17 Jul Single Measurement of High-Sensitivity Troponin To Assess Myocardial Infarction Risk
MedicalResearch.com Interview with:
Dr. Fred Apple, PhD, DABCC
Medical director,Clinical Laboratories, Clinical Chemistry, Clinical and Forensic Toxicology and Point of Care Testing, Hennepin HealthCare
Principal investigator, Minneapolis Medical Research Foundation
Professor, Department of Laboratory Medicine and Pathology
University of Minnesota
MedicalResearch.com: What is the background for this study?
Response: Few studies have addressed the role of high sensitivity cardiac troponin (hs-cTn) assays in ruling out myocardial infarction (MI) based on the measurement of a single baseline specimen in US patients presenting to the emergency department with symptoms suggestive of ischemia. Most studies have been published predicated on patients in Europe, Australia, and New Zealand. As US emergency departments have different ordering practices for using cTn in triaging patients, it is important to validate the role of hs-cTn assays in US practices to assure providers of appropriate utilization. We have published two papers using the Abbott ARCHITECT hs-cTnI assay, the same one used outside the US in clinical practice (as this assay is not yet FDA cleared) in a US cohort (clinicialtrials.gov trial: UTROPIA – Sandoval Y, Smith SW, Shah ASV, Anand A, Chapman AR, Love SA, Schulz K, Cao J, Mills NL, Apple FS. Rapid rule-out of acute myocardial injury using a single high-sensitivity cardiac troponin I measurement. Clin Chem 2017;63:369-76. Sandoval Y, Smith SW, Love SA, Sexter A, Schulz K, Apple FS. Single high-sensitivity cardiac troponin I to rule out myocardial infarction. Am J Med 2017;130:1076-1083) that have shown similar rule out capacities predicated on clinical presentation, a normal ECG and the role of hs-cTnI testing.
MedicalResearch.com: What are the main findings?
Response: The current JACC study demonstrates for the first time in US emergency departments, in a multi-center patient cohort (HIGH-US) predicated on 2 FDA cleared hs-cTnI assays (Siemens Healthineers Atellica IM and ADVIA Centaur) that using both the limit of detection (LoD) and an optimized threshold (< 5 ng/L) for both assays that 1) approximately 50% of patients were identified as low risk at presentation, 2) <1% of patients had an index MI and 3) that < 1 -2% of patients were at high risk of MI or death at 30-days (sensitivities 98.6%, negative predicative value (NPV) 99.6%.)
Further for high risk patients, hs-cTnI baseline results at >120 ng/L resulted in positive predictive values (PPV) of >70%; identifying approximately 10% of patients as high-risk, with 7 of 10 MIs identified.
Overall approximately 60% of patients presenting with suspected MI can be triaged using a single hs-cTnI at presentation.
MedicalResearch.com: What should readers take away from your report?
Response: Not all hs-cTnI and hs-cTnT assays are the same, and each hs-assay used in practice needs to be validated both analytically (LoD, imprecisions at threshold concentrations, sex-specific 99th percentile upper reference limits [URLs]) and clinically (role of baseline symptoms, ECG, and hs-cTn results) as US patient presentations often differ than the rest of the world and often utilized differently by US providers. The time for laboratory medicine to transition to hs-assays is now, but does require a partnership with emergency medicine and clinical medicine /cardiology to establish new practice patterns; with the understanding that cTn is not a stand-alone test; but offers powerful rule out and rule in diagnostics and continuous risk assessment very early in a patient’s presentation. The projected cost savings to health care systems, with the ability for early rule out/early discharge to out-patient follow-up as well as early triage for high risk patient to hopefully improve short and long term outcomes, will be substantial.
MedicalResearch.com: What recommendations do you have for future research as a result of this work?
Response: With new hs-cTn assays being cleared by the FDA for clinical use in the US, additional focus on the use of sex-specific URLs to optimize better care in women predicated on lower 99th percentiles and in patients with renal disease will be two important areas to study.
Disclosures listed in JACC article.
Myocardial Infarction Risk Stratification With a Single Measurement of High-Sensitivity Troponin I Yader Sandoval, Richard Nowak, Christopher R. deFilippi, Robert H.Christenson, W. Frank Peacock, James McCord, Alexander T. Limkakeng, AnneSexter, Fred S. Apple
Journal of the American College of CardiologyJul 2019, 74 (3) 271-282; DOI: 10.1016/j.jacc.2019.05.058
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