Search

Aims: First, describe how acute myocardial infarction criteria are used to diagnose type 1 (T1MI) and 2 (T2MI) myocardial infarction. Second, determine whether subjective or objective criteria are used for T2MI. Third, examine outcomes for T2MI based on the presence or absence of objective evidence of myocardial ischemia compared with myocardial injury.Methods and results: Post-hoc analysis of UTROPIA (NCT02060760), a prospective, observational, cohort study involving 1640 consecutive emergency department patients with serial high-sensitivity cardiac troponin I among whom 74 (4.5%) had T1MI, 103 (6.3%) T2MI, and 245 (15%) myocardial injury. Compared with T1MI, patients with T2MI were less likely to have ischemic symptoms (97% vs. 83%), Q waves (24% vs. 1%), new ST-T wave changes (74% vs. 51%), new regional wall motion abnormality (64% vs. 11%), and a culprit lesion on coronary angiography (59% vs. 0%) (all p<0.05). T2MIs were more likely to be diagnosed using subjective criteria (symptoms alone) than T1MI (42% vs. 12%, p<0.0001). Patients with objective T2MI, but not subjective T2MI, had a two-fold increase in early mortality compared with myocardial injury, with 30- and 60-day hazard ratios (95% confidence interval) of 2.3 (0.9, 6.2) and 2.0 (0.9, 4.7) respectively.Conclusions: Among patients with T2MI, many cases are diagnosed using subjective criteria. The presence of objective evidence of myocardial ischemia may identify a higher-risk group of T2MI patients in whom early outcomes are worse than myocardial injury. Emphasis on using objective evidence of myocardial ischemia to diagnose T2MI may result in a more precise and specific disease definition.

Introduction:Using high-sensitivity cardiac troponin (hs-cTn) I and T assays, various strategies have been developed to expedite the evaluation of patients with suspected acute myocardial infarction (AMI). Whether such approaches are superior to the standard of care involving the use of 12-lead electrocardiography (ECG) and serial cTn below the 99thpercentile upper-reference limit (URL) is uncertain.Objective:Compare the diagnostic and prognostic performance of strategies involving 0- and 3-hour (h) hs-cTnI testing to rule-out AMI.Methods:Post-hoc analysis of the Use of Troponin in ACS (UTROPIA) study (NCT02060760); a prospective US-based study of consecutive, unselected ED patients in whom serial (0/3h) cTnI was obtained on clinical indication and hs-cTnI (Abbott, investigational) measured; 99thURLs: F 16 ng/L, M 34 ng/L. We compared the diagnostic (index AMI) and prognostic (AMI or death at 30-days) performance of three distinct rule-out pathways involving 0- and/or 3-h hs-cTnI testing: a) European Society of Cardiology (ESC), b) High-STEACS, and c) serial testing <99thpercentile (classic) in a UTROPIA patient subset with established symptom onset.Results:Among 582 patients, 70 (12%) had AMI. Prognostic sensitivities (95% CI) and percent eligible for rule-out using hs-cTnI alone without ECG: a) classic: 93% (87.0-98.9) and 77%, b) ESC: 70.4% (59.8-81.0) and 86%, and c) High-STEACS: 93% (87.0-98.9) and 68%. Prognostic sensitivities and percent eligible for rule-out using hs-cTnI alone with ECG: a) classic: 100% (94.9-100) and 33%, b) ESC: 94.4% (89.0-99.7) and 35%, and c) High-STEACS: 100% (94.9-100) and 30%.Conclusions:Our study demonstrates that 0/3h pathways, in particular the ESC model, result in unacceptably low diagnostic and prognostic sensitivities when used in isolation without ECG findings. For ruling-out, both the classic and High-STEACS, but not the ESC, pathways have excellent diagnostic and prognostic performance. Our findings showing similar rule-out performance for the classic approach indicate that the standard-of-care approach involving a non-ischemic ECG and serial hs-cTnI <99thsex-specific URL is safe, efficient, and potentially more attractive to clinicians because of its simplicity.

Introduction:Limited data exists on early cardiac troponin (cTn) concentrations and timing of increases above 99thpercentile upper reference limits (URL) in relation to symptom onset in non-ST-segment elevation myocardial infarction (NSTEMI). We examined kinetics of high-sensitivity (hs) cTn concentrations on serial testing in the initial 6-hour time period following symptom onset in patients presenting to the emergency department (ED) with NSTEMI.Hypothesis:Substantial increases of hs-cTn occur very early in patients with NSTEMI.Methods:Multicenter NSTEMI cohort including 514 patients using hs-cTnI (Abbott) (65% male; age 67y [SD 13]) and 183 patients using hs-cTnT (Roche) (75% male; age 67y [SD 11]) from 7 cohorts (UTROPIA, High-STEACS, RING, ROMI, EDACS, ADAPTCH, SPACE) combined to analyze concentrations measured in the ED within 6 hours of initiation of symptoms. Concentrations (ng/L) plotted against time determined the magnitude and range of serial kinetics using sex-specific and overall URLs. Medians were compared with Kruskal-Wallis test and proportions compared via Chi-Square.Results:For hs-cTnI and hs-cTnT the median time from symptom onset to first draw was 3.1h and 3.5h, respectively. Time to the first increased concentration was longer in males v. females (hs-cTnI 3.7h v. 3.3h (P=0.07); hs-cTnT 3.7h v. 3.4h (P=0.58). Using sex-specific URLs, the proportion of patients with increased concentration at the first blood draw was higher for females v. males (hs-cTnI: 75% v. 62% p=0.002; hs-cTnT: 91% v. 77%; P=0.037) The maximum cTn concentration was greater in males compared to females for hs-cTnI (median=98 ng/L, range 1.9-50,000 ng/L v. median=72 ng/L, range 1.0-11,367 ng/L, P=0.08) and hs-cTnT (median=53, range 4.4-2,842 ng/L v. median=80 ng/L, range 11.8-518 ng/L, P=0.08).Conclusions:In a large NSTEMI population presenting to the ED within 6-hours of symptoms, we demonstrate a) significant variations in hs-cTn concentrations between males and females and b) high percentages of hs-cTn increases above URLs, females > males. Early hs-cTnI and hs-cTnT kinetics vary considerably from classical patterns shown in textbooks, with an improved clinical understanding that early, increased cTn concentrations do occur in NSTEMI.