Echocardiography in the evaluation of patients in chest pain units

Accuracy of Emergency Physicians for Detection of Regional Wall Motion Abnormalities in Patients With Chest Pain Without ST-Elevation Myocardial Infarction

OBJECTIVES

Our aim was to evaluate the accuracy of emergency physicians (EPs) in the detection of regional wall motion abnormalities (RWMAs) using focused cardiac ultrasound (FOCUS) in patients suspected of non-having ST-elevation myocardial infarction.

METHODS

We prospectively enrolled patients with chest pain. Three EPs underwent didactics and hands-on-training, of 3 hours each, by an experienced cardiologist, on detecting RWMAs using 2-dimensional echocardiography. They performed a FOCUS examination to evaluate for RWMAs and recorded the echo images. Our reference standard for the detection of RWMAs was accepted as a blinded cardiologist review of the prerecorded video clips. We calculated the corrected sample size and inter-rater agreement between the EPs (82 and 0.83, respectively). The analysis of the study was performed on 89 patients.

RESULTS

Eighty-nine patients with chest pain were screened. Emergency physicians demonstrated the detection of RWMAs with good sensitivity and even excellent specificity: 76.9% (95% confidence interval [CI], 56.4%- 91.0%) and 92.1% (95% CI, 82.4%-97.4%), respectively. The accuracy of FOCUS was 87.6% (95% CI, 79.0%-93.7%). The area under the curve from a receiver operating characteristic curve analysis, which evaluated the EPs' rate of detecting the presence or absence of RWMAs, was 0.845 (95% CI, 0.753-0.913).

CONCLUSIONS

Our study results suggest that EPs with training in bedside echocardiography can accurately rule in patients with RWMAs in suspected non-ST-elevation myocardial infarction cases.

A non-invasive nanoparticles for multimodal imaging of ischemic myocardium in rats

BACKGROUND

Ischemic heart disease (IHD) is the leading cause of morbidity and mortality worldwide, and imposes a serious economic load. Thus, it is crucial to perform a timely and accurate diagnosis and monitoring in the early stage of myocardial ischemia. Currently, nanoparticles (NPs) have emerged as promising tools for multimodal imaging, because of their advantages of non-invasion, high-safety, and real-time dynamic imaging, providing valuable information for the diagnosis of heart diseases.

RESULTS

In this study, we prepared a targeted nanoprobe (termed IMTP-Fe3O4-PFH NPs) with enhanced ultrasound (US), photoacoustic (PA), and magnetic resonance (MR) performance for direct and non-invasive visual imaging of ischemic myocardium in a rat model. This successfully designed nanoprobe had excellent properties such as nanoscale size, good stability, phase transformation by acoustic droplet vaporization (ADV), and favorable safety profile. Besides, it realized obvious targeting performance toward hypoxia-injured cells as well as model rat hearts. After injection of NPs through the tail vein of model rats, in vivo imaging results showed a significantly enhanced US/PA/MR signal, well indicating the remarkable feasibility of nanoprobe to distinguish the ischemic myocardium.

CONCLUSIONS

IMTP-Fe3O4-PFH NPs may be a promising nanoplatform for early detection of ischemic myocardium and targeted treatment under visualization for the future.

Echocardiography in Detecting Mechanical Complications in Acute Coronary Syndrome

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ACS encompasses a wide variety of complex symptoms and presentations.

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The use of echocardiography in ACS assists in early clinical decision-making.

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Echocardiography can aid in detecting early and late mechanical complications of ACS.

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Early detection of complications of ACS on echocardiography can improve outcomes.

Immediate Stress Echocardiography for Low-Risk Chest Pain Patients in the Emergency Department: A Prospective Observational Cohort Study

BACKGROUND

Evaluation and disposition of low-risk chest pain (CP) patients in the emergency department (ED) is time consuming and expensive. Low-risk CP often results in hospital admission to rule out myocardial infarction, which leads to additional costs and delays.

OBJECTIVE

Our aim was to assess whether an immediate exercise stress echocardiogram (IESE) in the ED will allow safe, efficient, and cost-effective evaluation and discharge of patients with low-risk CP.

METHODS

Low-risk CP patients (TIMI [Thrombolysis in Myocardial Infarction] score 0-1) presenting to the ED with normal electrocardiogram, no history of coronary artery disease, and negative troponin T received IESE. We followed these patients for major adverse cardiac events and compared them to a control cohort of similar-risk patients admitted with traditional care at 1 and 6 months.

RESULTS

We enrolled 216 patients, 117 IESE and 109 control. We obtained follow-up at 1 and 6 months in 94% of the IESE group and 88% in the control group. There was no difference in diagnostic catheterization or percutaneous coronary intervention between the 2 groups (6.0% and 1.7% vs. 6.4% and 1.8%; p = 0.89). Median time from triage to discharge was significantly shorter with IESE (572.6 min vs. 1466.0 min), resulting in significantly lower cost ($4380.50 vs. $6191.70). There were no adverse events related to IESE or early discharge.

CONCLUSIONS

In our study, IESE for low-risk CP patients presenting to the ED has the potential to be equally safe, more expeditious, and more cost effective than admission to an observation unit.

The Use of Echocardiography in Certified Chest Pain Units: Results from the German Chest Pain Unit Registry

OBJECTIVES

To analyze the current usage of transthoracic echocardiography (TTE) as a rapid, noninvasive tool in the early stratification of acute chest pain in certified German chest pain units (CPUs).

METHODS

A total of 23,997 patients were enrolled. Analyses comprised TTE evaluation rates in relation to clinical presentation, risk profile, left ventricular impairment, final diagnosis and invasive management. Critical times were assessed. Multivariable analyses for independent determinants for the use of TTE were performed.

RESULTS

TTE evaluation was available in CPUs in 70.1% of cases. It was associated with lower rates of invasive management in unstable angina pectoris (UAP) and with higher rates in patients with initially suspected non-cardiac origin of symptoms and/or reduced systolic function (p < 0.05). Non-ST-segment elevation acute coronary syndrome (NSTE-ACS) was an independent determinant favoring TTE evaluation [NSTE-myocardial infarction: odds ratio (OR) 1.62; UAP: OR 1.34; p < 0.001 for both]. Clinical signs of heart failure (OR 1.31; p < 0.001), referral by emergency medical service (OR 1.18; p < 0.001) and kidney failure (OR 1.16; p < 0.05) were independently associated with higher TTE rates. TTE did not delay door-to-balloon times.

CONCLUSIONS

About two thirds of the patients admitted to certified CPUs received TTE evaluation, with the highest rates being in ACS patients, and thereby providing diagnostic information supporting or refuting further invasive management.

Chest pain: coronary CT in the ER

Cardiac CT has developed into a robust clinical tool during the past 15 years. Of the fields in which the potential of cardiac CT has raised more interest is chest pain in acute settings. In fact, the possibility to exclude with high reliability obstructive coronary artery disease (CAD) in patients at low-to-intermediate risk is of great interest both from the clinical standpoint and from the management standpoint. Several other modalities, with or without imaging, have been used during the past decades in the settings of new onset chest pain or in acute chest pain for both diagnostic and prognostic assessment of CAD. Each one has advantages and disadvantages. Most imaging modalities also focus on inducible ischaemia to guide referral to invasive coronary angiography. The advent of cardiac CT has introduced a new practice diagnostic paradigm, being the most accurate non-invasive method for identification and exclusion of CAD. Furthermore, the detection of subclinical CAD and plaque imaging offer the opportunity to improve risk stratification. Moreover, recent advances of the latest generation CT scanners allow combining both anatomical and functional imaging by stress myocardial perfusion. The role of cardiac CT in acute settings is already important and will become progressively more important in the coming years.

Reliable exclusion of acute coronary syndrome among hospitalized patients with elevated troponin

BACKGROUND

Elevated cardiac troponin I (cTnI) occurs in acute coronary syndrome (ACS) as well as various scenarios not associated with ACS.

HYPOTHESIS

Simple clinical criteria can reliably exclude ACS among hospitalized patients with elevated cTnI.

METHODS

Records for patients hospitalized from January to April 2011 with elevated cTnI (>0.29 ng/dL) and an available echocardiogram were retrospectively reviewed. Patients with ST-segment elevation myocardial infarction were excluded. Based on available clinical data, patients were classified as having ACS or elevation of cTnI unrelated to ACS (non-ACS). Median follow-up was 365 days.

RESULTS

Of 265 records meeting inclusion criteria, 82 (31%) had ACS and 183 (69%) had non-ACS. In multivariable analysis, odds ratios for non-ACS were 7.6 (95% confidence interval [CI]: 3.8-15.3) for peak cTnI <2 ng/dL, 6.3 (95% CI: 3.1-13.0) for absent wall-motion abnormality, and 4.4 (95% CI: 2.2-8.6) for no prior coronary artery disease history. The area under the receiver operating curve for amodel using these 3 variables was 0.86, with a 98% negative predictive value for excluding ACS. Patients who met these 3 criteria had no ACS-related deaths over 1-year follow-up.

CONCLUSIONS

Hospitalized patients with peak Tn level<2 ng/dL, no prior history of coronary artery disease, and no new echocardiographic wall-motion abnormality appear to have a very low likelihood of ACS. Prospective validation of these results is needed to determine whether additional diagnostic testing could be safely avoided in hospitalized patients meeting these simple clinical criteria.

Physical Stress Echocardiography: Prediction of Mortality and Cardiac Events in Patients with Exercise Test showing Ischemia

Background

Studies have demonstrated the diagnostic accuracy and prognostic value of physical stress echocardiography in coronary artery disease. However, the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia is limited.

Objective

To evaluate the effectiveness of physical stress echocardiography in the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia.

Methods

This is a retrospective cohort in which 866 consecutive patients with exercise test positive for myocardial ischemia, and who underwent physical stress echocardiography were studied. Patients were divided into two groups: with physical stress echocardiography negative (G1) or positive (G2) for myocardial ischemia. The endpoints analyzed were all‑cause mortality and major cardiac events, defined as cardiac death and non-fatal acute myocardial infarction.

Results

G2 comprised 205 patients (23.7%). During the mean 85.6 ± 15.0-month follow-up, there were 26 deaths, of which six were cardiac deaths, and 25 non-fatal myocardial infarction cases. The independent predictors of mortality were: age, diabetes mellitus, and positive physical stress echocardiography (hazard ratio: 2.69; 95% confidence interval: 1.20 – 6.01; p = 0.016). The independent predictors of major cardiac events were: age, previous coronary artery disease, positive physical stress echocardiography (hazard ratio: 2.75; 95% confidence interval: 1.15 – 6.53; p = 0.022) and absence of a 10% increase in ejection fraction. All-cause mortality and the incidence of major cardiac events were significantly higher in G2 (p < 0. 001 and p = 0.001, respectively).

Conclusion

Physical stress echocardiography provides additional prognostic information in patients with exercise test positive for myocardial ischemia.

Role of imaging for acute chest pain syndromes

Acute chest pain suggestive of ischemic cardiac origin, with a normal or nondiagnostic electrocardiogram and negative initial cardiac markers for myocardial necrosis represent a significant diagnostic dilemma for clinicians. Multiple imaging modalities play a pivotal role in early diagnosis and safe discharge of these patients. In this review, we compare the current imaging modalities available for these patients including their diagnostic accuracy, feasibility, and cost effectiveness. Acute rest myocardial perfusion imaging significantly improves the clinical outcome in these patients and reduces the overall cost when incorporated into the decision making pathway. The choice of imaging modality recommended should be based on local institutional expertise and the overall clinical presentation. The imaging modality with high diagnostic accuracy and negative predictive value will provide for precise risk stratification which is important to clinical decision making, including patients who require admission to the hospital and those who can be safely discharged.

Clinical assessment of chest pain and guidelines for imaging

For many emergency facilities, risk assessment of patients with diffuse chest pain still poses a major challenge. In their currently valid recommendations, the international cardiological societies have defined a standardized assessment of the prognostically relevant cardiac risk criteria. Here the classic sequence of basic cardiac diagnostics including case history (cardiac risk factors), physical examination (haemodynamic and respiratory vital parameters), ECG (ST segment analysis) and laboratory risk markers (troponin levels) is paramount. The focus is, on the one hand, on timely indication for percutaneous catheterization, especially in patients at high cardiac risk with or without ST-segment elevation in the ECG, and, on the other hand, on the possibility of safely discharging patients with intermediate or low cardiac risk after non-invasive exclusion of a coronary syndrome. For patients in the intermediate or low risk group, physical or pharmacological stress testing in combination with scintigraphy, echocardiography or magnetic resonance imaging is recommended in addition to basic diagnostics. Moreover, the importance of non-invasive coronary imaging, primarily cardiac CT angiography (CCTA), is increasing. Current data show that in intermediate or low risk patients this method is suitable to reliably rule out coronary heart disease. In addition, attention is paid to the major differential diagnoses of acute coronary syndrome, particularly pulmonary embolism and aortic dissection. Here the diagnostic method of choice is thoracic CT, possibly also in combination with CCTA aiming at a triple rule-out.

Testing of low-risk patients presenting to the emergency department with chest pain: a scientific statement from the American Heart Association

The management of low-risk patients presenting to emergency departments is a common and challenging clinical problem entailing 8 million emergency department visits annually. Although a majority of these patients do not have a life-threatening condition, the clinician must distinguish between those who require urgent treatment of a serious problem and those with more benign entities who do not require admission. Inadvertent discharge of patients with acute coronary syndrome from the emergency department is associated with increased mortality and liability, whereas inappropriate admission of patients without serious disease is neither indicated nor cost-effective. Clinical judgment and basic clinical tools (history, physical examination, and electrocardiogram) remain primary in meeting this challenge and affording early identification of low-risk patients with chest pain. Additionally, established and newer diagnostic methods have extended clinicians' diagnostic capacity in this setting. Low-risk patients presenting with chest pain are increasingly managed in chest pain units in which accelerated diagnostic protocols are performed, comprising serial electrocardiograms and cardiac injury markers to exclude acute coronary syndrome. Patients with negative findings usually complete the accelerated diagnostic protocol with a confirmatory test to exclude ischemia. This is typically an exercise treadmill test or a cardiac imaging study if the exercise treadmill test is not applicable. Rest myocardial perfusion imaging has assumed an important role in this setting. Computed tomography coronary angiography has also shown promise in this setting. A negative accelerated diagnostic protocol evaluation allows discharge, whereas patients with positive findings are admitted. This approach has been found to be safe, accurate, and cost-effective in low-risk patients presenting with chest pain.

Emergency department and office-based evaluation of patients with chest pain

The management of patients with chest pain is a common and challenging clinical problem. Although most of these patients do not have a life-threatening condition, the clinician must distinguish between those who require urgent management of a serious problem such as acute coronary syndrome (ACS) and those with more benign entities who do not require admission. Although clinical judgment continues to be paramount in meeting this challenge, new diagnostic modalities have been developed to assist in risk stratification. These include markers of cardiac injury, risk scores, early stress testing, and noninvasive imaging of the heart. The basic clinical tools of history, physical examination, and electrocardiography are currently widely acknowledged to allow early identification of low-risk patients who have less than 5% probability of ACS. These patients are usually initially managed in the emergency department and transitioned to further outpatient evaluation or chest pain units. Multiple imaging strategies have been investigated to accelerate diagnosis and to provide further risk stratification of patients with no initial evidence of ACS. These include rest myocardial perfusion imaging, rest echocardiography, computed tomographic coronary angiography, and cardiac magnetic resonance imaging. All have very high negative predictive values for excluding ACS and have been successful in reducing unnecessary admissions for patients at low to intermediate risk of ACS. As patients with acute chest pain transition from the evaluation in the emergency department to other outpatient settings, it is important that all clinicians involved in the care of these patients understand the tools used for assessment and risk stratification.

Negative predictive value and potential cost savings of acute nuclear myocardial perfusion imaging in low risk patients with suspected acute coronary syndrome: a prospective single blinded study

BACKGROUND

Previous studies from the USA have shown that acute nuclear myocardial perfusion imaging (MPI) in low risk emergency department (ED) patients with suspected acute coronary syndrome (ACS) can be of clinical value. The aim of this study was to evaluate the utility and hospital economics of acute MPI in Swedish ED patients with suspected ACS.

METHODS

We included 40 patients (mean age 55 +/- 2 years, 50% women) who were admitted from the ED at Lund University Hospital for chest pain suspicious of ACS, and who had a normal or non-ischemic ECG and no previous myocardial infarction. All patients underwent MPI from the ED, and the results were analyzed only after patient discharge. The current diagnostic practice of admitting the included patients for observation and further evaluation was compared to a theoretical "MPI strategy", where patients with a normal MPI test would have been discharged home from the ED.

RESULTS

Twenty-seven patients had normal MPI results, and none of them had ACS. MPI thus had a negative predictive value for ACS of 100%. With the MPI strategy, 2/3 of the patients would thus have been discharged from the ED, resulting in a reduction of total hospital cost by some 270 EUR and of bed occupancy by 0.8 days per investigated patient.

CONCLUSION

Our findings in a Swedish ED support the results of larger American trials that acute MPI has the potential to safely reduce the number of admissions and decrease overall costs for low-risk ED patients with suspected ACS.

New methods for improved evaluation of patients with suspected acute coronary syndrome in the emergency department

This paper aims to identify and review new and unproven emergency department (ED) methods for improved evaluation in cases of suspected acute coronary syndrome (ACS). Systematic news coverage through PubMed from 2000 to 2006 identified papers on new methods for ED assessment of patients with suspected ACS. Articles found described decision support models, new ECG methods, new biomarkers and point-of-care testing, cardiac imaging, immediate exercise tests and the chest pain unit concept. None of these new methods is likely to be the perfect solution, and the best strategy today is therefore a combination of modern methods, where the optimal protocol depends on local resources and expertise. With a suitable combination of new methods, it is likely that more patients can be managed as outpatients, that length of stay can be shortened for those admitted, and that some patients with ACS can get earlier treatment.