MIC-1, a novel macrophage inhibitory cytokine, is a divergent member of the TGF-beta superfamily

Macrophages play a key role in both normal and pathological processes involving immune and inflammatory responses, to a large extent through their capacity to secrete a wide range of biologically active molecules. To identify some of these as yet not characterized molecules, we have used a subtraction cloning approach designed to identify genes expressed in association with macrophage activation. One of these genes, designated macrophage inhibitory cytokine 1 (MIC-1), encodes a protein that bears the structural characteristics of a transforming growth factor beta (TGF-beta) superfamily cytokine. Although it belongs to this superfamily, it has no strong homology to existing families, indicating that it is a divergent member that may represent the first of a new family within this grouping. Expression of MIC-1 mRNA in monocytoid cells is up-regulated by a variety of stimuli associated with activation, including interleukin 1beta, tumor necrosis factor alpha (TNF-alpha), interleukin 2, and macrophage colony-stimulating factor but not interferon gamma, or lipopolysaccharide (LPS). Its expression is also increased by TGF-beta. Expression of MIC-1 in CHO cells results in the proteolytic cleavage of the propeptide and secretion of a cysteine-rich dimeric protein of Mr 25 kDa. Purified recombinant MIC-1 is able to inhibit lipopolysaccharide -induced macrophage TNF-alpha production, suggesting that MIC-1 acts in macrophages as an autocrine regulatory molecule. Its production in response to secreted proinflammatory cytokines and TGF-beta may serve to limit the later phases of macrophage activation.

The HEART Pathway randomized trial: identifying emergency department patients with acute chest pain for early discharge

BACKGROUND

The HEART Pathway is a decision aid designed to identify emergency department patients with acute chest pain for early discharge. No randomized trials have compared the HEART Pathway with usual care.

METHODS AND RESULTS

Adult emergency department patients with symptoms related to acute coronary syndrome without ST-elevation on ECG (n=282) were randomized to the HEART Pathway or usual care. In the HEART Pathway arm, emergency department providers used the HEART score, a validated decision aid, and troponin measures at 0 and 3 hours to identify patients for early discharge. Usual care was based on American College of Cardiology/American Heart Association guidelines. The primary outcome, objective cardiac testing (stress testing or angiography), and secondary outcomes, index length of stay, early discharge, and major adverse cardiac events (death, myocardial infarction, or coronary revascularization), were assessed at 30 days by phone interview and record review. Participants had a mean age of 53 years, 16% had previous myocardial infarction, and 6% (95% confidence interval, 3.6%-9.5%) had major adverse cardiac events within 30 days of randomization. Compared with usual care, use of the HEART Pathway decreased objective cardiac testing at 30 days by 12.1% (68.8% versus 56.7%; P=0.048) and length of stay by 12 hours (9.9 versus 21.9 hours; P=0.013) and increased early discharges by 21.3% (39.7% versus 18.4%; P<0.001). No patients identified for early discharge had major adverse cardiac events within 30 days.

CONCLUSIONS

The HEART Pathway reduces objective cardiac testing during 30 days, shortens length of stay, and increases early discharges. These important efficiency gains occurred without any patients identified for early discharge suffering MACE at 30 days.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique Identifier: NCT01665521.

Safely Identifying Emergency Department Patients With Acute Chest Pain for Early Discharge

BACKGROUND

The HEART Pathway (history, ECG, age, risk factors, and initial troponin) is an accelerated diagnostic protocol designed to identify low-risk emergency department patients with chest pain for early discharge without stress testing or angiography. The objective of this study was to determine whether implementation of the HEART Pathway is safe (30-day death and myocardial infarction rate <1% in low-risk patients) and effective (reduces 30-day hospitalizations) in emergency department patients with possible acute coronary syndrome.

METHODS

A prospective pre-post study was conducted at 3 US sites among 8474 adult emergency department patients with possible acute coronary syndrome. Patients included were ≥21 years old, investigated for possible acute coronary syndrome, and had no evidence of ST-segment-elevation myocardial infarction on ECG. Accrual occurred for 12 months before and after HEART Pathway implementation from November 2013 to January 2016. The HEART Pathway accelerated diagnostic protocol was integrated into the electronic health record at each site as an interactive clinical decision support tool. After accelerated diagnostic protocol integration, ED providers prospectively used the HEART Pathway to identify patients with possible acute coronary syndrome as low risk (appropriate for early discharge without stress testing or angiography) or non-low risk (appropriate for further in-hospital evaluation). The primary safety and effectiveness outcomes, death, and myocardial infarction (MI) and hospitalization rates at 30 days were determined from health records, insurance claims, and death index data.

RESULTS

Preimplementation and postimplementation cohorts included 3713 and 4761 patients, respectively. The HEART Pathway identified 30.7% as low risk; 0.4% of these patients experienced death or MI within 30 days. Hospitalization at 30 days was reduced by 6% in the postimplementation versus preimplementation cohort (55.6% versus 61.6%; adjusted odds ratio, 0.79; 95% CI, 0.71-0.87). During the index visit, more MIs were detected in the postimplementation cohort (6.6% versus 5.7%; adjusted odds ratio, 1.36; 95% CI, 1.12-1.65). Rates of death or MI during follow-up were similar (1.1% versus 1.3%; adjusted odds ratio, 0.88; 95% CI, 0.58-1.33).

CONCLUSIONS

HEART Pathway implementation was associated with decreased hospitalizations, increased identification of index visit MIs, and a very low death and MI rate among low-risk patients. These findings support use of the HEART Pathway to identify low-risk patients who can be safely discharged without stress testing or angiography.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov . Unique identifier: NCT02056964.

Identifying patients for early discharge: performance of decision rules among patients with acute chest pain

BACKGROUND

The HEART score and North American Chest Pain Rule (NACPR) are decision rules designed to identify acute chest pain patients for early discharge without stress testing or cardiac imaging. This study compares the clinical utility of these decision rules combined with serial troponin determinations.

METHODS AND RESULTS

A secondary analysis was conducted of 1005 participants in the Myeloperoxidase In the Diagnosis of Acute coronary syndromes Study (MIDAS). MIDAS is a prospective observational cohort of Emergency Department (ED) patients enrolled from 18 US sites with symptoms suggestive of acute coronary syndrome (ACS). The ability to identify participants for early discharge and the sensitivity for ACS at 30 days were compared among an unstructured assessment, NACPR, and HEART score, each combined with troponin measures at 0 and 3h. ACS, defined as cardiac death, acute myocardial infarction, or unstable angina, occurred in 22% of the cohort. The unstructured assessment identified 13.5% (95% CI 11.5-16%) of participants for early discharge with 98% (95% CI 95-99%) sensitivity for ACS. The NACPR identified 4.4% (95% CI 3-6%) for early discharge with 100% (95% CI 98-100%) sensitivity for ACS. The HEART score identified 20% (95% CI 18-23%) for early discharge with 99% (95% CI 97-100%) sensitivity for ACS. The HEART score had a net reclassification improvement of 10% (95% CI 8-12%) versus unstructured assessment and 19% (95% CI 17-21%) versus NACPR.

CONCLUSIONS

The HEART score with 0 and 3 hour serial troponin measures identifies a substantial number of patients for early discharge while maintaining high sensitivity for ACS.

Recommendations for Institutions Transitioning to High-Sensitivity Troponin Testing: JACC Scientific Expert Panel

High-sensitivity cardiac troponin (hs-cTn) I or T methods have been in use in certain regions for years but are now increasingly globally adopted, including in the United States. Accordingly, inevitable challenges are created for institutions transitioning from conventional cardiac troponin (cTn) assays. hs-cTn assays have higher analytic precision at lower concentrations, yielding greater clinical sensitivity for myocardial injury and allowing accurate recognition of small changes in troponin concentration (rise or fall) within a short time frame. Although much of the knowledge regarding troponin biology that was applicable with older troponin assays still holds true, considerable education regarding the differences between conventional cTn and hs-cTn is needed before medical systems convert to the newer methods. This includes a basic understanding of how hs-cTn testing differs from conventional cTn testing and how it is best deployed in different settings, such as the emergency department and inpatient services. This Expert Panel will review important concepts for institutional transition to hs-cTn methodology, providing recommendations useful for education before implementation.

Resuscitation with balanced electrolyte solution prevents hyperchloremic metabolic acidosis in patients with diabetic ketoacidosis

OBJECTIVE

The objective of the study was to determine if balanced electrolyte solution (BES) prevents hyperchloremic metabolic acidosis in patients with diabetic ketoacidosis (DKA).

METHODS

This is a prospective, randomized, double-blind study. A convenience sample of DKA patients aged 18 to 65 years with serum bicarbonate less than or equal to 15 and anion gap greater than or equal to 16 was enrolled at "Louisiana State University Health Sciences Center-Shreveport" an capitalize Emergency Department over a 24-month period (2006-2008). Patients were randomized to standardized resuscitation with normal saline (NS) or BES (Plasma-Lyte A pH 7.4; Baxter International, Deerfield, IL). Every 2 hours, serum chloride and bicarbonate were measured until the patient's anion gap decreased to 12. An intention-to-treat analysis was performed on patients who met inclusion criteria and received at least 4 hours of study fluid. Chloride and bicarbonate measurements from the BES and NS groups were compared using unpaired and paired Student t tests.

RESULTS

Of 52 patients enrolled, 45 (22 in BES group and 23 in NS group) met inclusion criteria and received 4 hours of fluid. The mean postresuscitation chloride was 111 mmol/L (95% confidence interval [CI] = 110-112) in the NS group and 105 mmol/L (95% CI = 103-108) in the BES group (P ≤ .001). The mean postresuscitation bicarbonate was 17 mmol/L (95% CI = 15-18) in the NS group and 20 mmol/L (95% CI = 18-21) in the BES group (P = .020).

CONCLUSIONS

Resuscitation of DKA patients with BES results in lower serum chloride and higher bicarbonate levels than patients receiving NS, consistent with prevention of hyperchloremic metabolic acidosis.

High-Sensitivity Cardiac Troponin and the 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guidelines for the Evaluation and Diagnosis of Acute Chest Pain

The 2021 American Heart Association/American College of Cardiology/American Society of Echocardiography/American College of Chest Physicians/Society for Academic Emergency Medicine/Society of Cardiovascular Computed Tomography/Society for Cardiovascular Magnetic Resonance guidelines for the evaluation and diagnosis of acute chest pain make important recommendations that include the recognition of high-sensitivity cardiac troponin (hs-cTn) as the preferred biomarker, endorsement of 99th percentile upper reference limits to define myocardial injury, and the use of clinical decision pathways, as well as acknowledgment of the uniqueness of women and other patient subsets. Details on how to integrate hs-cTn into clinical practice are less extensively addressed. Clinicians should be aware of some of the analytical aspects related to hs-cTn assays regarding the limit of detection and the limit of quantitation and how they are used clinically, especially for the single sample strategy to rule out acute myocardial infarction. Likewise, it is important for clinicians to understand issues related to the derivation of the 99th percentile upper reference limit; the value of sex-specific 99th percentile upper reference limits; how to use changing concentrations (deltas) to facilitate diagnosis and risk stratification of patients with suspected acute coronary syndrome, including the differentiation of acute from chronic myocardial injury; and how to best integrate the use of hs-cTn with clinical decision pathways. With the use of hs-cTn, conditions such as type 2 myocardial infarction become more common, whereas others such as unstable angina become less frequent but still occur. Sections relating to these issues are included.

Role of environmental conditions on the expression levels, glycoform pattern and levels of sialyltransferase for hFSH produced by recombinant CHO cells

A recombinant CHO cell line in which the expression of human follicle stimulating hormone (hFSH) was under the control of the beta actin promoter was maintained in steady state perfusion cultures on a protein free medium. The level of expression of the hFSH was controlled by varying the steady state level of dissolved oxygen (10-90% of air saturation) and of sodium butyrate (0-1.5mM). Under these conditions, the specific productivity of hFSH (qFSH) varied from 0.7 to 4.8 ng hFSH/10(6) cells/h. As the specific productivity of hFSH increased, there was a shift in the FSH isoforms to the lower pI fractions, corresponding to increased sialic acid content. As the specific productivity of hFSH increased, shifting the isoform distribution towards the lower pI isoforms, that the sialyltransferase enzymic activity also increased.

The changing base line of complex ventricular arrhythmias. A new consideration in assessing long-term antiarrhythmic drug therapy

Initial base-line electrocardiograms are used to assess the efficacy of treatment for ventricular arrhythmias. This approach assumes that in the absence of treatment the frequency of arrhythmia would remain constant. To test the validity of this assumption, we studied 26 clinically stable patients with symptomatic but not life-threatening ventricular arrhythmias, during two periods of placebo treatment separated by a mean of 17 months. As compared with the initial placebo period, there were significant reductions in ventricular premature depolarizations (50 per cent), pairs (65 per cent), and ventricular tachycardia (83 per cent) during the second period of placebo administration (P less than or equal to 0.05 for all comparisons). Over one third of the patients gave the appearance of receiving successful therapy during the second placebo period, even when the reported spontaneous variability of ventricular arrhythmia was taken into consideration. If unrecognized, these long-term spontaneous changes in the frequency of arrhythmia could result in continuation of unnecessary and potentially toxic therapy and lead to incorrect conclusions regarding the efficacy of antiarrhythmic drugs in clinical trials. We therefore recommend that the frequency of arrhythmia be reassessed annually in the absence of treatment in patients similar to those in our study. These recommendations should not be applied to patients with life-threatening ventricular arrhythmias.

Adenosine triphosphate is released during injurious mechanical ventilation and contributes to lung edema

BACKGROUND

Extracellular nucleotides mediate many cellular functions and are released in response to mechanical stress in vitro. It is unknown whether adenosine triphosphate (ATP) is released in vivo during mechanical ventilation (MV). We hypothesized that stress from high-pressure MV would increase airway ATP, contributing to MV-associated lung edema.

METHODS

Rats were randomized to nonventilated control (n = 6) or 30 minutes of MV with low (15 cm H(2)0, n = 7) or high (40 cm H(2)0, n = 6) pressure. Additional groups received intratracheal ATP (n = 7) or saline (n = 7) before low-pressure MV.

RESULTS

Low-pressure MV did not affect lung edema or bronchoalveolar lavage (BAL) ATP levels. In contrast, high-pressure MV significantly increased BAL ATP and produced alveolar edema; lactate dehydrogenase was unchanged. Intratracheal ATP administration significantly increased lung water during low-pressure MV.

CONCLUSION

High-pressure MV increases BAL ATP concentration without altering lactate dehydrogenase, suggesting that release is not from cell lysis. Intratracheal ATP increases lung water, implicating nucleotides in MV-associated lung edema.

Techniques for teaching electrocardiogram interpretation: self-directed learning is less effective than a workshop or lecture

CONTEXT

Teaching 12-lead electrocardiogram (ECG) interpretation to students and residents is a challenge for medical educators. To date, few studies have compared the effectiveness of different techniques used for ECG teaching.

OBJECTIVES

This study aimed to determine if common teaching techniques, such as those involving workshops, lectures and self-directed learning (SDL), increase medical students' ability to correctly interpret ECGs. It also aimed to compare the effectiveness of these formats.

METHODS

  This was a prospective randomised study conducted over a 28-month period. Year 4 medical students were randomised to receive teaching in ECG interpretation using one of three teaching formats: workshop, lecture or SDL. All three formats covered the same content. Students were administered three tests: a pre-test (before teaching); a post-test (immediately after teaching), and a retention test (1 week after teaching). Each tested the same content using 25 questions worth 1 point each. A mixed-model repeated-measures analysis of variance (anova) with least squares post hoc analysis was conducted to determine if differences in test scores between the formats were statistically significant.

RESULTS

Of the 223 students for whom data were analysed, 79 were randomised to a workshop, 82 to a lecture-based format and 62 to SDL. All three teaching formats resulted in a statistically significant improvement in individual test scores (p < 0.001). Comparison of the lecture- and workshop-based formats demonstrated no difference in test scores (marginal mean [MM] for both formats = 12.4, 95% confidence interval [95% CI] 11.7-13.2]; p = 0.99). Test scores of students using SDL (MM = 10.7, 95% CI 9.8-11.5) were lower than those of students in the workshop (p = 0.003) and lecture (p = 0.002) groups.

CONCLUSIONS

Compared with those taught using workshop- and lecture-based formats, medical students learning ECG interpretation by SDL had lower test scores.

Diagnostic Performance of High-Sensitivity Cardiac Troponin T Strategies and Clinical Variables in a Multisite US Cohort

BACKGROUND

European data support the use of low high-sensitivity troponin (hs-cTn) measurements or a 0/1-hour (0/1-h) algorithm for myocardial infarction to exclude major adverse cardiac events (MACEs) among patients in the emergency department with possible acute coronary syndrome. However, modest US data exist to validate these strategies. This study evaluated the diagnostic performance of an initial hs-cTnT measure below the limit of quantification (LOQ: 6 ng/L), a 0/1-h algorithm, and their combination with history, ECG, age, risk factors, and initial troponin (HEART) scores for excluding MACE in a multisite US cohort.

METHODS

A prospective cohort study was conducted at 8 US sites, enrolling adult patients in the emergency department with symptoms suggestive of acute coronary syndrome and without ST-elevation on ECG. Baseline and 1-hour blood samples were collected, and hs-cTnT (Roche; Basel, Switzerland) was measured. Treating providers blinded to hs-cTnT results prospectively calculated HEART scores. MACE (cardiac death, myocardial infarction, and coronary revascularization) at 30 days was adjudicated. The proportion of patients with initial hs-cTnT measures below the LOQ and risk according to a 0/1-h algorithm was determined. The negative predictive value (NPV) was calculated for both strategies when used alone or with a HEART score.

RESULTS

Among 1462 participants with initial hs-cTnT measures, 46.4% (678 of 1462) were women and 37.1% (542 of 1462) were Black with an age of 57.6±12.9 (mean±SD) years. MACEs at 30 days occurred in 14.4% (210 of 1462) of participants. Initial hs-cTnT measures below the LOQ occurred in 32.8% (479 of 1462), yielding an NPV of 98.3% (95% CI, 96.7-99.3) for 30-day MACEs. A low-risk HEART score with an initial hs-cTnT below the LOQ occurred in 20.1% (294 of 1462), yielding an NPV of 99.0% (95% CI, 97.0-99.8) for 30-day MACEs. A 0/1-h algorithm was complete in 1430 patients, ruling out 57.8% (826 of 1430) with an NPV of 97.2% (95% CI, 95.9-98.2) for 30-day MACEs. Adding a low HEART score to the 0/1-h algorithm ruled out 30.8% (441 of 1430) with an NPV of 98.4% (95% CI, 96.8-99.4) for 30-day MACEs.

CONCLUSIONS

In a prospective multisite US cohort, an initial hs-cTnT below the LOQ combined with a low-risk HEART score has a 99% NPV for 30-day MACEs. The 0/1-h hs-cTnT algorithm did not achieve an NPV >99% for 30-day MACEs when used alone or with a HEART score. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02984436.

Leukocyte emigration and migration in the vagina following mating in the rabbit

Within 45 minutes after mating in the rabbit, numerous heterophil leukocytes adhere to the endothelium of venules in the vagina. Initial association appears to occur via small protuberances from the leukocyte which fit into small indentions in the endothelial cell. Following adherence, leukocytes flatten and pass between endothelial cells. A regular intercellular space separates the leukocyte from the endothelial cells. Leukocytes subsequently migrate through the connective tissue to the epithelium. By three hours postcoitus, the region beneath the basement lamina of the vaginal epithelium is crowded with numerous juxtaposed leukocytes. Leukocytes subsequently migrate between epithelial cells into the vaginal lumen where they actively engulf spermatozoa. Spermatozoa appear to be ingested head first. Numerous small filaments are observed in the leukocyte cytoplasm in the region adjacent to the sperm head. Degranulation of azurophyl granules follows sperm uptake. The leukocyte response can be elicited either by spermatozoa (from the epididymis) or by semen (from vasectomized bucks), but is not elicited by ovulation (with human chorionic gonadotropin). It is suggested that the response may be initiated because the vagina does not distinguish between semen, spermatozoa and bacterial infection.

Cost analysis of the History, ECG, Age, Risk factors, and initial Troponin (HEART) Pathway randomized control trial

INTRODUCTION

The HEART Pathway is a diagnostic protocol designed to identify low-risk patients presenting to the emergency department with chest pain that are safe for early discharge. This protocol has been shown to significantly decrease health care resource utilization compared with usual care. However, the impact of the HEART Pathway on the cost of care has yet to be reported.

METHODS AND RESULTS

We performed a cost analysis of patients enrolled in the HEART Pathway trial, which randomized participants to either usual care or the HEART Pathway protocol. For low-risk patients, the HEART Pathway recommended early discharge from the emergency department without further testing. We compared index visit cost, cost at 30 days, and cardiac-related health care cost at 30 days between the 2 treatment arms. Costs for each patient included facility and professional costs. Cost at 30 days included total inpatient and outpatient costs, including the index encounter, regardless of etiology. Cardiac-related health care cost at 30 days included the index encounter and costs adjudicated to be cardiac-related within that period. Two hundred seventy of the 282 patients enrolled in the trial had cost data available for analysis. There was a significant reduction in cost for the HEART Pathway group at 30 days (median cost savings of $216 per individual), which was most evident in low-risk (Thrombolysis In Myocardial Infarction score of 0-1) patients (median savings of $253 per patient) and driven primarily by lower cardiac diagnostic costs in the HEART Pathway group.

CONCLUSIONS

Using the HEART Pathway as a decision aid for patients with undifferentiated chest pain resulted in significant cost savings.

Early Rule-Out and Rule-In Strategies for Myocardial Infarction

BACKGROUND

Patients with chest pain comprise a large proportion of emergency presentations and place a major burden on healthcare resources. Therefore, efforts to safely and rapidly identify those with and without acute myocardial infarction (AMI) are needed. The challenge for clinicians is to accurately identify patients with acute coronary syndromes, while balancing the need to safely and rapidly reassure and discharge those without serious conditions.

CONTENT

This review summarizes the evidence to date on optimum accelerated strategies for the rule-in and rule-out of AMI, using strategies focused on optimum use of troponin results. Evidence based on both sensitive and highly sensitive troponin assay results is presented. The use of novel biomarkers is also addressed and the combination of biomarkers with other clinical information in accelerated diagnostic strategies is discussed.

SUMMARY

The majority of patients, who are not at risk of myocardial infarction or other serious harm, may be suitable for discharge directly from the emergency setting using approaches focused on troponin algorithms and accelerated diagnostic protocols. Evidence about the clinical and health economic impact of use of such strategies is needed, as they may have major benefits for both patients and healthcare providers.

Provider-directed imaging stress testing reduces health care expenditures in lower-risk chest pain patients presenting to the emergency department

BACKGROUND

Among intermediate- to high-risk patients with chest pain, we have shown that a cardiac magnetic resonance (CMR) stress test strategy implemented in an observation unit (OU) reduces 1-year health care costs compared with inpatient care. In this study, we compare 2 OU strategies to determine among lower-risk patients if a mandatory CMR stress test strategy was more effective than a physicians' ability to select a stress test modality.

METHODS AND RESULTS

On emergency department arrival and referral to the OU for management of low- to intermediate-risk chest pain, 120 individuals were randomly assigned to receive (1) a CMR stress imaging test (n=60) or (2) a provider-selected stress test (n=60: stress echo [62%], CMR [32%], cardiac catheterization [3%], nuclear [2%], and coronary CT [2%]). No differences were detected in length of stay (median CMR=24.2 hours versus 23.8 hours, P=0.75), catheterization without revascularization (CMR=0% versus 3%), appropriateness of admission decisions (CMR 87% versus 93%, P=0.36), or 30-day acute coronary syndrome (both 3%). Median cost was higher among those randomly assigned to the CMR-mandated group ($2005 versus $1686, P<0.001).

CONCLUSIONS

In patients with lower-risk chest pain receiving emergency department-directed OU care, the ability of a physician to select a cardiac stress imaging modality (including echocardiography, CMR, or radionuclide testing) was more cost-effective than a pathway that mandates a CMR stress test. Contrary to prior observations in individuals with intermediate- to high-risk chest pain, in those with lower-risk chest pain, these results highlight the importance of physician-related choices during acute coronary syndrome diagnostic protocols.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00869245.

Adherence to an Accelerated Diagnostic Protocol for Chest Pain: Secondary Analysis of the HEART Pathway Randomized Trial

OBJECTIVES

Accelerated diagnostic protocols (ADPs), such as the HEART Pathway, are gaining popularity in emergency departments (EDs) as tools used to risk stratify patients with acute chest pain. However, provider nonadherence may threaten the safety and effectiveness of ADPs. The objective of this study was to determine the frequency and impact of ADP nonadherence.

METHODS

A secondary analysis of participants enrolled in the HEART Pathway RCT was conducted. This trial enrolled 282 adult ED patients with symptoms concerning for acute coronary syndrome without ST-elevation on electrocardiogram. Patients randomized to the HEART Pathway (N = 141) were included in this analysis. Outcomes included index visit disposition, nonadherence, and major adverse cardiac events (MACEs) at 30 days. MACE was defined as death, myocardial infarction, or revascularization. Nonadherence was defined as: 1) undertesting-discharging a high-risk patient from the ED without objective testing (stress testing or coronary angiography) or 2) overtesting-admitting or obtaining objective testing on a low-risk patient.

RESULTS

Nonadherence to the HEART Pathway occurred in 28 of 141 patients (20%, 95% confidence interval [CI] = 14% to 27%). Overtesting occurred in 19 of 141 patients (13.5%, 95% CI = 8% to 19%) and undertesting in nine of 141 patients (6%, 95% CI = 3% to 12%). None of these 28 patients suffered MACE. The net effect of nonadherence was 10 additional admissions among patients identified as low-risk and appropriate for early discharge (absolute decrease in discharge rate of 7%, 95% CI = 3% to 13%).

CONCLUSIONS

Real-time use of the HEART Pathway resulted in a nonadherence rate of 20%, mostly due to overtesting. None of these patients had MACE within 30 days. Nonadherence decreased the discharge rate, attenuating the HEART Pathway's impact on health care use.

HEART Pathway Accelerated Diagnostic Protocol Implementation: Prospective Pre-Post Interrupted Time Series Design and Methods

Background

Most patients presenting to US Emergency Departments (ED) with chest pain are hospitalized for comprehensive testing. These evaluations cost the US health system >$10 billion annually, but have a diagnostic yield for acute coronary syndrome (ACS) of <10%. The history/ECG/age/risk factors/troponin (HEART) Pathway is an accelerated diagnostic protocol (ADP), designed to improve care for patients with acute chest pain by identifying patients for early ED discharge. Prior efficacy studies demonstrate that the HEART Pathway safely reduces cardiac testing, while maintaining an acceptably low adverse event rate.

Objective

The purpose of this study is to determine the effectiveness of HEART Pathway ADP implementation within a health system.

Methods

This controlled before-after study will accrue adult patients with acute chest pain, but without ST-segment elevation myocardial infarction on electrocardiogram for two years and is expected to include approximately 10,000 patients. Outcomes measures include hospitalization rate, objective cardiac testing rates (stress testing and angiography), length of stay, and rates of recurrent cardiac care for participants.

Results

In pilot data, the HEART Pathway decreased hospitalizations by 21%, decreased hospital length (median of 12 hour reduction), without increasing adverse events or recurrent care. At the writing of this paper, data has been collected on >5000 patient encounters. The HEART Pathway has been fully integrated into health system electronic medical records, providing real-time decision support to our providers.

Conclusions

We hypothesize that the HEART Pathway will safely reduce healthcare utilization. This study could provide a model for delivering high-value care to the 8-10 million US ED patients with acute chest pain each year.

ClinicalTrial

Clinicaltrials.gov NCT02056964; https://clinicaltrials.gov/ct2/show/NCT02056964 (Archived by WebCite at http://www.webcitation.org/6ccajsgyu)

Performance of the European Society of Cardiology 0/1-Hour Algorithm With High-Sensitivity Cardiac Troponin T Among Patients With Known Coronary Artery Disease

Importance

The European Society of Cardiology (ESC) 0/1-hour algorithm is a validated high-sensitivity cardiac troponin (hs-cTn) protocol for emergency department patients with possible acute coronary syndrome. However, limited data exist regarding its performance in patients with known coronary artery disease (CAD; prior myocardial infarction [MI], coronary revascularization, or ≥70% coronary stenosis).

Objective

To evaluate and compare the diagnostic performance of the ESC 0/1-hour algorithm for 30-day cardiac death or MI among patients with and without known CAD and determine if the algorithm could achieve the negative predictive value rule-out threshold of 99% or higher.

Design, Setting, and Participants

This was a preplanned subgroup analysis of the STOP-CP prospective multisite cohort study, which was conducted from January 25, 2017, through September 6, 2018, at 8 emergency departments in the US. Patients 21 years or older with symptoms suggestive of acute coronary syndrome without ST-segment elevation on initial electrocardiogram were included. Analysis took place between February and December 2022.

Interventions/Exposures

Participants with 0- and 1-hour high-sensitivity cardiac troponin T (hs-cTnT) measures were stratified into rule-out, observation, and rule-in zones using the ESC 0/1-hour hs-cTnT algorithm.

Main Outcomes and Measures

Cardiac death or MI at 30 days determined by expert adjudicators.

Results

During the study period, 1430 patients were accrued. In the cohort, 775 individuals (54.2%) were male, 826 (57.8%) were White, and the mean (SD) age was 57.6 (12.8) years. At 30 days, cardiac death or MI occurred in 183 participants (12.8%). Known CAD was present in 449 (31.4%). Among patients with known CAD, the ESC 0/1-hour algorithm classified 178 of 449 (39.6%) into the rule-out zone compared with 648 of 981 (66.1%) without CAD (P < .001). Among rule-out zone patients, 30-day cardiac death or MI occurred in 6 of 178 patients (3.4%) with known CAD and 7 of 648 (1.1%) without CAD (P < .001). The negative predictive value for 30-day cardiac death or MI was 96.6% (95% CI, 92.8-98.8) among patients with known CAD and 98.9% (95% CI, 97.8-99.6) in patients without known CAD (P = .04).

Conclusions and Relevance

Among patients with known CAD, the ESC 0/1-hour hs-cTnT algorithm was unable to safely exclude 30-day cardiac death or MI. This suggests that clinicians should be cautious if using the algorithm in patients with known CAD. The negative predictive value was significantly higher in patients without a history of CAD but remained less than 99%.

Identification of very low-risk acute chest pain patients without troponin testing

BACKGROUND

The HEART Pathway combines a History ECG Age Risk factor (HEAR) score and serial troponins to risk stratify patients with acute chest pain. However, it is unclear whether patients with HEAR scores of <1 require troponin testing. The objective of this study is to measure the major adverse cardiac event (MACE) rate among patients with <1 HEAR scores and determine whether serial troponin testing is needed to achieve a miss rate <1%.

METHODS

A secondary analysis of the HEART Pathway Implementation Study was conducted. HEART Pathway risk assessments (HEAR scores and serial troponin testing at 0 and 3 hours) were completed by the providers on adult patients with chest pain from three US sites between November 2014 and January 2016. MACE (composite of death, myocardial infarction (MI) and coronary revascularisation) at 30 days was determined. The proportion of patients with HEAR scores of <1 diagnosed with MACE within 30 days was calculated. The impact of troponin testing on patients with HEAR scores of <1 was determined using Net Reclassification Improvement Index (NRI).

RESULTS

Providers completed HEAR assessments on 4979 patients and HEAR scores<1 occurred in 9.0% (447/4979) of patients. Among these patients, MACE at 30 days occurred in 0.9% (4/447; 95% CI 0.2% to 2.3%) with two deaths, two MIs and 0 revascularisations. The sensitivity and negative predictive value for MACE in the HEAR <1 was 97.8% (95%CI 94.5% to 99.4%) and 99.1% (95% CI 97.7% to 99.8%), respectively, and were not improved by troponin testing. Troponin testing in patients with HEAR <1 correctly reclassified two patients diagnosed with MACE, and was elevated among seven patients without MACE yielding an NRI of 0.9% (95%CI -0.7 to 2.4%).

CONCLUSION

These data suggest that patients with HEAR scores of 0 and 1 represent a very low-risk group that may not require troponin testing to achieve a missed MACE rate <1%. Trial registration number NCT02056964.

Use of the HEART Pathway with high sensitivity cardiac troponins: A secondary analysis

OBJECTIVES

The HEART Pathway combines a decision aid and serial contemporary cardiac troponin I (cTnI) measures to achieve >99% sensitivity for major adverse cardiac events (MACE) at 30days and early discharge rates >20%. However, the impact of integrating high-sensitivity troponin (hs-cTn) measures into the HEART Pathway has yet to be determined. In this analysis we compare test characteristics of the HEART Pathway using hs-cTnI, hs-cTnT, or cTnI.

DESIGN & METHODS

A secondary analysis of participants enrolled in the HEART Pathway RCT was conducted. Each patient was risk stratified by the cTn-HEART Pathway (Siemens TnI-Ultra at 0- and 3-h) and a hs-cTn-HEART Pathway using hs-cTnI (Abbott) or hs-cTnT (Roche) at 3-h. The early discharge rate, sensitivity, specificity, and negative predictive value (NPV) for MACE (death, myocardial infarction, or coronary revascularization) at 30days were calculated.

RESULTS

hs-cTnI measures were available on 133 patients. MACE occurred in 11/133 (8%) of these patients. Test characteristics for the HEART Pathway using serial cTnI vs 3hour hs-cTnI were the same: sensitivity (100%, 95%CI: 72-100%), specificity (49%, 95%CI: 40-58%), NPV (100%, 95%CI: 94-100%), and early discharge rate (45%, 95%CI: 37-54%). The HEART Pathway using hs-cTnT missed one MACE event (myocardial infarction): sensitivity (91%, 95%CI: 59-100%), specificity (48%, 95%CI: 39-57%), NPV (98%, 95%CI: 91-100%), and early discharge rate (45%, 95%CI: 37-54%).

CONCLUSIONS

There was no difference in the test characteristics of the HEART Pathway whether using cTnI or hs-cTnI, with both achieving 100% sensitivity and NPV. Use of hs-cTnT with the HEART Pathway was associated with one missed MACE.

Phagocytosis of spermatozoa by the rabbit vagina

Twenty-four hours after mating in the rabbit, numerous spermatozoa are observed attached to the surgace of the vaginal epithelium. Spermatozoa appear to be attached by their heads to microvilli of the simple columnar cells which compose the vaginal epithelium. Spermatozoa are taken up by the epithelial cells, and they are found within the cells in various stages of degeneration up to seven days after mating. Epithelial cells frequently appear to be filled with numerous vacuoles containing sperm components in various stages of degeneration. It is suggested that some property of the surface of sperm heads may render them particularly susceptible to phagocytosis. Phagocytosis of spermatozoa may not have long-term harmful effects for the epithelium since these epithelial cells presumably have a high rate of turnover.

The impact of emergency department overcrowding on resident education

BACKGROUND

Few studies have evaluated the effect of Emergency Department (ED) overcrowding on resident education.

OBJECTIVES

To determine the impact of ED overcrowding on Emergency Medicine (EM) resident education.

MATERIALS AND METHODS

A prospective cross-sectional study was performed from March to May 2009. Second- and third-year EM residents, blinded to the research objective, completed a questionnaire at the end of each shift. Residents were asked to evaluate the educational quality of each shift using a 10-point Likert scale. Number of patients seen and procedures completed were recorded. Responses were divided into ED overcrowding (group O) and non-ED overcrowding (group N) groups. ED overcrowding was defined as >2 h of ambulance diversion per shift. Questionnaire responses were compared using Mann-Whitney U tests. Number of patients and procedures were compared using unpaired T-tests.

RESULTS

During the study period, 125 questionnaires were completed; 54 in group O and 71 in group N. For group O, the median educational value score was 8 (interquartile range [IQR] 7-10), compared to 8 (IQR 8-10) for group N (p = 0.24). Mean number of patients seen in group O was 12.3 (95% confidence interval [CI] 11.4-13.2), compared to 13.9 (95% CI 12.7-15) in group N (p = 0.034). In group O, mean number of procedures was 0.9 (95% CI 0.6-1.2), compared to 1.3 (95% CI 1-1.6) in group N (p = 0.047).

CONCLUSIONS

During overcrowding, EM residents saw fewer patients and performed fewer procedures. However, there was no significant difference in resident perception of educational value during times of overcrowding vs. non-overcrowding.