An algorithm for rule-in and rule-out of acute myocardial infarction using a novel troponin I assay

Serial high-sensitivity cardiac troponin testing for the diagnosis of myocardial infarction: a scoping review

OBJECTIVES

We aimed to assess the diversity and practices of existing studies on several assays and algorithms for serial measurements of high-sensitivity cardiac troponin (hs-cTn) for risk stratification and the diagnosis of myocardial infarction (MI) and 30-day outcomes in patients suspected of having non-ST-segment elevation MI (NSTEMI).

METHODS

We searched multiple databases including MEDLINE, EMBASE, Science Citation Index, the Cochrane Database of Systematic Reviews and the CENTRAL databases for studies published between January 2006 and November 2021. Studies that assessed the diagnostic accuracy of serial hs-cTn testing in patients suspected of having NSTEMI in the emergency department (ED) were eligible. Data were analysed using the scoping review method.

RESULTS

We included 86 publications, mainly from research centres in Europe, North America and Australasia. Two hs-cTn assays, manufactured by Abbott (43/86) and Roche (53/86), dominated the evaluations. The studies most commonly measured the concentrations of hs-cTn at two time points, at presentation and a few hours thereafter, to assess the two-strata or three-strata algorithm for diagnosing or ruling out MI. Although data from 83 studies (97%) were prospectively collected, 0%-90% of the eligible patients were excluded from the analysis due to missing blood samples or the lack of a final diagnosis in 53 studies (62%) that reported relevant data. Only 19 studies (22%) reported on head-to-head comparisons of alternative assays.

CONCLUSION

Evidence on the accuracy of serial hs-cTn testing was largely derived from selected research institutions and relied on two specific assays. The proportions of the eligible patients excluded from the study raise concerns about directly applying the study findings to clinical practice in frontline EDs.

PROSPERO REGISTRATION NUMBER

CRD42018106379.

Initial experience regarding the safety and yield of rest-stress myocardial perfusion imaging in emergency department patients with mildly abnormal high-sensitivity cardiac troponins

BACKGROUND

With high-sensitivity troponin testing, approximately a third of patients presenting to emergency departments (EDs) with suspected acute coronary syndromes will have mildly abnormal values. However, data regarding rest-stress myocardial perfusion imaging (MPI) in these patients are limited. We hypothesize that stress testing is safe and that the yield for detecting myocardial ischemia is associated with risk stratification by the HEART score.

METHODS AND RESULTS

We conducted a retrospective cohort study of consecutive patients referred for rest-stress MPI with mildly abnormal high-sensitivity troponin T (hs-cTn) values. Outcomes were adverse events related to stress MPI, defined as myocardial infarction or ventricular tachyarrhythmia, and the presence of ischemia, defined as a reversible perfusion defect. Among 213 patients, the median age was 67, most were male (61.5%, n = 131), and prior CAD was common (53.5%, n = 114). Myocardial ischemia was present in 13.6% (n = 29), and there were no adverse events attributable to stress MPI. A higher HEART score was associated with myocardial ischemia (Odds Ratio [OR] 1.50, 95% Confidence Interval [CI] 1.08 to 2.08, P = .002).

CONCLUSION

Rest-stress MPI appears safe in patients with mildly abnormal hs-cTn values, and the yield for detecting ischemia is associated with the HEART score, though further validation studies are needed.

Cardiac troponin and defining myocardial infarction

The 4th Universal Definition of Myocardial Infarction has stimulated considerable debate since its publication in 2018. The intention was to define the types of myocardial injury through the lens of their underpinning pathophysiology. In this review, we discuss how the 4th Universal Definition of Myocardial Infarction defines infarction and injury and the necessary pragmatic adjustments that appear in clinical guidelines to maximize triage of real-world patients.

High-Sensitivity Cardiac Troponin on Presentation to Rule Out Myocardial Infarction: A Stepped-Wedge Cluster Randomized Controlled Trial

BACKGROUND

High-sensitivity cardiac troponin assays enable myocardial infarction to be ruled out earlier, but the safety and efficacy of this approach is uncertain. We investigated whether an early rule-out pathway is safe and effective for patients with suspected acute coronary syndrome.

METHODS

We performed a stepped-wedge cluster randomized controlled trial in the emergency departments of 7 acute care hospitals in Scotland. Consecutive patients presenting with suspected acute coronary syndrome between December 2014 and December 2016 were included. Sites were randomized to implement an early rule-out pathway where myocardial infarction was excluded if high-sensitivity cardiac troponin I concentrations were <5 ng/L at presentation. During a previous validation phase, myocardial infarction was ruled out when troponin concentrations were <99th percentile at 6 to 12 hours after symptom onset. The coprimary outcome was length of stay (efficacy) and myocardial infarction or cardiac death after discharge at 30 days (safety). Patients were followed for 1 year to evaluate safety and other secondary outcomes.

RESULTS

We enrolled 31 492 patients (59±17 years of age [mean±SD]; 45% women) with troponin concentrations <99th percentile at presentation. Length of stay was reduced from 10.1±4.1 to 6.8±3.9 hours (adjusted geometric mean ratio, 0.78 [95% CI, 0.73-0.83]; P<0.001) after implementation and the proportion of patients discharged increased from 50% to 71% (adjusted odds ratio, 1.59 [95% CI, 1.45-1.75]). Noninferiority was not demonstrated for the 30-day safety outcome (upper limit of 1-sided 95% CI for adjusted risk difference, 0.70% [noninferiority margin 0.50%]; P=0.068), but the observed differences favored the early rule-out pathway (0.4% [57/14 700] versus 0.3% [56/16 792]). At 1 year, the safety outcome occurred in 2.7% (396/14 700) and 1.8% (307/16 792) of patients before and after implementation (adjusted odds ratio, 1.02 [95% CI, 0.74-1.40]; P=0.894), and there were no differences in hospital reattendance or all-cause mortality.

CONCLUSIONS

Implementation of an early rule-out pathway for myocardial infarction reduced length of stay and hospital admission. Although noninferiority for the safety outcome was not demonstrated at 30 days, there was no increase in cardiac events at 1 year. Adoption of this pathway would have major benefits for patients and health care providers. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03005158.

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.

High-sensitivity cardiac troponin I: is ethnicity relevant?

AIMS

To evaluate 99th percentile upper reference limits (URLs) and investigate ethnic differences for the Abbott Architect high-sensitivity cardiac troponin I (hs-cTnI) in a middle-aged to elderly cosmopolitan population.

METHODS

In subjects without cardiovascular disease and after outlier exclusion, data on hs-cTnI from 149 white men, 150 white women, 150 South Asian (SA) men and 150 SA women in their sixth, seventh and eight decades were analysed. Each ethnicity-gender-decade subgroup consisted of 50 patients except white men in their sixth decade (n=49).

RESULTS

The overall, women and men hs-cTnI 99th percentile URLs were 22.1, 17.9 and 24.8 ng/L, respectively. Median (IQR) hs-cTnI was higher in men (2.7 (1.8-4.1) ng/L) than in women (1.9 (1.1-3.2) ng/L; p<0.001). White men (3.2 (2.2-4.4) ng/L) had higher hs-cTnI than SA men (2.5 (1.6-3.6) ng/L; p<0.001), white women (2.1 (1.3-3.3) ng/L; p<0.001) and SA women (1.6 (1.0-3.0) ng/L; p<0.001). Hs-cTnI in white women was similar to SA women (p=0.07) and SA men (p=0.07). Patients in the eighth decade had higher hs-cTnI (p<0.05) than those in sixth decade within each ethnicity-gender subgroup. Of significant associations, age had the greatest impact on hs-cTnI followed by gender and then ethnicity.

CONCLUSION

We report white-SA differences in hs-cTnI in men and a similar trend in women. We confirm age and gender differences in hs-cTnI, irrespective of ethnicity. Further studies are required to determine whether ethnicity-specific age and gender 99th percentile URLs improve detection or exclusion of myocardial injury.

Experiences of a One-hour Algorithm in Chest Pain Patients With a Nonelevated Troponin T at Presentation

Supplemental Digital Content is available in the text.

Background:

We aimed to evaluate the use of a 1-hour measurement of high-sensitivity cardiac troponin T (hs-cTnT) in an emergency department (ED) population of chest pain patients with a nonelevated baseline hs-cTnT and to examine the prevalence of early dynamic changes in hs-cTnT and the association with admission rate, diagnosis, and outcome.

Methods:

All patients with a chief complaint of chest pain presenting to the ED of Karolinska University Hospital, Solna, Sweden, from December 2014 to September 2015 who had a baseline hs-cTnT of ≤14 ng/L and a second value obtained within >30 to ≤90 minutes were followed for 30 days regarding admission, readmission, myocardial infarction (MI), and death.

Results:

A total of 1091 patients were included. Dynamic 1-hour changes in hs-cTnT defined as an increase or decrease of ≥3 ng/L occurred in 23 patients (2.1%). Fifteen patients (65.2%) in the dynamic group were admitted, compared with 148 patients (13.9%) in the nondynamic group (P < 0.001). Four of the admitted patients (26.7%) in the dynamic and 1 (0.7%) in the nondynamic group were diagnosed with an MI (P < 0.001). No death or MI occurred within 30 days among those discharged from the ED.

Conclusions:

Dynamic 1-hour changes in hs-cTnT were uncommon but associated with a higher rate of admission and of MI in an unselected population of chest pain patients with a nonelevated hs-cTnT at presentation. Lack of dynamic changes makes MI highly unlikely, and a 1-hour measurement may facilitate an early rule out of MI but should be used together with clinical assessment.

Cardiac Troponin - diagnostic problems and impact on cardiovascular disease

The definition of a high-sensitivity cardiac Troponin (cTn) assay describes the ability to quantify a cardiac biomarker level in at least 50% of healthy individuals. This advance in analytic sensitivity has come with a perceived loss of specificity in the most classic application - chest pain triage and the diagnosis of acute myocardial infarction (AMI). As cardiac Troponin can no longer be used as a dichotomous test, the medical field is increasingly moving towards a more granular interpretation. However, rapid rule-out/rule-in algorithms for AMI still rely on concrete thresholds for efficient triage, irrespective of the patient's comorbidities. Owing to a slightly elevated cTn value, evermore patients appear to fall into an indeterminate risk zone of diagnostic uncertainty. The reasons are manifold, spanning biological variation, analytical issues, increased plasma membrane permeability and the potential cytosolic release of cTn. This review provides a contemporary overview of the literature concerning the use of cardiac Troponin in chronic and acute cardiovascular care. Key messages High-sensitivity cardiac Troponin assays have transformed the assessment of cardiovascular disease. Rapid rule-out algorithms for chest pain triage have become increasingly complicated, but enable safe rule-out. Cardiac Troponin tracks mid- to long-term risk in patients with hyperlipidaemia, heart failure and renal dysfunction.

Collection of human biological samples for research purpose: Key challenges and patients’ perspectives

The development and the access to collections of human biological samples is one of the major challenges for health research. In recent years, biological resource centres (BRCs) have developed in such a way that they provide all activities relating to the handling of samples. In this context, France is undoubtedly a pioneering country, because most of the biological collections available were created on the basis of themed research projects, which involved a particular donor phenotype. The round table was an opportunity to emphasise the persistence of some pitfalls particularly in relation to ensuring the consistency of different regulatory pathways. It also gave the opportunity to question and make recommendations on aspects of governance of biological collections and the BRCs, to state the challenges linked to scientific and economic valorisation and to consider the place of patients and the general public. The development of specific education in public health and research is essential to underline that these initiatives are necessary for developing new diagnostic and therapeutic procedures.

Effect of Definition on Incidence and Prognosis of Type 2 Myocardial Infarction

BACKGROUND

Uncertainties regarding the most appropriate definition and treatment of type 2 myocardial infarction (T2MI) due to supply-demand mismatch have contributed to inconsistent adoption in clinical practice.

OBJECTIVES

This study sought a better understanding of the effect of the definition of T2MI on its incidence, treatment, and event-related mortality, thereby addressing an important unmet clinical need.

METHODS

The final diagnosis was adjudicated in patients presenting with symptoms suggestive of myocardial infarction by 2 independent cardiologists by 2 methods: 1 method required the presence of coronary artery disease, a common interpretation of the 2007 universal definition (T2MI₂₀₀₇); and 1 method did not require coronary artery disease, the 2012 universal definition (T2MI₂₀₁₂).

RESULTS

Overall, 4,015 consecutive patients were adjudicated. The incidence of T2MI based on the T2MI₂₀₀₇ definition was 2.8% (n = 112). The application of the more liberal T2MI₂₀₁₂ definition resulted in an increase of T2MI incidence of 6% (n = 240), a relative increase of 114% (128 reclassified patients, defined as T2MI_{2012reclassified}). Among T2MI₂₀₀₇, 6.3% of patients received coronary revascularization, 22% dual-antiplatelet therapy, and 71% high-dose statin therapy versus 0.8%, 1.6%, and 31% among T2MI_{2012reclassified} patients, respectively (all p < 0.01). Cardiovascular mortality at 90 days was 0% among T2MI_{2012reclassified}, which was similar to patients with noncardiac causes of chest discomfort (0.2%), and lower than T2MI₂₀₀₇ (3.6%) and type 1 myocardial infarction (T1MI) (4.8%) (T2MI_{2012reclassified} vs. T2MI₂₀₀₇ and T1MI: p = 0.03 and 0.01, respectively).

CONCLUSIONS

T2MI_{2012reclassified} has a substantially lower event-related mortality rate compared with T2MI₂₀₀₇ and T1MI. (Advantageous Predictors of Acute Coronary Syndromes Evaluation [APACE] Study; NCT00470587).

Outcomes in Patients With Chest Pain Discharged After Evaluation Using a High-Sensitivity Troponin T Assay

BACKGROUND

Most patients with chest pain are discharged from the emergency department (ED) with the diagnosis "unspecified chest pain." It is unknown if evaluation with a high-sensitivity troponin T (hsTnT) assay affects prognosis in this large population.

OBJECTIVES

The aim was to investigate whether the introduction of an hsTnT assay is associated with reduced incidence of major adverse cardiac events (MACEs) and cardiovascular (CV) risk profile in patients with chest pain discharged from the ED.

METHODS

The study included 65,696 patients with "unspecified chest pain" discharged from 16 Swedish hospital EDs between 2006 and 2013 in which an hsTnT assay was introduced as the clinical routine. Patients evaluated with a conventional and an hsTnT assay were compared regarding the occurrence of 30-day MACE and CV risk profile based on information from national registries. Patients directly discharged and those discharged after an initial admission were analyzed separately.

RESULTS

Fewer directly discharged patients experienced a MACE when evaluated with an hsTnT compared with a conventional assay (0.6% vs. 0.9%; odds ratio [OR]: 0.7; 95% confidence interval [CI]: 0.57 to 0.83). In contrast, more patients discharged after an initial admission experienced a MACE when evaluated with an hsTnT (7.2% vs. 3.4%; OR: 2.18; 95% CI: 1.76 to 2.72). Admitted patients had a higher general CV risk profile when evaluated with hsTnT, whereas directly discharged patients had a lower general CV risk profile with the same test.

CONCLUSIONS

Patients directly discharged from the ED with unspecified chest pain experienced fewer MACEs and had a better risk profile when evaluated with hsTnT. Our findings suggest that more true at-risk patients were identified and admitted. The implementation of hsTnT assays in Swedish hospitals has improved evaluations in the ED.