 302 (30.5%) patients without MI were classified as rule-out. Overall, the negative predictive value (NPV) for MI was 100% (95% CI 98.7–100).

Based on chest pain onset, 33.8% of patients were classified as very early, 12.8% as early, and 42.7% as late presenters, with 10.7% patients with unreported/unknown onset. NPV was 100% (95% CI 96.5–100) for very early, 100% (95% CI 88.3–100) for early and 100% (95% CI 97.3–100) for late presenters.

Conclusions

Using a single hs-cTnI value <3ng/L as diagnostic cut-off to rule-out MI seems to be safe and to allow rapid rule-out of MI in patients presenting with chest pain to the emergency department, even in very early presenters.

ClinicalTrials.gov Identifier: NCT03634384.

Acknowledgement/Funding

Randers Regional Hospital, A.P Møller Foundation, Boserup Foundation, Korning Foundation, Højmosegård Grant, Siemens Healthcare (TNIH assays), etc.