Acute chest pain in the high-sensitivity cardiac troponin era: A changing role for noninvasive imaging?

Myopericarditis as a Delayed Complication of COVID-19 Infection: A Case Report

Pericarditis is the inflammation of the pericardial layers. Myopericarditis is diagnosed when this inflammation involves the myocardium, which is marked by elevated serum cardiac enzymes. With these two pathologies sharing overlaps in etiology, we present a case of a young patient with a recent history of COVID-19 infection who presented with pleuritic and positional chest pain with troponin I elevation and serial ECG changes attributed to myopericarditis as a post-viral sequela of severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) infection. This case demonstrates the importance of identifying and managing the potential cardiac complications in coronavirus disease 2019 (COVID-19) patients, regardless of age or symptom onset.

Deep Learning Analysis of Chest Radiographs to Triage Patients with Acute Chest Pain Syndrome

Background Patients presenting to the emergency department (ED) with acute chest pain (ACP) syndrome undergo additional testing to exclude acute coronary syndrome (ACS), pulmonary embolism (PE), or aortic dissection (AD), often yielding negative results. Purpose To assess whether deep learning (DL) analysis of the initial chest radiograph may help triage patients with ACP syndrome more efficiently. Materials and Methods This retrospective study used electronic health records of patients with ACP syndrome at presentation who underwent a combination of chest radiography and additional cardiovascular or pulmonary imaging or stress tests at two hospitals (Massachusetts General Hospital [MGH], Brigham and Women's Hospital [BWH]) between January 2005 and December 2015. A DL model was trained on 23 005 patients from MGH to predict a 30-day composite end point of ACS, PE, AD, and all-cause mortality based on chest radiographs. Area under the receiver operating characteristic curve (AUC) was used to compare performance between models (model 1: age + sex; model 2: model 1 + conventional troponin or d-dimer positivity; model 3: model 2 + DL predictions) in internal and external test sets from MGH and BWH, respectively. Results At MGH, 5750 patients (mean age, 59 years ± 17 [SD]; 3329 men, 2421 women) were evaluated. Model 3, which included DL predictions, significantly improved discrimination of those with the composite outcome compared with models 2 and 1 (AUC, 0.85 [95% CI: 0.84, 0.86] vs 0.76 [95% CI: 0.74, 0.77] vs 0.62 [95% CI: 0.60 0.64], respectively; P < .001 for all). When using a sensitivity threshold of 99%, 14% (813 of 5750) of patients could be deferred from cardiovascular or pulmonary testing for differential diagnosis of ACP syndrome using model 3 compared with 2% (98 of 5750) of patients using model 2 (P < .001). Model 3 maintained its diagnostic performance in different age, sex, race, and ethnicity groups. In external validation at BWH (22 764 patients; mean age, 57 years ± 17; 11 470 women), trends were similar and improved after fine tuning. Conclusion Deep learning analysis of chest radiographs may facilitate more efficient triage of patients with acute chest pain syndrome in the emergency department. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Goo in this issue.

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.

Prevalence and Predictors of Obstructive Coronary Artery Disease in Nonlow-risk Acute Chest Pain Patients Who Rule Out for Myocardial Infarction in the High-sensitivity Troponin Era

OBJECTIVES

The best management approach for chest pain patients who rule out for myocardial infarction (MI) in the high-sensitivity troponin (hsTn) era remains elusive. Patients, especially those with nonlow clinical risk scores, are often referred for inpatient ischemic testing to uncover obstructive coronary artery disease (CAD). Whether the prevalence of obstructive CAD in this cohort is high enough to justify routine testing is not known.

METHODS

We conducted a retrospective cohort analysis of 1517 emergency department chest pain patients who ruled out for MI by virtue of a stable high-sensitivity troponin T (hsTnT) levels (defined as <5 ng/L intermeasurements increase) and were admitted for inpatient testing.

RESULTS

Abnormal ischemia evaluation (including 5.9% with evidence of fixed wall motion or perfusion defects) was 11.9%. Of those undergoing invasive angiography (n = 292), significant coronary stenoses (≥70% or unstable lesions) and multivessel CAD occurred in 16.8% and 5.5%, respectively. In a multivariate logistic regression model, known CAD, prior MI, chest pain character, mildly elevated hsTnT, and left ventricular ejection fraction <40% were predictive of an abnormal ischemia evaluation result, whereas electrocardiography findings and the modified History, EKG, Age, Risk factors, and troponin (HEART) score were not. Of note, 30-day adverse cardiac events were strikingly low at 0.4% with no deaths despite an overwhelming majority (>90%) of patients scoring intermediate or high on the modified HEART score.

CONCLUSIONS

A considerable percentage of acute chest pain patients who rule out for MI by hsTn had evidence of obstructive CAD, and the modified HEART score was not predictive of an abnormal ischemia evaluation.

ACR Appropriateness Criteria® Acute Nonspecific Chest Pain-Low Probability of Coronary Artery Disease

Patients with acute nonspecific chest pain and low probability for coronary disease remain an important clinical management dilemma. We focus on evidence for imaging, in an integrated decision-making setting. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Is the true clinical value of high-sensitivity troponins as a biomarker of risk? The concept that detection of high-sensitivity troponin 'never means nothing'

INTRODUCTION

High-sensitivity troponin (hs-cTn) assays are central to the diagnosis of myocardial infarction (MI). Their increased sensitivity has facilitated rapid pathways for the exclusion of MI. However, hs-cTn is now more readily detectable in patients without symptoms typical of MI, in whom a degree of myocardial injury is assumed. Recently, the practice of using the 99^th centile of hs-cTn as a working 'upper reference limit' has been challenged. There is increasing evidence that hs-cTn may provide useful prognostic information, regardless of any suspicion of MI, and as such these assays may have potential as a general biomarker for mortality. This raises the concept that detection of hs-cTn 'never means nothing.'

AREAS COVERED

In this review, we will evaluate the evidence for the use of hs-cTn assays outside their common clinical indication to rule out or diagnose acute MI.

EXPERT OPINION

The data presented suggest that hs-cTn testing may in the future have a generalized role as a biomarker of mortality risk and may be used less as a test for ruling in acute MI, but will remain a frontline test to exclude that diagnosis in ED. Further, the data suggest that the detection of hs-cTn 'never means nothing.'

Pre-hospital delay in patients with acute chest pain

Introduction: Incidence of chest pain and discomfort varies in general population between 2 % and 5 %. Total prehospital delay involves two components: the time it takes for patients to recognise their symptoms as severe and seek medical attention, ie the decision-making time, and the time from seeking help to hospital admission, ie the transport time. Scope of the study was to analyse time loss in patients with chest pain hesitating to contact healthcare services, as well as distribution of acute myocardial infarction (AMI) and angina pectoris (AP) among them. Methods: Retrospective analysis of medical records of physicians working at the emergency medical services (EMS) Department of the City of Belgrade, Serbia, from 20 April 2006 to 22 July 2013 on a total of 5,310 completed field interventions. When placing a call to the EMS, 10.43 % of patients cited chest pain as a major symptom. After deducting all those ones who denied having the symptom on examination thereafter and those for whom there were no data, 349 patients remained, ie 6.57 % of the total number of calls available for analysis. Results: The average time between the onset of chest pain and the decision to call the EMS was 11.97 h, median 2 h and mode 1 h. Patient's minimum prehospital delay was 2 min and the maximum was 20 days. Most patients who experienced chest pain or discomfort waited less than an hour before calling the EMS. Most commonly diagnoses made for a symptom of chest pain were AMI and AP, ie AMI with 12.32 % of the total diagnoses, as well as the elevated arterial pressure. There were more female patients, with no difference found among the age groups. Conclusion: For the majority of patients with chest pain and discomfort presented in this paper the decision-making time was up to one hour, with cardiovascular causes being the at the top of the list.

Multi-Site Coronary Vein Sampling Study on Cardiac Troponin T Degradation in Non-ST-Segment-Elevation Myocardial Infarction: Toward a More Specific Cardiac Troponin T Assay

Background Cardiac troponin T ( cTnT ) is seen in many other conditions besides myocardial infarction, and recent studies demonstrated distinct forms of cTnT . At present, the in vivo formation of these different cTnT forms is incompletely understood. We therefore performed a study on the composition of cTnT during the course of myocardial infarction, including coronary venous system sampling, close to its site of release. Methods and Results Baseline samples were obtained from multiple coronary venous system locations, and a peripheral artery and vein in 71 non- ST -segment-elevation myocardial infarction patients. Additionally, peripheral blood was drawn at 6- and 12-hours postcatheterization. cTnT concentrations were measured using the high-sensitivity- cTnT immunoassay. The cTnT composition was determined via gel filtration chromatography and Western blotting in an early and late presenting patient. High-sensitivity - cTnT concentrations were 28% higher in the coronary venous system than peripherally (n=71, P<0.001). Coronary venous system samples demonstrated cT n T-I-C complex, free intact cTnT , and 29 kD a and 15 to 18 kD a cTnT fragments, all in higher concentrations than in simultaneously obtained peripheral samples. While cT n T-I-C complex proportionally decreased, and disappeared over time, 15 to 18 kD a cTnT fragments increased. Moreover, cT n T-I-C complex was more prominent in the early than in the late presenting patient. Conclusions This explorative study in non- ST -segment-elevation myocardial infarction shows that cTnT is released from cardiomyocytes as a combination of cT n T-I-C complex, free intact cTnT , and multiple cTnT fragments indicating intracellular cTnT degradation. Over time, the cT n T-I-C complex disappeared because of in vivo degradation. These insights might serve as a stepping stone toward a high-sensitivity- cTnT immunoassay more specific for myocardial infarction.

High-sensitive cardiac Troponin T and exercise stress test for evaluation of angiographically significant coronary disease

BACKGROUND

Exercise stress test (EST) has a moderate precision for diagnosis of CAD and could potentially obtain improved accuracy if adding a reliable cardiac biomarker to the test.

OBJECTIVE

We aimed to investigate resting levels and change in hs-cTnT during EST in patients with and without angiographically significant CAD. Moreover, we intended to explore the additive value of hs-cTnT to EST results in diagnosis of stable CAD. We hypothesized that hs-cTnT would be higher in CAD patients and increase diagnostic precision of EST.

METHOD

Patients presenting with symptoms of stable CAD, performed a maximal EST on a bicycle ergometer. Venous blood samples were taken at rest and within 5 min post-exercise. All patients underwent coronary angiography. Significant CAD was defined as having ≥75% stenosis in one or more segments of the coronary arteries.

RESULTS

Out of the 297 participants, significant CAD was found in 111 (37%) patients. Patients with significant CAD compared to without, had higher resting levels of hs-cTnT (median 8.1 vs 5.0 ng/L) and no significant difference in exercise-induced change (median 0.5 vs 0.3 ng/L), p < 0.001 and p = 0.086 respectively. Combined resting hs-cTnT with EST had higher predictive value for significant CAD than EST alone, AUC = 0.751 vs. AUC = 0.637. In an adjusted multivariable regression analysis, resting hs-cTnT >6.0 ng/L was predictive for having significant CAD, OR 2.55 (CI 95% 1.40, 4.65 p = 0.002).

CONCLUSION

In patients with suspected stable CAD, hs-cTnT has a predictive value alone, as well as added to a diagnostic EST for CAD.

Risk stratification for coronary artery disease in multi-ethnic populations: Are there broader considerations for cost efficiency?

Coronary artery disease (CAD) screening and diagnosis are core cardiac specialty services. From symptoms, autopsy correlations supported reductions in coronary blood flow and dynamic epicardial and microcirculatory coronaries artery disease as etiologies. While angina remains a clinical diagnosis, most cases require correlation with a diagnostic modality. At the onset of the evidence building process much research, now factored into guidelines were conducted among population and demographics that were homogenous and often prior to newer technologies being available. Today we see a more diverse multi-ethnic population whose characteristics and risks may not consistently match the populations from which guideline evidence is derived. While it would seem very unlikely that for the majority, scientific arguments against guidelines would differ, however from a translational perspective, there will be populations who differ and importantly there are cost-efficacy questions, e.g., the most suitable first-line tests or what parameters equate to an adequate test. This article reviews non-invasive diagnosis of CAD within the context of multi-ethnic patient populations.

Role of microRNAs in doxorubicin-induced cardiotoxicity: an overview of preclinical models and cancer patients

Cardiotoxicity is a well-known side effect of doxorubicin (DOX), but the mechanisms leading to this phenomenon are still not completely clear. Prediction of drug-induced dysfunction onset is difficult and is still largely based on detection of cardiac troponin (cTn), a circulating marker of heart damage. In the last years, several investigations focused on the possible involvement of microRNAs (miRNAs) in DOX-induced toxicity in vitro, with contrasting results. Recently, several groups employed animal models to mimic patient’s condition, investigate the biological pathways perturbed by DOX, and identify diagnostic markers of cardiotoxicity. We reviewed the results from several studies investigating cardiac miRNAs expression in rodent models of DOX-treatment. We also discussed the data from two publications indicating the possible use of circulating miRNA as biomarkers of DOX-induced cardiotoxicity. Unfortunately, limited information was derived from these studies, as selection methods of candidate-miRNAs and heterogeneity in cardiotoxicity assessment greatly hampered the novelty and robustness of the findings. Nevertheless, at least one circulating miRNA, miR-1, showed a good potential as early biomarker of drug-mediated cardiac dysfunction onset. The use of animal models to investigate DOX-induced cardiotoxicity surely helps narrowing the gap between basic research and clinical practice. Despite this, several issues, including selection of relevant miRNAs and less-than-optimal assessment of cardiotoxicity, greatly limited the results obtained so far. Nonetheless, the association of patients-based studies with the use of preclinical models may be the key to address the many unanswered questions regarding the pathophysiology and early detection of cardiotoxicity.

Identifying Myocardial Ischemia due to Coronary Microvascular Dysfunction in the Emergency Department: Introducing a New Paradigm in Acute Chest Pain Evaluation

Chest pain stands as one of the most frequent patient presentations in the emergency department (ED). Despite established diagnostic algorithms for identifying several important causes of chest pain, such as acute myocardial infarction (AMI), aortic dissection, and pulmonary embolism, guidance on managing patients with recurrent chest pain, one of the top 3 reasons for repeated hospitalization in the United States, is less defined. The assessment of symptoms, serial ECG, and necrosis biomarkers plays a major role in patient management. Notably, the recently introduced high-sensitivity troponin T (hs-TnT) assay is helping to identify ischemia in patients previously undiagnosed by conventional testing. In Europe, with the use of this assay for over a decade, the identification of patients with AMI has substantially increased, particularly of patients with type 2 AMI, which is seen in the absence of atherosclerotic obstruction of the epicardial coronaries on angiography. Use of hs-TnT is in particular relevant in women, in whom the use of a sex-specific threshold for elevated hs-TnT has almost doubled the diagnosis of AMI. With the advent of the hs-TnT assay in the United States in 2017, a similar phenomenon is expected. Thus, it is important to learn from the European experience and to develop sex-specific nuanced algorithms for the evaluation of additional causes of myocardial ischemia/necrosis, such as coronary artery vasomotor disorders and coronary microvascular dysfunction. The latter has a high prevalence among symptomatic women presenting to the ED, a group in whom recurrent chest pain is common. This commentary describes the tools available for diagnosing epicardial- and non-epicardial-related myocardial ischemia in patients with recurrent chest pain in the ED setting. A sex-specific, nuanced approach applied to select groups of patients being observed in the ED has the potential to reduce admissions and to allow for the initiation of timely, appropriate medical treatment and outpatient follow-up in an at-risk population. The costs and availability of advanced diagnostics may pose some limitation to the widespread adoption of such protocols.

Risk stratification and role for additional diagnostic testing in patients with acute chest pain and normal high-sensitivity cardiac troponin levels

Background

Normal high sensitivity cardiac troponin (hs-cTn) assays rule out acute myocardial infarction (AMI) with great accuracy, but additional non-invasive testing is frequently ordered. This observational study evaluates whether clinical characteristics can contribute to risk stratification and could guide referral for additional testing.

Methods

918 serial patients with acute chest pain and normal hs-cTnT levels were prospectively included. Major adverse cardiac events (MACE) and non-invasive test results were assessed during one-year follow-up. Patients were classified as low and high risk based on clinical characteristics.

Results

MACE occurred in 6.1% of patients and mainly comprised revascularizations (86%). A recent abnormal stress test, suspicious history, a positive family history and higher baseline hs-cTnT levels were independent predictors of MACE with odds ratios of 16.00 (95%CI:6.25–40.96), 16.43 (6.36–42.45), 2.33 (1.22–4.42) and 1.10 (1.01–1.21), respectively. Absence of both recent abnormal stress test and suspicious history identified 86% of patients. These patients were at very low risk for MACE (0.4% in 30-days and 2.3% in one-year). Despite this, the majority (287/345 = 83%) of additional tests were performed in low risk patients, with <10% abnormal test findings. The diagnostic yield was significantly higher in the remaining higher risk patients, 40% abnormal test findings and a positive predictive value of 70% for MACE. Similar results were observed in patients without known coronary artery disease.

Conclusions

Clinical characteristics can be used to identify low risk patients with acute chest pain and normal hs-cTnT levels. Current strategies in the emergency department result in numerous additional tests, which are mostly ordered in patients at very low risk and have a low diagnostic yield.

Predictive significance of detectable cardiac troponin I measured with a contemporary-sensitive assay in a real life experience

BACKGROUND

Cardiac troponin (cTn) testing has reduced the likelihood of erroneous discharge of patients with acute coronary syndrome (ACS) from the emergency department (ED), but doubts remain about optimal clinical use. This study was planned for evaluating the predictive significance of cTn values between the limit of detection of the method and the 99th percentile in ED patients evaluated for suspected ACS.

METHODS

In this retrospective study all hospital records of patients admitted over a 6-month period to the ED and with at least one cTnI value comprised between the limit of detection (0.01 ng/mL) and the 99th percentile of the assay (0.05 ng/mL) were analyzed.

RESULTS

A total of 4,749 patients with cTnI value between 0.01-0.05 ng/mL were identified among 57,879 ED visits throughout the study period. Overall, 2,189 patients (46.1%) were discharged from the ED, 2,529 (53.25%) were admitted to the hospital and 31 (0.65%) died during ED stay. A total number of 289 patients out of 2,189 who were discharged (i.e., 13.2%) had additional ED visits within 30 days. Among these, 6 were diagnosed with ACS, representing 0.27% of patients discharged [negative predictive value (NPV) 0.997; 95% CI, 0.994-0.999] and 2.1% of those with second admission (NPV 0.979; 95% CI, 0.955-0.992). Only one of the 2,529 patients admitted to the hospital (i.e., 0.04%) developed an ACS during hospital stay.

CONCLUSIONS

The results of our retrospective study suggest that the suitability of using a contemporary-sensitive cTnI immunoassay assay in the context of an appropriate protocol represents a safe and effective strategy for ruling in and ruling out ACS in patients presenting to the ED.