Abstract
Objective Chest pain, a common emergency department presentation, requires rapid evaluation. The current standard of care is clinical evaluation, serial troponin measurements, and electrocardiograms. However, an optical technology-based noninvasive wearable device, the Infrasensor, which can rapidly and transcutaneously assess cardiac troponin I (cTnI), was recently developed. We aimed to evaluate the Infrasensor performance in cTnI-defined cohorts. Methods This was a 10-hospital prospective observational study in healthy US subjects with a normal cTnI and in patients with an elevated cTnI. Healthy subjects, determined by a negative questionnaire and bloodwork, underwent 3-minute Infrasensor measurement and measures of high-sensitivity cTnI. Elevated cTnI patients had the same evaluations. Using a fivefold cross-validation technique, cTnI-based binary classification models with/without age were trained on 80%, and validated on 20%, of the dataset (n=168, elevated cTnI equally partitioned into five similar sized subsets). Results Of 840 enrolled, 727 (86.5%) had nonelevated and 113 had elevated cTnI. Median age was 61 years (interquartile range, 52-71 years) for the elevated cohort and 48 years (interquartile range, 32-57 years) for the nonelevated. Overall, 416 (50.5%) were female, with 33 of 113 (29.2%) in the elevated cohort and 383 of 727 (52.7%) in the nonelevated cohort. The sensitivity, specificity, and the negative and positive predictive values of the Infrasensor for identifying elevated cTnI were 0.90, 0.70, 0.98, and 0.48, respectively, with a C-statistic of 0.90 (95% confidence interval, 0.89-0.99). Conclusion The Infrasensor accurately identifies elevated cTnI within 3 minutes of application.