Management of Patients Suspected for non-ST elevation-acute Coronary Syndrome in the Prehospital Phase

Figures & data

Table 1. Handheld point of care cardiac troponin devices and specifications.

Device	Manufacturer	Troponin	99th URL	Measuring range	Time to result	Specimen collection
Cobas h 232 POC system	Roche Diagnostics	Troponin T	• NA	40–2000 ng/l	12 min	• Heparinized venous whole blood
Atelica^® VTLi Patient-side Immunoassay Analyzer	Siemens Healthineers	High sensitivity troponin I	• Overall 22.9 ng/l • Male 27.1 ng/l • Female 18.5 ng/l	LoD* – 1250 ng/l *LoD plasma 1.2 ng/l *LoD whole blood 1.6 ng/l	∼8 min	• Whole blood (lithium heparin) • Venous (lithium heparin) • Capillary
i-STAT™	Abbott	Troponin I	• 0.08 ng/ml Each institution should establish its own reference range using the i-STAT cTnI assay.	0.00–50.00 ng/ml Performance characteristics have not yet been established for cTnI values above 35.00 ng/ml	10 min	• Heparinized whole blood or plasma samples collected in syringes or evacuated tubes containing lithium heparin • Non-heparinized whole blood samples tested within 1 min of drawing from a patient into a plastic syringe or plastic evacuated tube containing no additives
Triage MeterPro	Quidel	High sensitivity troponin I	• Overall 20.5 ng/l • Male 25.7 ng/l • Female 14.4 ng/l	1.0–1000 ng/l	<20 min	• EDTA whole blood or plasma

*The measuring range of this device is from the limit of detection (LoD) to 1250 ng/l. For plasma this LoD is 1.2 ng/l, for whole blood 1.6 ng/l.

99th URL: The 99th percentile upper reference limit; cTnI: Cardiac troponin I; EDTA: Ethylenediaminetetraacetic acid; LoD: Limit of detection.

Table 2. Calculation of the history, electrocardiogram, age, risk factors and troponin score.

HEART	Characteristics	Points
History (anamnesis)	Highly suspicious	2
	Moderately suspicious	1
	Slightly suspicious	0
ECG	Significant ST-segment deviation	2
	Nonspecific repolarization disturbance/LBBB/PM	1
	Normal	0
Age	≥65 years	2
	>45 and <65 years	1
	≤45 years	0
Risk factors^†	≥3 risk factors or history of atherosclerotic disease	2
	1 or 2 risk factors	1
	No known risk factors	0
Troponin	≥3× normal limit	2
	1-2× normal limit	1
	Normal limit or lower	0
Total

† Risk factors: hypercholesterolemia, hypertension, diabetes mellitus, cigarette smoking, family history of atherosclerotic disease, BMI >30 kg/m².

ECG: Electrocardiogram; HEART: History, ECG, Age, Risk factors and initial Troponin; LBBB: Left bundle branch block; PM: Pacemaker.

Table 3. Cardiac troponin cut-off values within the modified history, electrocardiogram, age, risk factors and troponin score.

Troponin score in modified HEART-score	hs-cTnT	hs-TnI (assay dependent)
2	≥14 ng/l	≥99th percentile URL
1	≥5 and ≤13 ng/l	≥LoQ, ≤99th percentile URL
0	≤4 ng/l	<LoQ

HEART: History, ECG, Age, Risk factors and Troponin; hs-cTnT: High-sensitivity cardiac troponin T; hs-cTnI: High-sensitivity cardiac troponin I; LoQ: Limit of quantitation; POC: Point of care; URL: Upper-reference limits.

Figure 1. Flowchart of the new pathway for the management of patients suspected for non-ST-elevation acute coronary syndrome.

ED: Emergency department; GP: General practitioner; HEART: History, ECG, Age, Risk factors and Troponin; hs-cTn: High-sensitivity cardiac troponin; NSTE-ACS: Non-ST-elevation acute coronary syndrome; NSTEMI: Non-ST elevation myocardial infarction; STEMI: ST-elevation myocardial infarction.