Acute ischemic syndromes. Chest pain center concept

New categorization of chest pain: noncardiac is in, atypical is out!

Chest pain poses a diagnostic challenge in the emergency department and requires a thorough clinical assessment. The traditional distinction between "atypical" and "typical" chest pain carries the risk of not addressing nonischemic clinical pictures. The newly conceived subdivision into cardiac, possibly cardiac, and (probably) noncardiac causes of the presenting symptom complex addresses a much more interdisciplinary approach to a symptom-oriented diagnostic algorithm. The diagnostic structures of the chest pain units in Germany do not currently reflect this. An adaptation should therefore be considered.

Cardiac, possible cardiac, and likely non-cardiac origin of chest pain : A hitherto underestimated parameter in German chest pain units

BACKGROUND

Current guidelines emphasize the diagnostic value of non-cardiac or possibly cardiac chest pain. The goal of this analysis was to determine whether German chest pain units (CPUs) adequately address conditions with "atypical" chest pain in existing diagnostic structures.

METHOD

A total of 11,734 patients from the German CPU registry were included. The analyses included mode of admission, critical time intervals, diagnostic steps, and differential diagnoses.

RESULTS

Patients with unspecified chest pain were younger, more often female, were less likely to have classic cardiovascular risk factors and tended to present more often as self-referrals. Patients with acute coronary syndrome (ACS) mostly had prehospital medical contact. Overall, there was no difference between these two groups regarding the time from the onset of first symptoms to arrival at the CPU. In the CPU, the usual basic diagnostic measures were performed irrespective of ACS as the primary working diagnosis. In the non-ACS group, further ischemia-specific diagnostics were rarely performed. Extra-cardiac differential diagnoses were not specified.

CONCLUSION

The establishment of broader awareness programs and opening CPUs for low-threshold evaluation of self-referring patients should be discussed. Regarding the rigid focus on the clarification of cardiac causes of chest pain, a stronger interdisciplinary approach should be promoted.

The Role of Nurses in a Chest Pain Unit

The chest pain unit (CPU) provides a service for patients at moderate-to-low risk for acute coronary syndrome (ACS). Although the number of CPUs has continued to grow worldwide, little has been written on the specific role and contribution of nursing in CPUs. The stay of patients in the CPU can be divided into six stages: triage, diagnosis, treatment, observation/monitoring, discharge, and follow-up. CPU nurses are in a unique position to promote evidence-based practice during all of these stages. Deeper insight into the unique role of nurses in CPUs will promote understanding of what type of knowledge, skills, and attitudes are required to provide the services that will contribute to improved quality of care for chest pain patients.

The evolution of chest pain pathways

Patients presenting to the emergency department with chest pain require prompt identification and referral, as early treatment of patients with an acute coronary syndrome (ACS) is crucial to decrease morbidity and mortality (Steurer et al, Emerg Med J. 2010;27:896-902). Although rule-in ACS is critical and time dependant, other difficulties arise during the rule-out ACS process (Steurer et al, Emerg Med J. 2010;27:896-902). Inappropriate discharge of patients with misdiagnosed acute myocardial infarction is associated with significant morbidity and mortality. Concerns relating to inappropriate discharge result in readmission with resultant lengthy hospital stays, high costs, and contribute to overcrowding and bed block (Amsterdam et al, J Am Coll Cardiol. 2002;40:251-256; Cardiol Clin. 2005;23:503-516; Furtado et al, Emerg Med. In press; Karlson, Am J Cardiol. 1991;68:171-175; Ng et al, Am J Cardiol. 2001;88:611-617; Ramakrishna et al, Mayo Clin Proc. 2005;80:322-329; Stowers, Crit Pathw Cardiol. 2003;2:88-94). The challenge of chest pain diagnosis has led to a number of associated problems within the health care system. The growing need for improvements in consistency of patient care, resource efficiency, and quality of patient healthcare has led to the development of chest pain pathways (Erhardt et al, Eur Heart J. 2002;23:1153-1176). The development and implementation of chest pain pathways is not without difficulties. These may arise from differences in the management approaches of health practitioners, poor adherence to guidelines, and concerns for costs. New procedures such as new cardiac injury markers, stress testing, and specialized chest pain units have led to a reduction in admission rates and length of stay, reduced costs, and a reduction of inappropriate discharge of patients with ischemic heart disease.

Cardiac CT in the emergency department

Current triage strategies are not effective in correctly identifying patients suffering from acute coronary syndrome (ACS). The diagnostic workup of patients presenting with acute chest pain continues to represent a major challenge for emergency department (ED) personnel. This statement holds especially true for patients with a low to intermediate likelihood for ACS. Taking current concepts for the diagnosis and management of patients presenting with acute chest pain to the ED into account, this article discusses the evidence and potential role of coronary computed tomography angiography to improve management of patients with possible ACS.

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.

Improved outcome in acute coronary syndrome by establishing a chest pain unit

AIMS

Chest pain units (CPUs) have been established to optimize treatment of patients with acute coronary syndrome (ACS) and to early and accurately discharge patients with non-coronary chest pain. The aim of this analysis was to elucidate whether treatment of ACS patients in the CPU versus emergency department (ED) has prognostic implications.

METHODS AND RESULTS

Patients presenting with suspected ACS to either the ED between August 2004 and June 2005 or the CPU between July 2005 and May 2006 were retrospectively analyzed. Of 1,796 included patients, 483 had the discharge diagnosis ACS. When compared to patients with exclusion of ACS they had more cardiovascular risk factors and higher troponin, creatinine and C-reactive protein levels (P < 0.001) at admission. Within 1 year, 37 patients of the ACS group suffered an event. Treatment in the ED compared with the CPU showed a significant increase in hazard ratio of 2.1 (P = 0.034) for the combined endpoint death, myocardial infarction and stroke, remaining unchanged after adjusting for confounders. Event-free 1-year survival was higher in CPU patients for the combined endpoint (P (logrank) = 0.02).

CONCLUSION

These results demonstrate a better 1-year prognosis for ACS patients treated in the CPU instead of the ED, therefore, supporting the idea to establish CPUs in Europe.

Design of a comprehensive chest pain initiative in an academic urban hospital

We describe the development and institution of an initiative based on a clinical diagnostic algorithm and treatment pathways, facilitated by cardiac nurse practitioners, for the treatment of the diverse group of patients with chest pain who seek treatment at our urban-based institution. We believe that our chest pain initiative incorporates previous strategies of rapid emergency department management with inpatient-based care while providing a framework for outpatient follow-up and secondary prevention. These strategies allow our hospital to meet its goals of providing chest pain patients with standardized, high-quality, and expeditious care, given the challenges faced by an academic urban hospital.

Frequency of acute coronary syndrome in patients with normal electrocardiogram performed during presence or absence of chest pain

OBJECTIVES

The authors hypothesized that patients with active chest pain at the time of a normal electrocardiogram (ECG) have a lower frequency of acute coronary syndrome (ACS) than patients being evaluated for chest pain but with no active chest pain at the time of a normal ECG. The study objective was to describe the association between chest pain in patients with a normal ECG and the diagnosis of ACS.

METHODS

This was a prospective observational study of emergency department (ED) patients with a chief complaint of chest pain and an initial normal ECG admitted to the hospital for chest pain evaluation over a 1-year period. Two groups were identified: patients with chest pain during the ECG and patients without chest pain during the ECG. Normal ECG criteria were as follow: 1) normal sinus rhythm with heart rate of 55-105 beats/min, 2) normal QRS interval and ST segment, and 3) normal T-wave morphology or T-wave flattening. "Normal" excludes pathologic Q waves, left ventricular hypertrophy, nonspecific ST-T wave abnormalities, any ST depression, and discrepancies in the axis between the T wave and the QRS. Patients' initial ED ECGs were interpreted as normal or abnormal by two emergency physicians (EPs); differences in interpretation were resolved by a cardiologist. ACS was defined as follows: 1) elevation and characteristic evolution of troponin I level, 2) coronary angiography demonstrating >70% stenosis in a major coronary artery, or 3) positive noninvasive cardiac stress test. Chi-square analysis was performed and odds ratios (ORs) are presented.

RESULTS

A total of 1,741 patients were admitted with cardiopulmonary symptoms; 387 met study criteria. The study group comprised 199 males (51%) and 188 females (49%), mean age was 56 years (range, 25-90 years), and 106 (27%) had known coronary artery disease (CAD). A total of 261 (67%) patients experienced chest pain during ECG; 126 (33%) patients experienced no chest pain during ECG. There was no difference between the two groups in age, sex, cardiac risk factors, or known CAD. The frequency of ACS for the total study group was 17% (67/387). There was no difference in prevalence of ACS based on the presence or absence of chest pain (16% or 42/261 vs. 20% or 25/126; OR = 0.77, 95% confidence interval = 0.45 to 1.33, p = 0.4).

CONCLUSIONS

Contrary to our hypothesis concerning patients who presented to the ED with a chief complaint of chest pain, our study demonstrated no difference in the frequency of acute coronary syndrome between patients with chest pain at the time of acquisition of a normal electrocardiogram and those without chest pain during acquisition of a normal electrocardiogram.

Exercise testing in chest pain units: rationale, implementation, and results

Chest pain units are now established centers for assessment of low-risk patients presenting to the emergency department with symptoms suggestive of acute coronary syndrome. Accelerated diagnostic protocols, of which treadmill testing is a key component, have been developed within these units for efficient evaluation of these patients. Studies of the last decade have established the utility of early exercise testing,which has been safe, accurate, and cost-effective in this setting. Specific diagnostic protocols vary, but most require 6 to 12 hours of observation by serial electrocardiography and cardiac injury markers to exclude infarction and high-risk unstable angina before proceeding to exercise testing. However, in the chest pain unit at UC Davis Medical Center,the approach includes "immediate" treadmill testing without a traditional process to rule out myocardial infarction. Extensive experience has validated this approach in a large, heterogeneous population. The optimal strategy for evaluating low-risk patients presenting to the emergency department with chest pain will continue to evolve based on current research and the development of new methods.

Point-of-Care Testing and Cardiac Biomarkers: The Standard of Care and Vision for Chest Pain Centers

Point-of-care testing (POCT) is defined as testing at or near the site of patient care. POCTdecreases therapeutic turnaround time (TTAT), increases clinical efficiency, and improves medical and economic outcomes. TTAT represents the time from test ordering to patient treatment. POC technologies have become ubiquitous in the United States, and, therefore,so has the potential for speed, convenience, and satisfaction, strong advantages for physicians, nurses, and patients in chest pain centers. POCT is applied most beneficially through the collaborative teamwork of clinicians and laboratorians who use integrative strategies, performance maps, clinical algorithms, and care paths (critical pathways). For example, clinical investigators have shown that on-site integration of testing for cardiac injury markers (myoglobin, creatinine kinase myocardial band [CKMB],and cardiac troponin I [cTnI]) in accelerated diagnostic algorithms produces effective screening, less hospitalization, and substantial savings. Chest pain centers, which now total over 150 accredited in the United States, incorporate similar types of protocol-driven performance enhancements. This optimization allows chest pain centers to improve patient evaluation, treatment, survival, and discharge. This article focuses on cardiac biomarker POCT for chest pain centers and emergency medicine.

Positive impact of an interdisciplinary chest pain initiative on traditionally underserved populations

BACKGROUND

We assessed the clinical impact of an interdisciplinary, cardiac nurse practitioner-facilitated chest pain (CP) initiative that stresses an early invasive approach for patients with CP with acute coronary syndromes in traditionally underserved patient populations, including females, blacks, Hispanics, and patients older than 60 years.

METHODS

Two groups of patients were identified: Pre-CP initiative (December 1999-February 2000) and post-CP initiative (December 2000-February 2001).

RESULTS

Analysis of 714 patients revealed significantly more cardiac diagnoses post-CP initiative (61% pre-CP initiative vs. 73% post-CP initiative, P = 0.002), including in patients with myocardial infarction (MI) who were older than 60 years, females, and Hispanics. There was a significant increase in rates of cardiac catheterizations within 1 week of admission (10.5% vs. 20.4%, P <0.001), including in Hispanics. For rates of coronary artery stenting and/or bypass grafting (CABG), there was also a significant increase post-CP initiative (2.5% vs. 10.1%, P = 0.0005), as well as for Hispanics. Length of stay was significantly reduced for patients older than 60 years (8.3 vs. 5.8 days, P = 0.002).

CONCLUSION

Establishment of an interdisciplinary, cardiac nurse practitioner-facilitated CP initiative is associated with improvement in several clinical processes and outcomes: increased cardiac disease diagnosis in females, Hispanics, and patients older than 60 years; increased rates of cardiac catheterizations in Hispanic patients, increased rates of coronary artery stenting and/or CABG, particularly in Hispanic patients; and decreased length of stay in patients older than 60 years. These data support a targeted interdisciplinary CP initiative as a strategy to systematically enhance access to cardiovascular diagnosis in underserved patient populations.

Electron beam computed tomography for assessment of patients presenting to the emergency department with chest pain

Electron beam computed tomography (EBCT) is a unique, noninvasive radiologic method capable of high-resolution imaging that is being increasingly used for evaluation of the cardiovascular system. Among its multiple applications, coronary artery calcium (CAC) imaging has attracted considerable attention because of the potential of this technique for early detection of coronary artery disease (CAD), the leading cause of mortality in our society. Although measurement of CAC has been primarily performed in the outpatient setting in both symptomatic and asymptomatic subjects, several studies have assessed the utility of the method to identify CAD in patients presenting to the emergency department with chest pain suggestive of myocardial ischemia but without objective evidence of the latter. This group comprises a majority of those presenting to the emergency department with chest pain, and their safe, accurate and cost-effective evaluation has been a continuing challenge.