Utility of Absolute and Relative Changes in Cardiac Troponin Concentrations in the Early Diagnosis of Acute Myocardial Infarction

Abstract

Background-Current guidelines for the diagnosis of acute myocardial infarction (AMI), among other criteria, also require a rise and/or fall in cardiac troponin (cTn) levels. It is unknown whether absolute or relative changes in cTn have higher diagnostic accuracy and should therefore be preferred. Methods and Results-In a prospective, observational, multicenter study, we analyzed the diagnostic accuracy of absolute (⌬) and relative (⌬%) changes in cTn in 836 patients presenting to the emergency department with symptoms suggestive of AMI. Blood samples for the determination of high-sensitive cTn T and cTn I ultra were collected at presentation and after 1 and 2 hours in a blinded fashion. The final diagnosis was adjudicated by 2 independent cardiologists. The area under the receiver operating characteristic curve for diagnosing AMI was significantly higher for 2-hour absolute 001).The receiver operating characteristic curve-derived cutoff value for 2-hour absolute (⌬) change was 0.007 g/L for high-sensitivity cTn T and 0.020 g/L for cTn I ultra (both cutoff levels are half of the 99th percentile of the respective cTn assay). Absolute changes were superior to relative changes in patients with both low and elevated baseline cTn levels. Conclusions-Absolute changes of cTn levels have a significantly higher diagnostic accuracy for AMI than relative changes, and seem therefore to be the preferred criteria to distinguish AMI from other causes of cTn elevations. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00470587.

Prospective validation of a 1-hour algorithm to rule-out and rule-in acute myocardial infarction using a high-sensitivity cardiac troponin T assay

“…11 This algorithm is based on 2 concepts. First, high-sensitivity cardiac troponin T is interpreted as a quantitative variable where the proportion of patients who have acute MI increases with increasing concentrations of cardiac troponin T. [6][7][8][9][10][11][12][13][14][15] Second, early absolute changes in the concentrations within 1 hour provide incremental diagnostic information when added to baseline levels, with the combination acting as a reliable surrogate for late concentrations at 3 or 6 hours. [6][7][8][9][10][11][12][13][14][15] However, many experts remained skeptical regarding the safety of the highsensitivity cardiac troponin T 1-hour algorithm and its wider applicability.…”

“…The adjudication also included later levels of high-sensitivity cardiac troponin T to take advantage of the higher sensi-tivity and higher overall diagnostic accuracy offered by these assays. [7][8][9][10][11][12][13][14][15] This allowed the additional detection of small acute MIs that would be missed by the adjudication based on conventional cardiac troponin assays. Two independent cardiologists reviewed all available medical records pertaining to the patient from the time of emergency department presentation to 90-day follow-up.…”

“…Selection of these 2 parameters was based on the previously published very high diagnostic accuracy of their combination. 14,18 For rule-out of acute MI, the criterion was defined as a baseline high-sensitivity cardiac troponin T level of less than 12 ng/L and an absolute change within the first hour of less than 3 ng/L. For rule-in of acute MI, the criterion was defined as either a baseline high-sensitivity cardiac troponin T value of 52 ng/L or greater, or an absolute change within the first hour of 5 ng/L or greater.…”

“…Major advances have recently been achieved by the development of more sensitive cardiac troponin assays. [6][7][8][9][10][11][12][13][14][15] High-sensitivity cardiac troponin assays, which allow measurement of even low concentrations of cardiac troponin with high precision, have been shown to largely overcome the sensitivity deficit of conventional cardiac troponin assays within the first hours of presentation in the diagnosis of acute MI. [6][7][8][9][10][11][12][13][14][15] These studies have consistently shown that the classic diagnostic interpretation of cardiac troponin as a dichotomous variable (troponinnegative and troponin-positive) no longer seems appropriate, because the positive predictive value for acute MI of being troponin-positive was only about 50%.…”

“…[6][7][8][9][10][11][12][13][14][15] High-sensitivity cardiac troponin assays, which allow measurement of even low concentrations of cardiac troponin with high precision, have been shown to largely overcome the sensitivity deficit of conventional cardiac troponin assays within the first hours of presentation in the diagnosis of acute MI. [6][7][8][9][10][11][12][13][14][15] These studies have consistently shown that the classic diagnostic interpretation of cardiac troponin as a dichotomous variable (troponinnegative and troponin-positive) no longer seems appropriate, because the positive predictive value for acute MI of being troponin-positive was only about 50%. [6][7][8][9][10][11][12][13][14][15] The best way to interpret and Prospective validation of a 1-hour algorithm to rule-out and rule-in acute myocardial infarction using a high-sensitivity cardiac troponin T assay Background: We aimed to prospectively valid ate a novel 1hour algorithm using high sensitivity cardiac troponin T measurement for early ruleout and rulein of acute myocardial infarction (MI).…”