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Point-of-Care Troponin at 0 and 2 Hours in Suspected AMI
Quick Takes
- The current analysis aimed to derive and validate the clinical performance of a 0-/2-h algorithm using a novel whole blood point-of-care (POC) (8-minute turnaround time) hs-cTnI assay (Siemens POC Atellica VTLi) using data from two international multicenter studies.
- Patients with a 0-hour hs-cTnI <4 ng/L or 0-hour <6 ng/L with 2-hour delta of <5 ng/L were considered low risk and 0- and 2-hour strategy had a 99.9% negative predictive value for ruling out AMI.
- The high-risk metrics (0-hour >60 ng/L or delta change >15 ng/L) identified 5.4% of patients with a specificity of 98.5% (95% CI, 96.6%-99.4%) and a positive predictive value of 74.5% (95% CI, 62.7%-83.6%) for index AMI.
Study Questions:
Can a 2-hour (0 and 2 hours) point-of-care (POC) high-sensitivity cardiac troponin I (hs-cTnI) strategy be safely applied in emergency patients with suspected acute myocardial infarction (AMI)?
Methods:
In two international, multicenter, prospective, observational studies of adult emergency patients (1,486 in the derivation cohort and 1,796 in the validation cohort) with suspected AMI, hs-cTnI (Siemens Atellica® VTLi) was measured at admission and 2 hours later. Adjudicated final diagnoses utilized the hs-cTn assay in clinical use. A risk stratification algorithm was derived and validated. The primary diagnostic outcome was index AMI (Types 1 and 2). The primary safety outcome was 30-day major adverse cardiac events incorporating AMI and cardiac death.
Results:
Overall, 81 (5.5%) and 88 (4.9%) patients in the derivation and validation cohorts, respectively, had AMI. The 2-hour algorithm defined 66.1% as low risk with a sensitivity of 98.8% (95% confidence interval [CI], 89.3%-99.9%) and a negative predictive value of 99.9 (95% CI, 99.2%-100%) for index AMI in the derivation cohort. In the validation cohort, 53.3% were low risk with a sensitivity of 98.9% (95% CI, 92.4%-99.8%) and a negative predictive value of 99.9% (95% CI, 99.3%-100%) for index AMI. The high-risk metrics identified 5.4% of patients with a specificity of 98.5% (95% CI, 96.6%-99.4%) and a positive predictive value of 74.5% (95% CI, 62.7.%-83.6%) for index AMI.
Conclusions:
A 2-hour algorithm using a POC hs-cTnI concentration enables safe and efficient risk assessment of patients with suspected AMI. The short turnaround time of POC testing may support significant efficiencies in the management of the large proportion of emergency patients with suspected AMI.
Perspective:
The current analysis aimed to derive and validate the clinical performance of a 0-/2-hour algorithm using a novel whole blood POC (8-minute turnaround time) hs-cTnI assay (Siemens POC Atellica VTLi) using data from two international multicenter studies. Findings support the 2-hour strategy to determine disposition in the majority of patients, especially patients at low risk for AMI. Patients with a 0-hour hs-cTnI <4 ng/L or 0-hour <6 ng/L with 2-hour delta of <5 ng/L were considered low risk and 0- and 2-hour strategy had a 99.9% negative predictive value for ruling out AMI. There remains a need to apply this approach more broadly in clinical scenarios in and outside the emergency department to assess the impact of this proposed strategy.
Clinical Topics: Acute Coronary Syndromes, ACS and Cardiac Biomarkers
Keywords: Acute Coronary Syndrome, Emergency Service, Hospital, Point-of-Care Testing, Troponin I
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