scholarly journals LO61: Test characteristics of high sensitivity troponin T performed at emergency department arrival for acute myocardial infarction in patients with reduced kidney function

CJEM ◽  
2018 ◽  
Vol 20 (S1) ◽  
pp. S28-S28
Author(s):  
A. D. McRae ◽  
S. Vatanpour ◽  
J. Ji ◽  
H. Yang ◽  
D. Southern ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Emergency Department ◽  
Chest Pain ◽  
Troponin T ◽  
High Sensitivity ◽  
Test Characteristics ◽  
High Sensitivity Troponin ◽  
High Sensitivity Troponin T ◽  
Rule Out

Introduction: Patients with chronic kidney disease (CKD) are at high risk of cardiovascular events, and have worse outcomes following acute myocardial infarction (AMI). Cardiac troponin is often elevated in CKD, making the diagnosis of AMI challenging in this population. We sought to quantify test characteristics for AMI of a high-sensitivity troponin T (hsTnT) assay performed at emergency department (ED) arrival in CKD patients with chest pain, and to derive rule-out cutoffs specific to patient subgroups stratified by estimated glomerular filtration rate (eGFR). We also quantified the sensitivity and classification performance of the assays limit of detection (5 ng/L) and the FDA-approved limit of quantitation (6 ng/L) for ruling out AMI at ED arrival. Methods: Consecutive patients in four urban EDs from the 2013 calendar year with suspected cardiac chest pain who had a Roche Elecsys hsTnT assay performed on arrival were included f. This analysis was restricted to patients with an eGFR< 60 ml/min/1.73m2. The primary outcome was 7-day AMI. Secondary outcomes included major adverse cardiac events (death, AMI and revascularization). Test characteristics were calculated and ROC curves were generated for eGFR subgroups. Results: 1416 patients were included. 7-day AMI incidence was 10.1%. 73% of patients had an initial hsTnT concentration greater than the assays 99th percentile (14 ng/L). TCurrently accepted cutoffs to rule out MI at ED arrival ( 5 ng/L and 6 ng/L) had 100% sensitivity for AMI, but no patients with an eGFR less than 30 ml/min/1.73M had hsTnT concentrations below these thresholds. We derived eGFR-adjusted cutoffs to rule out MI with sensitivity >98% at ED arrival, which were able to rule out 6-42% of patients, depending on eGFR category. The proportion of patients able to be accurately ruled-in with a single hsTnT assay was substantially lower among patients with an eGFR <30 ml/min/1.73m2 (6-20% vs 25-43%). We also derived eGFR-adjusted cutoffs to rule-in AMI with specificity >90%, which accurately ruled-in up to 18% of patients. Conclusion: Cutoffs achieving acceptable diagnostic performance for AMI using single hsTnT sampling on ED arrival may have limited clinical utility, particularly among patients with very low eGFR. The ideal diagnostic strategy for AMI in patients with CKD likely involves serial high-sensitivity troponin testing with diagnostic thresholds customized to different eGFR categories.

scholarly journals P101: Sex-specific Troponin T cutoffs for ruling out acute myocardial infarction at ED arrival

CJEM ◽  
2018 ◽  
Vol 20 (S1) ◽  
pp. S92-S92
Author(s):  
A. D. McRae ◽  
M. Graham ◽  
T. Abedin ◽  
J. Ji ◽  
H. Yang ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Chest Pain ◽  
Troponin T ◽  
High Sensitivity ◽  
Diagnostic Sensitivity ◽  
Test Characteristics ◽  
High Sensitivity Troponin ◽  
Specific Rule ◽  
Rule Out

Introduction: ex-specific diagnostic cutoffs may improve the test characteristics of high-sensitivity troponin assays for the diagnosis of myocardial infarction. Sex-specific cutoffs for ruling in MI improve the sensitivity of the assay for MI among women, and improve the specificity of diagnosis among men. We hypothesized that the use of sex-specific high-sensitivity Troponin T (hsTnT) cutoffs for ruling out MI at the time of ED arrival would improve the classification efficiency of the assay by enabling more patients to have MI ruled out at the time of ED arrival while maintaining diagnostic sensitivity. The objective of this study was to quantify the test characteristics of sex-specific cutoffs of an hsTnT assay for acute myocardial infarction (AMI) when performed at ED arrival in patients with chest pain. Methods: This retrospective study included consecutive ED patients with suspected cardiac chest pain evaluated in four urban EDs were, excluding those with ST-elevation AMI, cardiac arrest or abnormal kidney function. The primary outcomes was AMI at 7 days. Secondary outcomes included major adverse cardiac events (MACE: all-cause mortality, AMI and revascularization) and the individual MACE components. We quantified test characteristics (sensitivity, negative predictive value, likelihood ratios and proportion of patients ruled out) for multiple combinations of sex-specific rule-out cutoffs. We calculated net reclassification improvement compared to universal rule-out cutoffs of 5ng/L (the assays limit of detection) and 6ng/L (the FDA-approved limit of quantitation for US laboratories). Results: 7130 patients, including 3931 men and 3199 women, were included. The 7-day incidence of AMI was 7.38% among men and 3.78% among women. Universal cutoffs of 5 and 6 ng/L ruled out AMI with 99.7% sensitivity in 33.6 and 42.2% of patients. The best-performing combination of sex-specific cutoffs (8g/L for men and 6ng/L for men) ruled out AMI with 98.7% sensitivity in 51.9% of patients. Conclusion: Sex-specific hsTnT cutoffs for ruling out AMI at ED arrival may achieve substantial improvement in classification performance, enabling more patients to be ruled out at ED arrival, while maintaining acceptable diagnostic sensitivity for AMI. Universal and sex-specific rule-out cutoffs differ by only small changes in hsTnT concentration. Therefore, these findings should be confirmed in other datasets.

scholarly journals The Use of Very Low Concentrations of High-sensitivity Troponin T to Rule Out Acute Myocardial Infarction Using a Single Blood Test

2016 ◽  
Vol 23 (9) ◽  
pp. 1004-1013 ◽  
Author(s):  
Richard Body ◽  
Christian Mueller ◽  
Evangelos Giannitsis ◽  
Michael Christ ◽  
Jorge Ordonez-Llanos ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Blood Test ◽  
Troponin T ◽  
High Sensitivity ◽  
High Sensitivity Troponin ◽  
Low Concentrations ◽  
High Sensitivity Troponin T ◽  
Rule Out

LO57: Very low concentrations of high-sensitivity troponin T at presentation can rapidly exclude acute myocardial infarction in a significant proportion of ED chest pain patients

CJEM ◽  
2018 ◽  
Vol 20 (S1) ◽  
pp. S26-S27
Author(s):  
J. E. Andruchow ◽  
T. S. Boyne ◽  
S. Vatanpour ◽  
D. Wang ◽  
A. D. McRae
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Chest Pain ◽  
Emergency Physician ◽  
Troponin T ◽  
High Sensitivity ◽  
High Sensitivity Troponin ◽  
Low Concentrations ◽  
High Sensitivity Troponin T ◽  
Pain Patients

Introduction: Chest pain is one of the most common presenting complaints to emergency departments (EDs) across the world, and the exclusion of acute myocardial infarction (AMI) using troponin testing is central to the care of many of these patients. While testing strategies using conventional troponin assays require repeat testing over many hours to avoid missed diagnoses, high-sensitivity troponin (hs-cTn) assays may be able to exclude AMI in a large proportion of patients with a single result at presentation. This objective of this study is to validate the ability of very low concentrations of hs-cTn at presentation to exclude AMI in ED chest pain patients. Methods: This prospective cohort study was conducted at a single urban tertiary center and regional percutaneous coronary intervention site in Calgary, Alberta. Patients were eligible for enrolment if they presented to the ED with chest pain, were 25-years or older and required biomarker testing to rule out AMI at the discretion of the attending emergency physician. Patients were excluded if they had clear acute ischemic ECG changes, new arrhythmia or renal failure requiring hemodialysis. A high-sensitivity troponin result (Roche Elecsys hs-cTnT) was obtained in all patients at presentation. The primary outcome was AMI on the index visit. Secondary outcomes included 30-day AMI and major adverse cardiac events (MACE - including AMI, revascularization or cardiac death). Electronic medical records were reviewed and telephone follow-up was obtained for all patients at 30-days to ensure relevant events were captured. Two physician adjudication (board-certified emergency physician and cardiologist) was obtained for all outcomes. This study was REB approved. Results: A total of 1,167 patients were enrolled from August 2014 September 2016, of which 191 (16.3%) patients had an initial troponin below the limit of blank (LoB, <3 ng/L) and 416 (32.8%) were below the limit of detection (LoD, <5 ng/L). The sensitivity of a single troponin below the LoB (<3 ng/L) for index AMI was 100% (95% CI 96.2%-100%) and for 30-day AMI was 100% (95% CI 96.4-100%). The sensitivity of a troponin below the LoD (<5 ng/L) for index AMI was 97.9% (95% CI 92.7%-99.8%) and for 30-day AMI was 98.0% (95% CI 93.0-99.8%). Sensitivity for 30-day MACE at both cutoffs was lower: 98.4% (95% CI 94.3-99.8%) for <3 ng/L, and 94.4% (95% CI 88.8-97.7%) for <5 ng/L, respectively; however, negative predictive values remained high at both cutoffs: <3 ng/L, 99.0% (95% CI 96.3-99.9%) and <5 ng/L, 98.3% (95% CI 96.6-99.3%). Conclusion: A high sensitivity troponin T result below the LoB (<3 ng/L) is highly sensitive for excluding AMI and identifies patients at low risk of 30-day MACE. A result below the LoB (<5 ng/L) will identify a larger population of patients as low risk but has a greater risk of missed AMI and MACE.

scholarly journals LO04: Very low concentrations of high-sensitivity troponin T at presentation can rapidly exclude acute myocardial infarction in a significant proportion of ED chest pain patients

CJEM ◽  
2017 ◽  
Vol 19 (S1) ◽  
pp. S28
Author(s):  
J. Andruchow ◽  
A. McRae ◽  
T. Abedin ◽  
D. Wang ◽  
E. Lang ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Chest Pain ◽  
Limit Of Detection ◽  
Troponin T ◽  
High Sensitivity ◽  
High Sensitivity Troponin ◽  
Low Concentrations ◽  
High Sensitivity Troponin T ◽  
Pain Patients

Introduction: Chest pain is one of the most common presenting complaints to emergency departments (EDs) across the world, and the exclusion of acute myocardial infarction (AMI) using troponin testing is central to the care of many of these patients. Testing strategies using conventional troponin assays require repeat testing over many hours to avoid missed diagnoses. This study aims to validate the ability of very low concentrations of troponin at presentation to exclude AMI in ED chest pain patients. Methods: This prospective cohort study was conducted at a single urban tertiary centre and regional percutaneous coronary intervention site in Calgary, Alberta. Patients were eligible for enrolment if they presented to the ED with chest pain, were 25-years or older and required biomarker testing to rule out AMI at the discretion of the attending emergency physician. Patients were excluded if they had clear acute ischemic ECG changes, new arrhythmia or renal failure requiring hemodialysis. High-sensitivity troponin-T (Roche Elecsys hs-cTnT) results were obtained in all patients at presentation. Relevant outcomes were obtained from administrative data. The primary outcome was AMI within 30-days of ED visit, the secondary outcome was 30-day major adverse cardiac events (MACE). The study was REB approved. Results: A total of 1,016 patients were enrolled from August 2014-September 2016, of which 174 (17.1%) patients had an initial troponin below the limit of blank (&lt;3 ng/L) and 369 (36.3%) had a level below the limit of detection (&lt;5 ng/L). The sensitivity and negative predictive value (NPV) of a troponin below limit of blank (&lt;3 ng/L) for 30-day AMI were 100% (95% CI 89.3%-100%) and 100% (95% CI 97.8-100%), respectively. The sensitivity and NPV of a troponin below limit of detection (&lt;5 ng/L) for 30-day AMI were 93.8% (95% CI 80.0-98.3%) and 99.5% (95% CI 98.1-99.9%) respectively. Sensitivity for 30-day MACE at both cutoffs was lower: 96.1% (95% CI 92.5-98.0%) for &lt;3 ng/L, and 88.4% (95% CI 83.3-92.1%) for &lt;5 ng/L, respectively. Conclusion: A high sensitivity troponin T result below the limit of blank is highly sensitive at excluding AMI and identifies patients at reasonably low risk of 30-day MACE. A result below the limit of detection will identify a larger population of patients as low risk but has a greater risk of missed AMI and MACE.

High-sensitivity troponin T for early rule-out of myocardial infarction in recent onset chest pain

2011 ◽  
Vol 29 (10) ◽  
pp. 805-810 ◽  
Author(s):  
Sally Aldous ◽  
Chris Pemberton ◽  
A Mark Richards ◽  
Richard Troughton ◽  
Martin Than
Keyword(s):  
Myocardial Infarction ◽  
Chest Pain ◽  
Troponin T ◽  
High Sensitivity ◽  
Recent Onset ◽  
High Sensitivity Troponin ◽  
High Sensitivity Troponin T ◽  
Rule Out
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