Direct Comparison of Four Very Early Rule-Out Strategies for Acute Myocardial Infarction Using High-Sensitivity Cardiac Troponin I
Background—Four strategies for very early rule-out of acute myocardial infarction (AMI) using high-sensitivity cardiac troponin I (hs-cTnI) have been identified. It remains unclear which strategy is most attractive for clinical application.
Methods—We prospectively enrolled unselected patients presenting to the emergency department (ED) with symptoms suggestive of AMI. The final diagnosis was adjudicated by two independent cardiologists. Hs-cTnI levels were measured at presentation and after 1h in a blinded fashion. We directly compared all four hs-cTnI-based rule-out strategies: limit of detection (LOD, hs-cTnI<2ng/L), single cut-off (hs-cTnI<5ng/L), 1h-algorithm (hs-cTnI<5ng/L and 1h-change<2ng/L), and the 0/1h algorithm recommended in the European Society of Cardiology (ESC) guideline combining LOD and 1h-algorithm.
Results—Among 2828 enrolled patients, AMI was the final diagnosis in 451 (16%) patients. The LOD approach ruled-out 453 patients (16%) with a sensitivity of 100% (95% CI, 99.2-100%), the single cut-off 1516 patients (54%) with a sensitivity of 97.1% (95% CI, 95.1-98.3%), the 1h-algorithm 1459 patients (52%) with a sensitivity of 98.4% (95% CI, 96.8-99.2%), and the 0/1h algorithm 1463 patients (52%) with a sensitivity of 98.4% (95% CI, 96.8-99.2%). Predefined subgroup analysis in early presenters (≤2h) revealed significantly lower sensitivity (94.2%, interaction p=0.03) of the single cut-off, but not the other strategies. Two-year survival was 100% with LOD and 98.1% with the other strategies (p<0.01 for LOD vs. each of the other strategies).
Conclusions—All four rule-out strategies balance effectiveness and safety equally well. The single cut-off should not be applied in early presenters, while the three other strategies seem to perform well also in this challenging subgroup.
Clinical Trial Registration—https://clinicaltrials.gov/ Identifier: NCT00470587
- Acute myocardial infarction
- Rule-out strategies
- Diagnosis of AMI
- acute myocardial infarction
- acute coronary syndrome
- Received September 24, 2016.
- Revision received February 19, 2017.
- Accepted March 1, 2017.