A critical pathway for patients with acute chest pain and low risk for short-term adverse cardiac events: role of outpatient stress testing

Emergency Department Referral of Patients With Chest Pain for Noninvasive Cardiac Testing and 2-Year Clinical Outcomes

BACKGROUND

Noninvasive cardiac testing (NICT) has been associated with decreased long-term risks of major adverse cardiac events (MACEs) among emergency department patients at high coronary risk. It is unclear whether this association extends to patients without evidence of myocardial injury on initial ECG and cardiac troponin testing.

METHODS

A retrospective cohort study was conducted of patients presenting with chest pain between 2013 and 2019 to 21 emergency departments within an integrated health care system in Northern California, excluding patients with ST-segment-elevation myocardial infarction or myocardial injury by serum troponin testing. To account for confounding by indication, we grouped patient encounters by the NICT referral rate of the initially assigned emergency physician relative to local peers within discrete time periods. The primary outcome was MACE within 2 years. Secondary outcomes were coronary revascularization and MACE, inclusive of all-cause mortality. Associations between the NICT referral group (low, intermediate, or high) and outcomes were assessed using risk-adjusted proportional hazards methods with censoring for competing events.

RESULTS

Among 144 577 eligible patient encounters, the median age was 58 years (interquartile range, 48-68) and 57% were female. Thirty-day NICT referral was 13.0%, 19.9%, and 27.8% in low, intermediate, and high NICT referral groups, respectively, with a good balance of baseline covariates between groups. Compared with the low NICT referral group, there was no significant decrease in the adjusted hazard ratio of MACE within the intermediate (adjusted hazard ratio, 1.08 [95% CI, 1.02-1.14]) or high (adjusted hazard ratio, 1.05 [95% CI, 0.99-1.11]) NICT referral groups. Results were similar for MACE, inclusive of all-cause mortality, and coronary revascularization, as well as subgroup analyses stratified by estimated risk (history, electrocardiogram, age, risk factors, troponin [HEART] score: percent classified as low risk, 48.2%; moderate risk, 49.2%; and high risk, 2.7%).

CONCLUSIONS

Increases in NICT referrals were not associated with changes in the hazard of MACE within 2 years following emergency department visits for chest pain without evidence of acute myocardial injury. These findings further highlight the need for evidence-based guidance regarding the appropriate use of NICT in this population.

Major adverse cardiac event rates in moderate-risk patients: Does prior coronary disease matter?

BACKGROUND

Despite negative troponins and nonischemic electrocardiograms (ECGs), patients at moderate risk for acute coronary syndrome (ACS) are frequently admitted. The objective of this study was to describe the major adverse cardiac event (MACE) rate in moderate-risk patients and how it differs based on history of coronary artery disease (CAD).

METHODS

A secondary analysis of the HEART Pathway implementation study was conducted. This prospective interrupted time-series study accrued adults with possible ACS from three sites (November 2013-January 2016). This analysis excluded low-risk patients determined by emergency providers' HEART Pathway assessments. Non-low-risk patients were further classified as high risk, based on elevated troponin measures or ischemic ECG findings or as moderate risk, based on HEAR score ≥ 4, negative troponin measures, and a nonischemic ECG. Moderate-risk patients were then stratified by the presence or absence of prior CAD (MI, revascularization, or ≥70% coronary stenosis). MACE (death, myocardial infarction, or revascularization) at 30 days was determined from health records, insurance claims, and death index data. MACE rates were compared among groups using a chi-square test and likelihood ratios (LRs) were calculated.

RESULTS

Among 4,550 patients with HEART Pathway assessments, 24.8% (1,130/4,550) were high risk and 37.7% (1715/4550) were moderate risk. MACE at 30 days occurred in 3.1% (53/1,715; 95% confidence interval [CI] = 2.3% to 4.0%) of moderate-risk patients. Among moderate-risk patients, MACE occurred in 7.1% (36/508, 95% CI = 5.1% to 9.8%) of patients with known CAD versus 1.4% (17/1,207, 95% CI = 0.9% to 2.3%) in patients without known prior CAD (p < 0.0001). The negative LR for 30-day MACE among moderate-risk patients without prior CAD was 0.08 (95% CI = 0.05 to 0.12).

CONCLUSION

MACE rates at 30 days were low among moderate-risk patients but were significantly higher among those with prior CAD.

Higher intensity of 72-h noninvasive cardiac test referral does not improve short-term outcomes among emergency department patients with chest pain

BACKGROUND

It is unclear whether referral for cardiac noninvasive testing (NIT) following emergency department (ED) chest pain encounters improves short-term outcomes.

METHODS

This was a retrospective cohort study of patients presenting with chest pain, without ST-elevation myocardial infarction or myocardial injury by serum troponin testing, between 2013 and 2019 to 21 EDs within an integrated health care system. We examined the association between NIT referral (within 72 h of the ED encounter) and a primary outcome of 60-day major adverse cardiac events (MACE). Secondary outcomes were 60-day MACE without coronary revascularization (MACE-CR) and 60-day all-cause mortality. To account for confounding by indication for NIT, we grouped patient encounters into ranked tertiles of NIT referral intensity based on the likelihood of 72-h NIT referral associated with the initially assigned emergency physician, relative to local peers and within discrete time periods. Associations between NIT referral-intensity tertile and outcomes were assessed using risk-adjusted multivariable logistic regression.

RESULTS

Among 210,948 eligible patient encounters, 72-h NIT referral frequency was 11.9%, 18.3%, and 25.9% in low, intermediate, and high NIT referral-intensity encounters, respectively. Compared with the low referral-intensity tertile, there was a higher risk of 60-day MACE within the high referral-intensity tertile (odds ratio [OR] = 1.11, 95% confidence interval [CI] = 1.04 to 1.17) due to more coronary revascularizations without corresponding differences in MACE-CR or all-cause mortality. In analyses stratified by patients' estimated risk (HEART score; 50.5% lower risk, 38.7% moderate risk, 10.8% higher risk), the difference in 60-day MACE was primarily attributable to moderate-risk encounters (OR = 1.15, 95% CI = 1.08 to 1.24), with no differences among either lower- (OR = 1.10, 95% CI = 0.92 to 1.31) or higher- (OR = 1.01, 95% CI = 0.90 to 1.14) risk encounters.

CONCLUSION

Higher referral intensity for 72-h NIT was associated with higher risk of coronary revascularization but no difference in adverse events within 60 days. These findings further call into question the urgency of NIT among ED patients without objective evidence of myocardial injury.

Implementing "Chest Pain Pathway" Using Smartphone Messaging Application "WhatsApp" as a Corrective Action Plan to Improve Ischemia Time in "ST-Elevation Myocardial Infarction" in Primary PCI Capable Center "WhatsApp-STEMI Trial"

BACKGROUND

ST-elevation myocardial infarction (STEMI) is a life-threatening medical emergency that requires immediate medical attention. Each hospital should implement a clinical pathway with the main objective to reduce ischemia time from diagnosis to revascularization (because this has shown to save myocardial tissues and, subsequently, patients' lives), utilizing the most evidence-based approach and the most up-to-date management protocol. In this study, we aimed to assess the utility of structuring chest pain pathway (CPP) with the instantaneous case-by-case feedback protocol using WhatsApp and its impact on improving 2 major key performance indicators-the impact on initial emergency room (ER) door-to-electrocardiogram (ECG) time, and door-to-balloon time-in a predefined 6-month corrective action period.

METHODS

A prospective, quality improvement plan was set to reduce door-to-first-ECG and door-to-balloon times to less than 10 and 90 minutes, respectively, in all acute coronary syndrome cases (including STEMI cases), from August 2020 to April 30, 2021. Several measures were done to attain the goal, including strict compliance to CPP with documentation, ruling out possible mimickers, and reducing false activation and time delays in ER. Direct feedback on cases was provided using WhatsApp messaging app on smartphones; protocol and results of time lines were accessed by all healthcare providers associated with CPP, including ER nurses, ER doctors, Cardiology residents, specialists, Catheterization laboratory nurses, technicians, and interventionalists. Bimonthly meetings with all stake holders were reinforced, and minutes of meeting were reviewed and corrective actions were implemented the next day. On a daily basis, all cases were analyzed and tabulated by a dedicated nurse and a doctor from ER, and another nurse and doctor from the quality assurance department.

RESULTS

After a 6-month period of implementing improvement plan and sticking to a comprehensive chest pain clinical pathways strategy with a case-by-case review on a shared smartphone messaging application, the rate of door-to-first-ECG improved from 76% to 93% in patients with chest pain, and the door-to-balloon time targeting less than 90 minutes improved significantly from only 77% to 92% in STEMI patients. This was statistically significant with a P value of 0.0001 and 0.001, respectively, and the rate of false activation was reduced from 23% to 16% and 10% 3 and 6 months of time, respectively, with a significant P value of <0.01. Finally, a strict 100% rate of timely documentation on patients with chest pain was achieved.

CONCLUSIONS

An improvement plan of implementing the CPP, cut-time policy, and using smartphone WhatsApp messaging for a case-to-case instantaneous feedback has significantly improved key performance indicators and, subsequently, ischemia time in acute coronary syndrome patients (including STEMI patients) in 6 months time, indicating that this strategy works.

Clinically relevant adverse cardiovascular events in intermediate heart score patients admitted to the hospital following a negative emergency department evaluation

STUDY HYPOTHESIS

Study objective: To estimate the frequency of clinically relevant adverse cardiac events (CRACE) in patients admitted to the hospital for chest pain with an intermediate HEART score (4, 5, 6), non-diagnostic EKG, and a negative initial troponin.

METHODS

We conducted a retrospective analysis of all patients admitted to the University of Maryland Medical Center (UMMC) from May 2016 to May 2019 with an intermediate HEART score (4, 5, or 6), a non-diagnostic EKG, and a negative initial troponin. Our primary outcome was the rate of inpatient clinically relevant adverse cardiac events (CRACE), composite of life-threatening dysrhythmia, inpatient STEMI, cardiac or respiratory arrest, and all-cause mortality during hospitalization.

RESULTS

A total of 1118 patients met our inclusion criteria, 6 of whom had CRACE. Overall the rate of CRACE was 0.5% (95% CI, 0.2-1.2%). Six patients (0.5%, 95% CI, 0.2%-1.2%) experienced inpatient NSTEMIs, 212 patients (19%, 95% CI, 17-21%) underwent provocative testing during their inpatient stay, 5 patients received a stent or CABG, and 5 patients had false positive non-invasive testing and underwent a negative cardiac catheterization.

CONCLUSIONS

In this cohort of admitted patients with a documented intermediate-risk HEART score, nonischemic EKG, and negative initial troponin, the occurrence of CRACE during the index hospitalization was 0.5%.

Clinical effectiveness of an outpatient pathway for low-risk chest pain emergency department visits

BACKGROUND

Studies suggest that patients who present with atypical chest pain and are low or low-intermediate risk can safely undergo a rapid rule-out for cardiac ischemia with serial ECGs and cardiac biomarkers followed by additional testing as needed. We sought to evaluate a novel Emergency Department (ED) protocol for patients to undergo their additional functional testing as an outpatient.

METHODS

Patients presenting to the ED with atypical chest pain, normal ECG, and negative cardiac troponin felt to be low risk were referred for outpatient stress testing within 72 hours of presentation as part of a pilot program. We analyzed test characteristics, length of stay, and 30-day return visits to ED in the pilot group and compared results to a similar cohort assessed in the ED by a traditional chest pain observation protocol.

RESULTS

A total of 156 patients were included over a 5-month period with 29.5% not returning for testing. There was a 70% reduction in length of stay for outpatient stress test protocol patients. All-cause and cardiac return visits to the ED were not significantly different between the outpatient cohort and the traditional chest pain unit group and were reduced by 47 and 75%, respectively, in patients who completed their outpatient testing. The provisional injection protocol resulted in a 81% reduction in radiation exposure when compared to traditional MPI stress protocols due to a greater utilization of exercise treadmill tests without imaging.

CONCLUSION

Outpatient stress testing is a reliable alternative to traditional chest pain observation with a significantly shorter length of stay, reduced healthcare costs, and improved radiation safety profile for patients when compared to traditional inpatient observation.

High-Risk Chief Complaints I: Chest Pain-The Big Three (an Update)

Nontraumatic chest pain is a frequent concern of emergency department patients, with causes that range from benign to immediately life threatening. Identifying those patients who require immediate/urgent intervention remains challenging and is a high-risk area for emergency medicine physicians where incorrect or delayed diagnosis may lead to significant morbidity and mortality. This article focuses on the 3 most prevalent diagnoses associated with adverse outcomes in patients presenting with nontraumatic chest pain, acute coronary syndrome, thoracic aortic dissection, and pulmonary embolism. Important aspects of clinical evaluation, diagnostic testing, treatment, and disposition and other less common causes of lethal chest pain are also discussed.

A combined care model using early access to specialists off-hours to reduce cardiac admissions

Despite the implementation of diagnostic and treatment algorithms for many common cardiovascular (CV) complaints, identifying low- and intermediate-risk cardiac patients presenting to the emergency department (ED) who could be managed without hospital admission remains difficult. We hypothesized that the presence of an attending cardiologist in the ED after normal working hours would decrease the proportion of these patients admitted to the hospital. We conducted a retrospective study of patients seen in the ED with cardiac diagnoses identified by ICD-9 codes during the time period when the cardiologist was available (6 p.m.-midnight) compared with patients seen at other times of the day in the 12 months before and after the consultation program was implemented. The primary outcome was disposition at the time of discharge from the ED. Logistic regression was used to model the primary outcome. A difference-in-differences approach was used as the primary statistical test .Following the start of the consultation program, the odds of discharge home from the ED with or without observation increased (OR 1.69, 95% CI [1.45-1.96]). There was a significant interaction between pre-/post-intervention status and time of day in the odds of discharge home from the ED (P = 0.04) suggesting an association between the consultation program and disposition patterns that is independent of concurrent programs aimed to reduce utilization. An ED-based cardiology consultation program may reduce the need for inpatient stays by identifying low- to intermediate-risk patients safe for discharge from the ED with or without a period of active management/observation.

Symptoms Predictive of Acute Myocardial Infarction in the Troponin Era: Analysis From the TRAPID-AMI Study

The TRAPID-AMI (High Sensitivity Cardiac Troponin T assay for rapid Rule-out of Acute Myocardial Infarction) study evaluated a rapid "rule-out" acute myocardial infarction (AMI). We evaluated what symptoms were associated with AMI as part of a substudy of TRAPID-AMI. There were 1282 patients evaluated from 12 centers in Europe, the United States of America, and Australia from 2011 to 2013. Multiple symptom variables were prospectively obtained and evaluated for association with the final diagnosis of AMI. Multivariate logistic regression analysis was done, and odds ratios (OR) were calculated. There were 213/1282 (17%) AMIs. Four independent predictors for the diagnosis of AMI were identified: radiation to right arm or shoulder [OR = 3.0; confidence interval (CI): 1.8-5.0], chest pressure (OR = 2.5; CI: 1.3-4.6), worsened by physical activity (OR = 1.7; CI: 1.2-2.5), and radiation to left arm or shoulder (OR = 1.7; CI: 1.1-2.4). In the entire group, 131 (10%) had radiation to right arm or shoulder, 897 (70%) had chest pressure, 385 (30%) worsened with physical activity, and 448 (35%) had radiation to left arm or shoulder. Duration of symptoms was not predictive of AMI. There were no symptoms predictive of non-AMI. Relationship between AMI size and symptoms was also studied. For 213 AMI patients, cardiac troponins I values were divided into 4 quartiles. Symptoms including pulling chest pain, supramammillary right location, and right arm/shoulder radiation were significantly more likely to occur in patients with larger AMIs. In a large multicenter trial, only 4 symptoms were associated with the diagnosis of AMI, and no symptoms that were associated with a non-AMI diagnosis.

Implementation of an Early Discharge Protocol and Chest Pain Clinic for Low-Risk Chest Pain in the Emergency Department

BACKGROUND

Most of the patients presenting to emergency department with chest pain are at low risk of adverse events. Identifying high-risk patients can be challenging and resource intensive.

METHODS

We created a protocol to assist early discharge of low-risk adults with chest pain from emergency department. Also a chest pain clinic (CPC) was started for cardiology follow-up within 72 hours. In a retrospective cohort study, primary outcome of major adverse cardiac events (MACEs) of death, myocardial infarction, or revascularization was compared between CPC patients and those hospitalized for observation. In addition, rate of observation admissions and MACE were compared in the pre- and postintervention periods using piecewise regression and multiple logistic regression, respectively.

RESULTS

A total of 1422 patients were admitted for observation, and 290 were seen in CPC in the 1-year postintervention period. Thirty-day MACE was very low (0.7% in observation and 0.3% in CPC) postintervention. A total of 3637 patients were admitted for observation over the 2-year preintervention period. Thirty-day-adjusted MACE rate was not significantly different between pre- and postintervention periods (0.4% vs. 0.6%, P = 0.3), also monthly observation admissions did not change significantly; however, utilization of stress testing (57.2% vs. 41.0%, P < 0.001) and cardiac catheterization (2.3% vs. 1.6%, P = 0.036) was reduced.

CONCLUSION

Chest pain patients admitted for observation and risk stratification are at very low risk of 30-day MACE. An intervention based on a chest pain protocol and availability of early cardiology follow-up did not change the admission rate of these patients. This intervention was not associated with increased risk of adverse outcomes.

Evaluation of Outpatient Cardiac Stress Testing After Emergency Department Encounters for Suspected Acute Coronary Syndrome

STUDY OBJECTIVE

Professional guidelines recommend 72-hour cardiac stress testing after an emergency department (ED) evaluation for possible acute coronary syndrome. There are limited data on actual compliance rates and effect on patient outcomes. Our aim is to describe rates of completion of noninvasive cardiac stress testing and associated 30-day major adverse cardiac events.

METHODS

We conducted a retrospective analysis of ED encounters from June 2015 to June 2017 across 13 community EDs within an integrated health system in Southern California. The study population included all adults with a chest pain diagnosis, troponin value, and discharge with an order for an outpatient cardiac stress test. The primary outcome was the proportion of patients who completed an outpatient stress test within the recommended 3 days, 4 to 30 days, or not at all. Secondary analysis described the 30-day incidence of major adverse cardiac events.

RESULTS

During the study period, 24,459 patients presented with a chest pain evaluation requiring troponin analysis and stress test ordering from the ED. Of these, we studied the 7,988 patients who were discharged home to complete diagnostic testing, having been deemed appropriate by the treating clinicians for an outpatient stress test. The stress test completion rate was 31.3% within 3 days and 58.7% between 4 and 30 days, and 10.0% of patients did not complete the ordered test. The 30-day rates of major adverse cardiac events were low (death 0.0%, acute myocardial infarction 0.7%, and revascularization 0.3%). Rapid receipt of stress testing was not associated with improved 30-day major adverse cardiac events (odds ratio 0.92; 95% confidence interval 0.55 to 1.54).

CONCLUSION

Less than one third of patients completed outpatient stress testing within the guideline-recommended 3 days after initial evaluation. More important, the low adverse event rates suggest that selective outpatient stress testing is safe. In this cohort of patients selected for outpatient cardiac stress testing in a well-integrated health system, there does not appear to be any associated benefit of stress testing within 3 days, nor within 30 days, compared with those who never received testing at all. The lack of benefit of obtaining timely testing, in combination with low rates of objective adverse events, may warrant reassessment of the current guidelines.

Association of Early Stress Testing with Outcomes for Emergency Department Evaluation of Suspected Acute Coronary Syndrome

BACKGROUND

Professional society guidelines suggest early stress testing (within 72 hours) after an emergency department (ED) evaluation for suspected acute coronary syndrome (ACS). However, there is increasing concern that current practice results in over-testing without evidence of benefit. We test the hypothesis that early stress testing improves outcomes.

METHODS

We analyzed prospectively collected data from 9 EDs on patients with suspected ACS, 1999-2001. We excluded patients with an ED diagnosis of ACS. The primary outcome was 30-day major adverse cardiac events (MACEs), including all-cause death, acute myocardial infarction, and revascularization. We used the HEART score to determine pretest ACS risk (low, intermediate, and high). To mitigate potential confounding, patients with and without early stress testing were matched within pretest risk strata in a 1:2 ratio using propensity scores.

RESULTS

Of 7127 potentially eligible patients, 895 (13%) received early stress testing. The analytic cohort included 895 patients with early stress testing matched to 1790 without early stress testing. The overall 30-day MACE rate in both the source and analytic population was 3%. There were no baseline imbalances after propensity score matching (P > 0.1 for more than 30 variables). There was no association between early stress testing and 30-day MACE [odds ratio, 1.0; 95% confidence interval (CI), 0.6-1.7]. There was no effect modification by pretest risk (low: odds ratio, 1.0; 95% CI, 0.2-3.7; intermediate: 1.2; 95% CI, 0.6-2.6; high: 0.4; 95% CI, 0.1-1.6).

CONCLUSIONS

Early stress testing is not associated with reduced MACE in patients evaluated for suspected ACS. Early stress testing may have limited value in populations with low MACE rate.

The incremental value of stress testing in patients with acute chest pain beyond serial cardiac troponin testing

OBJECTIVE

In patients with acute chest pain and normal range cardiac troponin (cTn), accurate risk stratification for acute coronary syndrome is challenging. This study assesses the incremental value of stress testing to identify patients for angiography with a view to revascularisation.

METHODS

A single-centre observational study recruited patients with acute chest pain in whom serial cTn tests were negative and stress testing (exercise tolerance testing/dobutamine stress echocardiography) was performed. Stress tests were reported as negative, non-diagnostic or positive. The primary outcomes were revascularisation on index admission, or cardiac death and myocardial infarction over 1 year follow-up.

RESULTS

Of 749 patients recruited, 709 underwent exercise tolerance testing and 40 dobutamine stress echo of which 548 (73.2%) were negative, 169 (22.6%) were non-diagnostic and 32 (4.3%) were positive. Patients with positive tests (n=19 (59.4%)) were more likely to undergo index admission revascularisation than patients with non-diagnostic (n=15 (8.9%)) (p<0.001) tests who in turn were more likely undergo index admission revascularisation than those with negative tests (n=2 (0.4%)) (p<0.001). The risks of adverse events including cardiovascular death/acute myocardial infarction were low and were similar across stress test outcomes.

CONCLUSIONS

The incremental value of stress testing was the identification of an additional 34 (4.5% (95% CI 3.0% to 6.0%)) patients who underwent index admission revascularisation with a view to preventing future adverse events. Uncertainty in whether revascularisation prevents adverse events in patients with negative cTn means the choice to undertake stress testing depends on whether clinicians perceive value in identifying 4.5% of these patients for revascularisation.

CLINICAL TRIAL REGISTRATIONS

ACTRN1260900028327, ACTRN12611001069943.

Recommendations for the evaluation and management of observation services: a consensus white paper: the Society of Cardiovascular Patient Care

Observation Services (OS) was founded by emergency physicians in an attempt to manage "boarding" issues faced by emergency departments throughout the United States. As a result, OS have proven to be an effective strategy in reducing costs and decreasing lengths of stay while improving patient outcomes. When OS are appropriately leveraged for maximum efficiency, patients presenting to emergency departments with common disease processes can be effectively treated in a timely manner. A well-structured observation program will help hospitals reduce the number of inappropriate, costly inpatient admissions while avoiding the potential of inappropriate discharges. Observation medicine is a complicated multidimensional issue that has generated much confusion. This service is designed to provide the best possible patient care in a value-based purchasing environment where quality, cost, and patient satisfaction must continually be addressed. Observation medicine is a service not a status. Therefore, patients are admitted to the service as outpatients no matter whether they are placed in a virtual or dedicated observation unit. The key to a successful observation program is to determine how to maximize efficiencies. This white paper provides the reader with the foundational guidance for observational services. It defines how to set up an observational service program, which diagnoses are most appropriate for admission, and what the future holds. The goal is to help care providers from any hospital deliver the most appropriate level of treatment, to the most appropriate patient, in the most appropriate location while controlling costs.

Compliance with stress testing in patients discharged from the emergency department following a diagnosis of low-risk chest pain

OBJECTIVE

To determine rates of compliance with outpatient stress testing in patients with a diagnosis of low-risk chest pain, reasons for non-compliance and incidence of adverse cardiac events (ACE).

METHODS

This was a prospective study of 79 patients who were discharged from the emergency department with low-risk chest pain. Patients were followed-up by phone interview.

RESULTS

36.7% of patients completed EST within 30 days, 2.5% of patients completed their EST within the recommended 72 h. A lack of time was the most common reason for non-compliance and was seen in 32.0% of patients. 20% of ESTs were cancelled by the primary care physician (PCP). 12% of patients were non-compliant, as they believed the pain to be non-cardiac. There were no documented ACEs in the study.

CONCLUSIONS

Compliance with EST is poor in patients with low-risk chest pain. Non-compliance is related to a number of factors including work commitments, cancellation of studies by the PCP and patients beliefs about the nature of their chest pain.

The association between pretest probability of coronary artery disease and stress test utilization and outcomes in a chest pain observation unit

OBJECTIVES

Cardiology consensus guidelines recommend use of the Diamond and Forrester (D&F) score to augment the decision to pursue stress testing. However, recent work has reported no association between pretest probability of coronary artery disease (CAD) as measured by D&F and physician discretion in stress test utilization for inpatients. The author hypothesized that D&F pretest probability would predict the likelihood of acute coronary syndrome (ACS) and a positive stress test and that there would be limited yield to diagnostic testing of patients categorized as low pretest probability by D&F score who are admitted to a chest pain observation unit (CPU).

METHODS

This was a prospective observational cohort study of consecutively admitted CPU patients in a large-volume academic urban emergency department (ED). Cardiologists rounded on all patients and stress test utilization was driven by their recommendations. Inclusion criteria were as follows: age>18 years, American Heart Association (AHA) low/intermediate risk, nondynamic electrocardiograms (ECGs), and normal initial troponin I. Exclusion criteria were as follows: age older than 75 years with a history of CAD. A D&F score for likelihood of CAD was calculated on each patient independent of patient care. Based on the D&F score, patients were assigned a priori to low-, intermediate-, and high-risk groups (<10, 10 to 90, and >90%, respectively). ACS was defined by ischemia on stress test, coronary artery occlusion of ≥70% in at least one vessel, or elevations in troponin I consistent with consensus guidelines. A true-positive stress test was defined by evidence of reversible ischemia and subsequent angiographic evidence of critical stenosis or a discharge diagnosis of ACS. An estimated 3,500 patients would be necessary to have 1% precision around a potential 0.3% event rate in low-pretest-probability patients. Categorical comparisons were made using Pearson chi-square testing.

RESULTS

A total of 3,552 patients with index visits were enrolled over a 29-month period. The mean (±standard deviation [SD]) age was 51.3 (±9.3) years. Forty-nine percent of patients received stress testing. Pretest probability based on D&F score was associated with stress test utilization (p<0.01), risk of ACS (p<0.01), and true-positive stress tests (p=0.03). No patients with low pretest probability were subsequently diagnosed with ACS (95% CI=0 to 0.66%) or had a true-positive stress test (95% CI=0 to 1.6%).

CONCLUSIONS

Physician discretionary decision-making regarding stress test use is associated with pretest probability of CAD. However, based on the D&F score, low-pretest-probability patients who meet CPU admission criteria are very unlikely to have a true-positive stress test or eventually receive a diagnosis of ACS, such that observation and stress test utilization may be obviated.

Impact of clinical predictors and routine coronary artery disease testing on outcome of patients admitted to chest pain decision unit

BACKGROUND

Chest pain decision unit (CDU) evaluation of patients with acute chest pain (ACP) and nondiagnostic electrocardiogram (ECG) usually includes noninvasive testing for coronary artery disease (CAD).

HYPOTHESIS

CAD evaluation will not improve clinical outcome in low-risk ACP patients.

METHODS

We studied 459 adults admitted to CDU with ACP and no troponin release who underwent noninvasive CAD testing (stress testing in 396 and coronary computed tomographic angiography in 63). Multivariate logistic regression was used to determine predictors of adverse outcome over a 3-year follow-up period.

RESULTS

Initial noninvasive test was normal in 367 (80%) and abnormal (positive or indeterminate) in 92 (20%). A total of 42 (9%) patients underwent invasive coronary angiography, and 16 (3.5%) underwent revascularization. During follow-up, 33 patients had a total of 36 major clinical events: 12 revascularizations, 9 myocardial infarctions, and 15 deaths. Multivariate logistic regression analysis identified abnormal ECG (odds ratio [OR]: 2.7, P = 0.03), typical chest pain (OR: 3.8, P = 0.002), diabetes (OR: 4.1, P = 0.001), and known CAD (OR: 2.3, P = 0.03) as independent predictors for adverse outcome, but not noninvasive test result. Thus, in 187 patients with no high-risk features (41% of the cohort), the annualized event rate was 0.5%. In 272 patients with at least 1 high-risk feature, annualized event rates were 2.8% and 5.7% when noninvasive test was normal or abnormal, respectively (P = 0.04).

CONCLUSIONS

Clinical risk stratification allows identification of patients at low risk of adverse outcome over an intermediate period of follow-up. Noninvasive testing is not warranted in such patients.

Validation of high-sensitivity troponin I in a 2-hour diagnostic strategy to assess 30-day outcomes in emergency department patients with possible acute coronary syndrome

OBJECTIVES

The study objective was to validate a new high-sensitivity troponin I (hs-TnI) assay in a clinical protocol for assessing patients who present to the emergency department with chest pain.

BACKGROUND

Protocols using sensitive troponin assays can accelerate the rule out of acute myocardial infarction in patients with low-risk (suspected) acute coronary syndrome (ACS).

METHODS

This study evaluated 2 prospective cohorts of patients in the emergency department with ACS in an accelerated diagnostic pathway integrating 0- and 2-h hs-TnI results, Thrombolysis In Myocardial Infarction (TIMI) risk scores, and electrocardiography. Strategies to identify low-risk patients incorporated TIMI risk scores= 0 or ≤ 1. The primary endpoint was a major adverse cardiac event (MACE) within 30 days.

RESULTS

In the primary cohort, 1,635 patients were recruited and had 30-day follow-up. A total of 247 patients (15.1%) had a MACE. The finding of no ischemic electrocardiogram and hs-TnI ≤ 26.2 ng/l with the TIMI = 0 and TIMI ≤ 1 pathways, respectively, classified 19.6% (n = 320) and 41.5% (n = 678) of these patients as low risk; 0% (n = 0) and 0.8% (n = 2) had a MACE, respectively. In the secondary cohort, 909 patients were recruited. A total of 156 patients (17.2%) had a MACE. The TIMI = 0 and TIMI ≤ 1 pathways classified 25.3% (n = 230) and 38.6% (n = 351), respectively, of these patients as low risk; 0% (n = 0) and 0.8% (n = 1) had a MACE, respectively. Sensitivity, specificity, and negative predictive value for TIMI = 0 in the primary cohort were 100% (95% confidence interval [CI]: 98.5% to 100%), 23.1% (95% CI: 20.9% to 25.3%), and 100% (95% CI: 98.8% to 100%), respectively. Sensitivity, specificity, and negative predictive value for TIMI ≤ 1 in the primary cohort were 99.2 (95% CI: 97.1 to 99.8), 48.7 (95% CI: 46.1 to 51.3), and 99.7 (95% CI: 98.9 to 99.9), respectively. Sensitivity, specificity, and negative value for TIMI ≤ 1 in the secondary cohort were 99.4% (95% CI: 96.5 to 100), 46.5% (95% CI: 42.9 to 50.1), and 99.7% (95% CI: 98.4 to 100), respectively.

CONCLUSIONS

An early-discharge strategy using an hs-TnI assay and TIMI score ≤ 1 had similar safety as previously reported, with the potential to decrease the observation periods and admissions for approximately 40% of patients with suspected ACS. (Advantageous Predictors of Acute Coronary Syndromes Evaluation [APACE] Study, NCT00470587; A 2 hr Accelerated Diagnostic Protocol to Assess patients with chest Pain symptoms using contemporary Troponins as the only biomarker [ADAPT]: a prospective observational validation study, ACTRN12611001069943).

Improving stress testing compliance following chest pain presentations to the emergency department

OBJECTIVES

To determine whether a booked appointment time improves early outpatient exercise stress testing (EST) guideline adherence in patients discharged from the ED following assessment for possible acute coronary syndrome (ACS).

METHODS

In this pre and post study with a historical control group, patients classified as intermediate risk after negative ECG and serial troponin work-up for possible ACS were referred for EST. The intervention group were given an appointment time for EST at discharge, and the control group were given a referral but asked to book their own appointment. The primary outcome measure was the proportion in each group who attended for EST. Secondary outcomes were time to EST and rates of death, myocardial infarction and coronary revascularisation within 30 days in both groups. In addition, we explored reasons for non-attendance for EST for the intervention group.

RESULTS

There were 96 participants in the intervention group (mean age 55 ± 3 years) and 121 controls (mean age 62 ± 3 years). Seventy-two (75%) of the intervention group attended for EST compared with 38 (31%) of the control group, P < 0.001 after adjustment for differences in baseline variables. A poor understanding of the rationale for EST was a significant factor in patient non-attendance.

CONCLUSION

Pre-booked appointment times for EST improve timely attendance among patients discharged from the ED with intermediate-risk ACS. Compliance might improve further with patient education.

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.

The marriage of evidence and narrative: scientific nurturance within clinical practice

RATIONALE, AIMS AND OBJECTIVES

Published elaborations of evidence-based medicine (EBM) have failed to materially integrate the domains of interpersonal sensibility and relationship with tools intended to facilitate attention to biomedical research and knowledge within clinical practice. Furthermore, the elaboration of EBM skills has been confined to a narrow range of clinical research. As a result, crucial tools required to connect much clinically relevant research and practice remain hidden, and explorations of the deeper challenges faced by practitioners in their struggle to integrate sound science and shared clinical action remain elusive.

METHODS

We developed a model for scientifically informed, individualized, medical practice and learning that embraces the goals, resources and skills of EBM within a larger framework of practice defined by narrative process: 'attention', 'representation' and 'affiliation'. We drew from published elaborations of EBM, narrative medicine (NM) and the results of a project to develop tools for assessment of the cognitive skills embedded within a practice based EBM domain.

RESULTS

Within the resulting model, a tool of representation, whose components are Problem delineation, Actions, Choices and Targets, enables the clinical problem to be delineated and the patient and practitioner perspectives to be concretely defined with reference to four classes of clinical interaction: 'therapy', 'diagnosis', 'prognosis' and 'harm'. As a result, the 'information literacy' skills required to access, evaluate and apply clinical research using electronic resources are well defined but subordinated to shared appreciation of patient need. The model acknowledges the relevance of the full range and scope of scientifically derived medical knowledge.

CONCLUSION

A model based on integration of NM and EBM can lead to instructional tools that integrate clinical epidemiological knowledge with enforced consideration of differing patient and practitioner perspectives. It also may inform avenues for qualitative research into the processes through which such differing perspectives can be productively identified and shared.

Compliance with outpatient stress testing in low-risk patients presenting to the emergency department with chest pain

Recent evidence suggests that stress testing prior to emergency department (ED) release in low-risk chest pain patients identifies those who can be safely discharged home. When immediate stress testing is not feasible, rapid outpatient stress testing has been recommended. The objective of this study was to determine compliance rate and incidence of adverse cardiac events in patients presenting to the ED with low-risk chest pain referred for outpatient stress testing. Retrospective chart and social security death index review were conducted in 448 consecutive chest pain patients who presented to a university hospital and level I trauma center between April 30 and December 31, 2007. Patients were evaluated with an accelerated chest pain protocol defined as a 4-hour ED rule out and referral for outpatient stress testing within 72 hours of ED release. Only patients without known cardiac disease, a thrombolysis in myocardial infarction risk score ≤2, negative serial ECGs and cardiac biomarkers, and benign ED course were eligible for the protocol. Primary outcome measures included compliance with outpatient stress testing and documented 30-day incidence of adverse cardiac events following ED release. The social security death index was queried to determine 12-month incidence of all-cause mortality in enrolled patients. Logistic regression analysis of characteristics associated with outpatient stress test compliance was determined and incidence of adverse cardiac events in those who were and were not compliant with outpatient stress testing was compared. Significance was set at P < 0.05. A total of 188 patients (42%) completed outpatient stress testing, but only 27 (6%) completed testing within 72 hours of ED discharge. Compliance was correlated with insurance and race, but not patient age, gender, or thrombolysis in myocardial infarction risk score. No significant differences in adverse cardiac events were documented in patients who did and did not comply with outpatient stress testing. Compliance with outpatient stress testing is poor in low-risk chest pain patients following ED release. Despite poor compliance, the documented incidence of adverse cardiac events in this low-risk cohort was lower than that reported in patients with negative provocative testing prior to ED release.

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.

Numerical parameters and quality indicators in a medical emergency department

BACKGROUND

Despite calls for improved quality and efficiency in medical emergency departments, there exist hardly any quality indicators, and no methods of calculating efficiency have been published to date. The present study illustrates a means of presenting numerical parameters of a medical emergency department and of identifying potential quality indicators.

METHOD

Over a period of 12 months, all patient contacts of the medical emergency department in the University hospital of Erlangen were analyzed with respect to patient flow, diagnoses, and treatment units. The diagnostic agreement (DA) parameter was calculated from a systematic comparison of admitting and discharge diagnoses, and diagnostic efficiency (DE) was defined and calculated as the quotient of DA x100 divided by the length of stay in the emergency department.

RESULTS

Among the 6683 patients treated, 64.6% underwent further in-hospital care. The diagnostic spectrum of the outpatients differed markedly from that of the inpatients. Patients with diseases of the heart, gastrointestinal tract, and lungs were usually admitted to the hospital for further treatment. Patient contacts had a characteristic circadian and weekly rhythmic pattern. For the overall patient collective, the DA was 71%. The mean length of stay in the emergency department was 116 minutes, and the DE was therefore 0.61/min. The DA was highest (92%) among patients with atrial flutter or fibrillation, while the DE was highest (0.85/min) among patients with acute myocardial infarction. 14% of the patients required further treatment in intensive care.

CONCLUSION

Numerical parameters and quality indicators for a hospital emergency department can be presented in transparent fashion. DA and DE can be used as parameters for diagnosis-related and intradepartmental quality assessment.

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.

High-risk chief complaints I: chest pain--the big three

Chest pain is one of the most frequently seen chief complaints in patients presenting to emergency departments, and is considered to be a "high-risk" chief complaint. The differential diagnosis for chest pain is broad, and potential causes range from the benign to the immediately life-threatening. Although many (if not most) emergency department patients with chest pain do not have an immediately life-threatening condition, correct diagnoses can be difficult to make, incorrect diagnoses may lead to catastrophic therapies, and failure to make a timely diagnosis may contribute to significant morbidity and mortality. Several atraumatic "high-risk" causes of chest pain are discussed in this article, including myocardial infarction and ischemia, thoracic aortic dissection, and pulmonary embolism. Also included are brief discussions of tension pneumothorax, esophageal perforation, and cardiac tamponade.

CT of coronary artery disease

Technical innovation is rapidly improving the clinical utility of cardiac computed tomography (CT) and will increasingly address current technical limitations, especially the association of this test with relatively high levels of radiation. Guidelines for appropriate indications are in place and are evolving, with an increasing evidence base to ensure the appropriate use of this modality. New technologies and new applications, such as myocardial perfusion imaging and dual-energy CT, are being explored and are widening the scope of coronary CT angiography from mere coronary artery assessment to the integrative analysis of cardiac morphology, function, perfusion, and viability. The scientific evaluation of coronary CT angiography has left the stage of feasibility testing and increasingly, evidence-based data are accumulating on outcomes, prognosis, and cost-effectiveness. In this review, these developments will be discussed in the context of current pivotal transitions in cardiovascular disease management and their potential influence on the current role and future fate of coronary CT angiography will be examined.

Relationship between the QTc interval at hospital admission and the severity of the underlying ischaemia in low and intermediate risk people studied for acute chest pain

BACKGROUND

The corrected QT interval (QTc) is prolonged in the setting of acute coronary artery disease. However, very little data are available concerning the relationship between the QTc obtained soon after an episode of acute chest pain (ACHP) and the magnitude and severity of the myocardial ischaemia objectified in subsequent stress tests (STS).

METHODS

This was a prospective and observational study in which we investigated the relationship between the QTc determined on the hospital admission electrocardiogram (AQTc) using Bazett's formula and the results of the STS performed subsequently in 206 patients consecutively admitted to the Emergency Department for ACHP without persistent ST-elevation.

RESULTS

The mean AQTc was 456+/-60 ms. There were 88 (42%) individuals with a moderately or severely abnormal STS. The AQTc was longer in the patients with a moderately or severely abnormal STS: 490+/-52 versus 430+/-56 (p<0.001) and was correlated with the probability of the patient having a moderately or severely abnormal STS (c=0.84; p<0.001). The best cut-off point was 450 ms (sensitivity, specificity and negative predictive value: 81, 77 and 84 %). Patients with AQTc>or=450 had a higher frequency of moderately or severely abnormal STS (73 versus 16%; OR: 2.9; 95% CI: 2.1-4.1; p<0.001). After adjusting for age, sex, cardiac risk factors, cardiac history, QRS duration, ST-depression, troponin I release and pre-STS medical treatment, AQTc>or=450 remained as an independent predictor (OR: 12; 95% CI: 6-24; p<0.001).

CONCLUSIONS

In patients studied for ACHP, the QTc on the hospital admission electrocardiogram correlates with the underlying myocardial ischaemia. AQTc>or=450 ms selects a group of people at risk of presenting a moderately or severely abnormal STS, regardless of ST abnormalities and troponin release.

The role of cardiac risk factor burden in diagnosing acute coronary syndromes in the emergency department setting

STUDY OBJECTIVE

We seek to determine whether cardiac risk factor burden (defined as the number of conventional cardiac risk factors present) is useful for the diagnosis of acute coronary syndromes in the emergency department (ED) setting.

METHODS

This was a post hoc analysis of the Internet Tracking Registry of Acute Coronary Syndromes (i*trACS) registry, which had 17,713 ED visits for suspected acute coronary syndromes. First visit for US patients who were not cocaine or amphetamine users, who did not leave against medical advice, and for whom ECG and demographic data were complete were included. Acute coronary syndrome was defined by 30-day revascularization, diagnostic-related group codes, or death within 30 days, with positive cardiac biomarkers at index hospitalization. Cardiac risk factors were diabetes, hypertension, smoking, hypercholesterolemia, and family history of coronary artery disease. Cardiac risk factor burden was defined as the number of risk factors present. Because multiple logistic regression analysis revealed that age modified the relationship between cardiac risk factor burden and acute coronary syndromes, a stratified analysis was performed for 3 age categories: younger than 40, 40 to 65, and older than 65 years. Positive likelihood ratios and negative likelihood ratios with their 95% confidence intervals (CIs) were calculated for each total risk factor cutoff.

RESULTS

Of 10,806 eligible patients, 871 (8.1%) had acute coronary syndromes. In patients younger than 40 years, having no risk factors had a negative likelihood ratio of 0.17 (95% CI 0.04 to 0.66), and having 4 or more risk factors had a positive likelihood ratio of 7.39 (95% CI 3.09 to 17.67). In patients between 40 and 65 years of age, having no risk factors had a negative likelihood ratio of 0.53 (95% CI 0.40 to 0.71), and having 4 or more risk factors had a positive likelihood ratio of 2.13 (95% CI 1.66 to 2.73). In patients older than 65 years, having no risk factors had a negative likelihood ratio of 0.96 (95% CI 0.74 to 1.23), and having 4 or more risk factors had a positive likelihood ratio of 1.09 (95% CI 0.64 to 1.62).

CONCLUSION

Cardiac risk factor burden has limited clinical value in diagnosing acute coronary syndromes in the ED setting, especially in patients older than 40 years.