A novel troponin I rule-out value below the upper reference limit for acute myocardial infarction

High-Sensitivity Cardiac Troponin I Levels Below 99th Percentile Upper Reference Limit in Patients Presenting with Suspicion of Acute Coronary Syndrome (ACS) in Emergency Department at a Tertiary Care Hospital in Karachi, Pakistan

INTRODUCTION

Troponin I levels are biomarkers of choice for diagnosis of acute myocardial infarction (AMI). However, prognostic significance of values below the 99th percentile upper reference limit (URL) in patients presenting with symptoms suggestive of Acute coronary syndrome (ACS) need further evaluation.

AIM

The objectives of the study were to find the association of High sensitivity (hs)-Troponin I values below 99th percentile URL with age and the Emergency Department (ED) outcome, to determine single cut-off for safe discharge of these patients from the ED and to determine the 30-day outcome of the patients admitted under cardiac speciality.

METHODS

This is a retrospective study of patients presenting with suspicion of ACS in the ED between January 2019 till April 2021 and hs-Troponin I values below 99th percentile URL.

RESULTS

Among 15,441 patients, 8034 (52%) were males and 7407 (48%) were females. 9677 (63%) of the patients had hs-Troponin I values < 5 ng/L while 5764 (37%) had values between 5 ng/L and 99th percentile URL. Higher hs-Troponin I values were associated with a worse ED outcome. Serial troponin I levels were performed in only 2.4% of the cohort. Receiver operating characteristics for ACS demonstrated an AUC of 0.84 at a cut off value of 12.75 ng/L, with sensitivity (76.9%) and specificity was 75.1%. The 30-day outcome of the patients admitted under cardiac speciality revealed no mortality in either group.

CONCLUSION

An overall single cut-off value of 12.75 ng/L can be used in our population for ruling our ACS provided it is unaccompanied by other supportive clinical and ECG findings.

High-sensitivity troponin assays for early rule-out of acute myocardial infarction in people with acute chest pain: a systematic review and economic evaluation

BACKGROUND

Early diagnosis of acute myocardial infarction is important, but only 20% of emergency admissions for chest pain will actually have an acute myocardial infarction. High-sensitivity cardiac troponin assays may allow rapid rule out of myocardial infarction and avoid unnecessary hospital admissions.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of high-sensitivity cardiac troponin assays for the management of adults presenting with acute chest pain, in particular for the early rule-out of acute myocardial infarction.

METHODS

Sixteen databases were searched up to September 2019. Review methods followed published guidelines. Studies were assessed for quality using appropriate risk-of-bias tools. The bivariate model was used to estimate summary sensitivity and specificity for meta-analyses involving four or more studies; otherwise, random-effects logistic regression was used. The health economic analysis considered the long-term costs and quality-adjusted life-years associated with different troponin testing methods. The de novo model consisted of a decision tree and a state-transition cohort model. A lifetime time horizon (of 60 years) was used.

RESULTS

Thirty-seven studies (123 publications) were included in the review. The high-sensitivity cardiac troponin test strategies evaluated are defined by the combination of four factors (i.e. assay, number and timing of tests, and threshold concentration), resulting in a large number of possible combinations. Clinical opinion indicated a minimum clinically acceptable sensitivity of 97%. When considering single test strategies, only those using a threshold at or near to the limit of detection for the assay, in a sample taken at presentation, met the minimum clinically acceptable sensitivity criterion. The majority of the multiple test strategies that met this criterion comprised an initial rule-out step, based on high-sensitivity cardiac troponin levels in a sample taken on presentation and a minimum symptom duration, and a second stage for patients not meeting the initial rule-out criteria, based on presentation levels of high-sensitivity cardiac troponin and absolute change after 1, 2 or 3 hours. Two large cluster randomised controlled trials found that implementation of an early rule-out pathway for myocardial infarction reduced length of stay and rate of hospital admission without increasing cardiac events. In the base-case analysis, standard troponin testing was both the most effective and the most costly. Other testing strategies with a sensitivity of 100% (subject to uncertainty) were almost equally effective, resulting in the same life-year and quality-adjusted life-year gain at up to four decimal places. Comparisons based on the next best alternative showed that for willingness-to-pay values below £8455 per quality-adjusted life-year, the Access High Sensitivity Troponin I (Beckman Coulter, Brea, CA, USA) [(symptoms > 3 hours AND < 4 ng/l at 0 hours) OR (< 5 ng/l AND Δ < 5 ng/l at 0 to 2 hours)] would be cost-effective. For thresholds between £8455 and £20,190 per quality-adjusted life-year, the Elecsys® Troponin-T high sensitive (Roche, Basel, Switzerland) (< 12 ng/l at 0 hours AND Δ < 3 ng/l at 0 to 1 hours) would be cost-effective. For a threshold > £20,190 per quality-adjusted life-year, the Dimension Vista® High-Sensitivity Troponin I (Siemens Healthcare, Erlangen, Germany) (< 5 ng/l at 0 hours AND Δ < 2 ng/l at 0 to 1 hours) would be cost-effective.

CONCLUSIONS

High-sensitivity cardiac troponin testing may be cost-effective compared with standard troponin testing.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019154716.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 25, No. 33. See the NIHR Journals Library website for further project information.

Myocardial Injury in Critically Ill Patients with Community-acquired Pneumonia. A Cohort Study

Rationale: Myocardial injury, as reflected by elevated cardiac troponin levels in plasma, is common in patients with community-acquired pneumonia (CAP), but its temporal dynamics and etiology remain unknown. Objectives: Our aim was to determine the incidence of troponin release in patients with CAP and identify risk factors that may point to underlying etiologic mechanisms. Methods: We included consecutive patients admitted with severe CAP to two intensive care units in the Netherlands between 2011 and 2015. High-sensitivity cardiac troponin I was measured daily during the first week. We used multivariable linear regression to identify variables associated with troponin release on admission, and we used mixed-effects regression to model the daily rise and fall of troponin levels over time. Results: Of 200 eligible patients, 179 were included, yielding 792 observation days. A total of 152 (85%) patients developed raised troponin levels greater than 26 ng/L. Baseline factors independently associated with troponin release included coronary artery disease (176% increase; 95% confidence interval [CI], 11-589), smoking (248% increase; 95% CI, 33-809), and higher Acute Physiology and Chronic Health Evaluation IV score (2% increase; 95% CI, 0.8-3.3), whereas Staphylococcus aureus as a causative pathogen was protective (70% reduction; 95% CI, 18-89). Time-dependent risk factors independently associated with daily increase in troponin concentrations included reduced platelet count (2.3% increase; 95% CI, 0.6-4), tachycardia (1.5% increase; 95% CI, 0.1-2.9), hypotension (6.2% increase; 95% CI, 2.1-10.6), dobutamine use (44% increase; 95% CI, 12-85), prothrombin time (8.2% increase; 95% CI, 0.2-16.9), white cell count (1.7% increase; 95% CI, 0-3.5), and fever (22.7% increase; 95% CI, 0.1-49.6). Conclusions: Cardiac injury develops in a majority of patients with severe CAP. Myocardial oxygen supply-demand mismatch and activated inflammation/coagulation are associated with this injury. Clinical trial registered with www.clinicaltrials.gov (NCT01905033).

Serial high-sensitivity cardiac troponin T measurements to rule out acute myocardial infarction and a single high baseline measurement for swift rule-in: A systematic review and meta-analysis

Aims:

The purpose of this study was to determine (a) the ability of serial high-sensitivity cardiac troponin T measurements to rule out acute myocardial infarction and (b) the ability of a single high baseline high-sensitivity cardiac troponin T measurement to rule in acute myocardial infarction in patients presenting to the emergency department with acute chest pain.

Methods and results:

Embase, Medline, Cochrane, Web of Science and Google scholar were searched for prospective cohort studies that evaluated parameters of diagnostic accuracy of serial high-sensitivity cardiac troponin T to rule out acute myocardial infarction and a single baseline high-sensitivity cardiac troponin T value>50 ng/l to rule in acute myocardial infarction. The search yielded 21 studies for the systematic review, of which 14 were included in the meta-analysis, with a total of 11,929 patients and an overall prevalence of acute myocardial infarction of 13.0%. For rule-out, six studies presented the sensitivity of serial measurements <14 ng/l. This cut-off classified 60.1% of patients as rule-out and the summary sensitivity was 96.7% (95% confidence interval: 92.3–99.3). Three studies presented the sensitivity of a one-hour algorithm with a baseline high-sensitivity cardiac troponin T value<12 ng/l and delta 1 hour <3 ng/l. This algorithm classified 60.2% of patients as rule-out and the summary sensitivity was 98.9% (96.4–100). For rule-in, six studies reported the specificity of baseline high-sensitivity cardiac troponin T value>50 ng/l. The summary specificity was 94.6% (91.5–97.1).

Conclusion:

Serial high-sensitivity cardiac troponin T measurement strategies to rule out acute myocardial infarction perform well, and a single baseline high-sensitivity cardiac troponin T value>50 ng/l to rule in acute myocardial infarction has a high specificity.

High-Sensitivity Cardiac Troponin and the Risk Stratification of Patients With Renal Impairment Presenting With Suspected Acute Coronary Syndrome

BACKGROUND

High-sensitivity cardiac troponin testing may improve the risk stratification and diagnosis of myocardial infarction, but concentrations can be challenging to interpret in patients with renal impairment, and the effectiveness of testing in this group is uncertain.

METHODS

In a prospective multicenter study of consecutive patients with suspected acute coronary syndrome, we evaluated the performance of high-sensitivity cardiac troponin I in those with and without renal impairment (estimated glomerular filtration rate <60mL/min/1.73m2). The negative predictive value and sensitivity of troponin concentrations below the risk stratification threshold (5 ng/L) at presentation were reported for a primary outcome of index type 1 myocardial infarction, or type 1 myocardial infarction or cardiac death at 30 days. The positive predictive value and specificity at the 99th centile diagnostic threshold (16 ng/L in women, 34 ng/L in men) was determined for index type 1 myocardial infarction. Subsequent type 1 myocardial infarction and cardiac death were reported at 1 year.

RESULTS

Of 4726 patients identified, 904 (19%) had renal impairment. Troponin concentrations <5 ng/L at presentation identified 17% of patients with renal impairment as low risk for the primary outcome (negative predictive value, 98.4%; 95% confidence interval [CI], 96.0%-99.7%; sensitivity 98.9%; 95%CI, 97.5%-99.9%), in comparison with 56% without renal impairment (P<0.001) with similar performance (negative predictive value, 99.7%; 95% CI, 99.4%-99.9%; sensitivity 98.4%; 95% CI, 97.2%-99.4%). The positive predictive value and specificity at the 99th centile were lower in patients with renal impairment at 50.0% (95% CI, 45.2%-54.8%) and 70.9% (95% CI, 67.5%-74.2%), respectively, in comparison with 62.4% (95% CI, 58.8%-65.9%) and 92.1% (95% CI, 91.2%-93.0%) in those without. At 1 year, patients with troponin concentrations >99th centile and renal impairment were at greater risk of subsequent myocardial infarction or cardiac death than those with normal renal function (24% versus 10%; adjusted hazard ratio, 2.19; 95% CI, 1.54-3.11).

CONCLUSIONS

In suspected acute coronary syndrome, high-sensitivity cardiac troponin identified fewer patients with renal impairment as low risk and more as high risk, but with lower specificity for type 1 myocardial infarction. Irrespective of diagnosis, patients with renal impairment and elevated cardiac troponin concentrations had a 2-fold greater risk of a major cardiac event than those with normal renal function, and should be considered for further investigation and treatment.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01852123.

Association of High-Sensitivity Cardiac Troponin I Concentration With Cardiac Outcomes in Patients With Suspected Acute Coronary Syndrome

Importance

High-sensitivity cardiac troponin I testing is widely used to evaluate patients with suspected acute coronary syndrome. A cardiac troponin concentration of less than 5 ng/L identifies patients at presentation as low risk, but the optimal threshold is uncertain.

Objective

To evaluate the performance of a cardiac troponin I threshold of 5 ng/L at presentation as a risk stratification tool in patients with suspected acute coronary syndrome.

Data Sources

Systematic search of MEDLINE, EMBASE, Cochrane, and Web of Science databases from January 1, 2006, to March 18, 2017.

Study Selection

Prospective studies measuring high-sensitivity cardiac troponin I concentrations in patients with suspected acute coronary syndrome in which the diagnosis was adjudicated according to the universal definition of myocardial infarction.

Data Extraction and Synthesis

The systematic review identified 19 cohorts. Individual patient-level data were obtained from the corresponding authors of 17 cohorts, with aggregate data from 2 cohorts. Meta-estimates for primary and secondary outcomes were derived using a binomial-normal random-effects model.

Main Outcomes and Measures

The primary outcome was myocardial infarction or cardiac death at 30 days. Performance was evaluated in subgroups and across a range of troponin concentrations (2-16 ng/L) using individual patient data.

Results

Of 11 845 articles identified, 104 underwent full-text review, and 19 cohorts from 9 countries were included. Among 22 457 patients included in the meta-analysis (mean age, 62 [SD, 15.5] years; n = 9329 women [41.5%]), the primary outcome occurred in 2786 (12.4%). Cardiac troponin I concentrations were less than 5 ng/L at presentation in 11 012 patients (49%), in whom there were 60 missed index or 30-day events (59 index myocardial infarctions, 1 myocardial infarction at 30 days, and no cardiac deaths at 30 days). This resulted in a negative predictive value of 99.5% (95% CI, 99.3%-99.6%) for the primary outcome. There were no cardiac deaths at 30 days and 7 (0.1%) at 1 year, with a negative predictive value of 99.9% (95% CI, 99.7%-99.9%) for cardiac death.

Conclusions and Relevance

Among patients with suspected acute coronary syndrome, a high-sensitivity cardiac troponin I concentration of less than 5 ng/L identified those at low risk of myocardial infarction or cardiac death within 30 days. Further research is needed to understand the clinical utility and cost-effectiveness of this approach to risk stratification.