ISSN 2996-8215
International Journal of Cardiology | Vol. 7, No. 7, July 2016 | pp. 49–56
DOI: 10.46882/2016/IJC/000088
Original Research Article
Diagnostic Utility of High-Sensitivity Cardiac Troponin T 0-Hour/2-Hour Accelerated Protocol for Early Rule-Out of Acute Myocardial Infarction
Chloe Bennett¹, Thomas Wright¹, Oliver Harrison²
¹Emergency Department, St Vincent's Hospital, Sydney, New South Wales, Australia
²School of Medicine, University of Queensland, Brisbane, Queensland, Australia
Abstract:
Rapid, reliable exclusion of acute myocardial infarction (AMI) in patients presenting to the emergency department (ED) with chest pain is vital for optimizing hospital throughput and emergency resource utilization. High-sensitivity cardiac troponin T (hs-cTnT) assays allow for lower limits of detection but require clinically safe diagnostic protocols to prevent a loss of specificity. This prospective study evaluated the diagnostic performance of an accelerated 0-hour/2-hour diagnostic protocol incorporating hs-cTnT for rapid AMI exclusion. We enrolled 412 consecutive patients presenting to the ED with acute chest pain suggestive of an acute coronary syndrome. Blood samples for hs-cTnT quantification were drawn at presentation (0h) and exactly 2 hours later. The final diagnosis of AMI was adjudicated by an independent consensus committee using the universal definition. AMI was diagnosed in 58 patients (14.1%). A baseline presentation hs-cTnT level below 5 ng/L combined with an absolute change less than 3 ng/L within 2 hours successfully ruled out AMI in 57.8% of the cohort. This accelerated 0h/2h protocol yielded a diagnostic sensitivity of 98.3% (95% CI: 90.8%–99.9%) and an exceptional negative predictive value (NPV) of 99.6% (95% CI: 97.7%–99.9%). The diagnostic specificity and positive predictive value (PPV) were 66.7% and 32.6%, respectively. No patient classified as safe for early rule-out experienced an un-adjudicated cardiac event within a 30-day safety follow-up. An accelerated 0h/2h diagnostic protocol incorporating hs-cTnT assays allows for rapid, exceptionally safe exclusion of acute myocardial infarction in over half of presenting ED chest pain patients.
Keywords: High-sensitivity cardiac troponin T, Acute myocardial infarction, Emergency department, Chest pain, Accelerated diagnostic protocol, Negative predictive value
Received: April 05, 2016; Revised: May 18, 2016; Accepted: June 10, 2016; Published: July 22, 2016