Lack of association between left bundle-branch block and acute myocardial infarction in symptomatic ED patients

Objective

Guidelines recommend treating patients with a new or presumed new left bundle-branch block (LBBB) similar to those with an acute ST-segment elevation myocardial infarction. It is often unclear which emergency department (ED) patients with potentially ischemic symptoms actually have an acute myocardial infarction (AMI), even in the setting of LBBB. Our null hypothesis was that in ED patients with potential AMI, the presence of a new or presumed new LBBB would not predict an increased likelihood of AMI.

Methods

This was an observational cohort study. Patients older than 30 years who presented with chest pain or other ischemic equivalent and had an electrocardiogram (ECG) to evaluate potential acute coronary syndrome (ACS) were enrolled. Data collected include demographics, history, ECG, and cardiac markers. Electrocardiograms were classified according to the standardized guidelines, including LBBB not known to be old (new or presumed new LBBB), LBBB known to be old, or no LBBB. The hospital course was followed, and 30-day follow-up was performed on all patients. Our main outcome was AMI.

Results

There were 7937 visits (mean age, 54.3 ± 15 years, 57% female, 68% black): 55 had new or presumed new LBBB, 136 had old LBBB, and 7746 had no LBBB. The rate of AMI was not significantly different between the 3 groups (7.3% vs 5.2% vs 6.1%; P = .75). Revascularization (7.8% vs old 5.2% vs 4.3%; P = .04) and coronary artery disease were more common in patients with new or presumed new LBBB (19.2% vs 11.9% vs 10.1%; P = .0004).

Conclusions

Despite guideline recommendations that patients with potential ACS and new or presumed new LBBB should be treated similar to STEMI, ED patients with a new or presumed new LBBB are not at increased risk of AMI. In fact, the presence of LBBB, whether new or old, did not predict AMI. Caution should be used in applying recommendations derived from patients with definite AMI to ED patients with potential ACS that may or may not be sustaining an AMI.     

Diagnostic value of ischemia-modified albumin in patients with suspected acute coronary syndrome

Introduction

Ischemia-modified albumin (IMA) has been proposed as a useful rule-out marker for the diagnosis of acute coronary syndrome (ACS) in the emergency department. This study evaluated the ability of IMA to predict the acute myocardial infarction (AMI) diagnosis in a population of chest pain patients.

Methods

The study population comprised 107 subjects (men, 62%; women, 38%) admitted with suspected ACS. None of the patients had ST-segment elevations that qualified for immediate revascularization. Ischemia-modified albumin was determined from serum with albumin cobalt binding test (Inverness Medical Innovations Inc, Stirling, UK). Furthermore, cardiac troponin T, creatinine kinase MB mass, myoglobin, and heart-type fatty acid binding protein (H-FABP) were determined on arrival, after 6 to 9 hours, and after 12 to 24 hours. All patients had at least 2 blood samples taken to exclude/verify the AMI. AMI was defined by a cardiac troponin T level greater than 0.03 μg/L.

Results

Thirty-three percent of the patients (n = 35) had a final diagnosis of AMI. The sensitivity of admission IMA for a final diagnosis of ACS was 0.86 (95% confidence interval [95% CI], 0.69-0.95). Specificity was 0.49 (95% CI, 0.36-0.60). Negative predictive value was 0.88 (95% CI, 0.72-0.95). The optimal cutoff threshold derived from the receiver operating characteristics (ROC) curve (ROC analysis) was determined as 91 U/mL. The area under the ROC curve was 0.73. Ischemia-modified albumin did not, at any time, provide superior sensitivity or specificity compared with other biomarkers.We do not find the data supportive of IMA as a standard marker in the emergency department.     

Safety of a rapid diagnostic protocol with accelerated stress testing

Background

Most patients at low to intermediate risk for an acute coronary syndrome (ACS) receive a 12- to 24-hour “rule out.” Recently, trials have found that a coronary computed tomographic angiography–based strategy is more efficient. If stress testing were performed within the same time frame as coronary computed tomographic angiography, the 2 strategies would be more similar. We tested the hypothesis that stress testing can safely be performed within several hours of presentation.

Methods

We performed a retrospective cohort study of patients presenting to a university hospital from January 1, 2009, to December 31, 2011, with potential ACS. Patients placed in a clinical pathway that performed stress testing after 2 negative troponin values 2 hours apart were included. We excluded patients with ST-elevation myocardial infarction or with an elevated initial troponin. The main outcome was safety of immediate stress testing defined as the absence of death or acute myocardial infarction (defined as elevated troponin within 24 hours after the test).

Results

A total of 856 patients who presented with potential ACS were enrolled in the clinical pathway and included in this study. Patients had a median age of 55.0 (interquartile range, 48-62) years. Chest pain was the chief concern in 86%, and pain was present on arrival in 73% of the patients. There were no complications observed during the stress test. There were 0 deaths (95% confidence interval, 0%-0.46%) and 4 acute myocardial infarctions within 24 hours (0.5%; 95% confidence interval, 0.14%-1.27%). The peak troponins were small (0.06, 0.07, 0.07, and 0.19 ng/mL).

Conclusions

Patients who present to the ED with potential ACS can safely undergo a rapid diagnostic protocol with stress testing.     

Improving patient flow in acute coronary syndromes in the face of hospital crowding

Background

The current paradigm for the evaluation of patients with suspected acute coronary syndromes (ACS) in the emergency department (ED) is focused on the identification of patients with active underlying coronary disease. The majority of patients evaluated in the ED setting do not have active underlying cardiac disease.

Objective

To measure the effect of bedside point-of-care (POC) cardiac biomarker testing on telemetry unit admissions from the ED. Furthermore, to evaluate the effect telemetry admissions have on ED length of stay (LOS) and overall hospital LOS.

Methods

Primary data were collected over two 6-month periods in an urban teaching hospital ED. This was an observational cohort study conducted pre- and post- availability of a POC testing platform for cardiac biomarkers. Major measures included number of overall telemetry admissions, ED LOS, hospital LOS, and disposition. Patients were followed at 30 days for significant cardiac events, repeat ED visit or admission, and death.

Results

In the post-implementation period there was a 30% (95% confidence interval [CI] 36–44%) reduction in admissions to telemetry with a 33% (95% CI 26–39%) reduction in ED LOS and a 20% (95% CI 7–34%) reduction in hospital LOS. There was a 62% reduction in overall mortality between the pre-implementation period and the post-implementation period (p = 0.001).

Conclusion

The focused use of a rapid cardiac disposition protocol can dramatically impact resource utilization, expedite patient flow, and improve short-term outcomes for patients with suspected ACS.     

Utility of Observation Units for Young Emergency Department Chest Pain Patients

Background

Determining which patients presenting to the Emergency Department (ED) require further work-up for acute coronary syndrome (ACS) can be difficult. The utility of routine observation for cardiac testing in low-risk young adult patients has been questioned.

Study Objectives

We investigated the rate of positive findings yielded by routine cardiac observation unit work-up in patients aged 40 years or younger.

Methods

This was a retrospective observational cohort study of patients aged 18–40 years who were evaluated for ACS in an ED-based observation unit. Data were collected by trained abstractors from electronic medical records.

Results

A total of 362 patients met inclusion criteria. Of those, 239 received stress testing, yielding five positive and nine indeterminate results. One other patient had acute troponin elevation while under observation. The positive stress test patients and troponin-elevated patient underwent cardiac angiography. Only one positive stress test patient showed significant coronary stenosis and received coronary interventions. In follow-up data, one patient had an adverse cardiac outcome within 1 year of index visit, but no coronary interventions. Thus, only 3 patients had adverse cardiac events, with only one patient warranting intervention discovered by observation unit stress testing and a second via serial cardiac markers.

Conclusion

Routine observation of symptomatic young adults for ACS had low yield. Observation identified one patient with acute cardiac marker elevation and further stress testing identified only one patient with intervenable ACS, despite a high false-positive rate. This suggests that observation and stress testing should not be routinely performed in this demographic absent other high-risk features.     

Short- and long-term cardiac events in patients with chest pain with or without known existing coronary disease presenting normal electrocardiogram

Aim

The aim of this study is to evaluate incidence of adverse cardiac events in patients with chest pain with or without known existing coronary disease presenting normal electrocardiogram (ECG) and initial troponin.

Methods

Prospective, nonrandomized study enrolled low-risk patients with normal ECG and troponin on admission who underwent observation and/or stress testing by unstandardized clinical judgment. Patients who experienced recurrent angina or positive ECGs or positive troponins during observation or patients with positive stress testing were admitted; otherwise, they were discharged.

End Point

The end points are cardiac events at short- and long-term follow-up including cardiovascular death, myocardial infarction, unstable angina, and revascularization.

Results

Of 5656 patients considered, 1732 with ischemic ECG were initially admitted and, therefore, excluded from the analysis; 2860 with pleuritic chest pain and normal ECG were discharged; 1064 with visceral chest pain and normal ECG were enrolled. Patients with known coronary disease (45%) were older and likely presented known vascular disease. Patients with known vascular disease, older age, female sex, diabetes mellitus, and lower chest pain score were likely managed with observation. In patients with known coronary disease as compared with patients without, overall cardiac events account for 35% vs 14%, respectively (P < .001), as follows: in-hospital, 23% vs 10%, (P < .001); 1 month, 4% vs 2% (P = .133); and 9.9 ± 4.9 months, 8% vs 2%, respectively (P < .001).

Conclusions

One-third of patients with chest pain with known coronary disease, negative ECG, and biomarkers were subsequently found to have adverse cardiac events. The value of this research for an emergency medicine audience could be extended to all clinicians and general practitioners beyond cardiologists.     

Slow-onset and Fast-onset Symptom Presentations In Acute Coronary Syndrome (ACS): New Perspectives on Prehospital Delay in Patients with ACS

Background

Patient decision delay is the main reason why many patients fail to receive timely medical intervention for symptoms of acute coronary syndrome (ACS).

Study Objectives

This study examines the validity of slow-onset and fast-onset ACS presentations and their influence on ACS prehospital delay times. A fast-onset ACS presentation is characterized by sudden, continuous, and severe chest pain, and slow-onset ACS pertains to all other ACS presentations.

Methods

Baseline data pertaining to medical profiles, prehospital delay times, and ACS symptoms were recorded for all ACS patients who participated in a large multisite randomized control trial (RCT) in Dublin, Ireland. Patients were interviewed 2–4 days after their ACS event, and data were gathered using the ACS Response to Symptom Index.

Results

Only baseline data from the RCT, N = 893 patients, were analyzed. A total of 65% (n = 577) of patients experienced slow-onset ACS presentation, whereas 35% (n = 316) experienced fast-onset ACS. Patients who experienced slow-onset ACS were significantly more likely to have longer prehospital delays than patients with fast-onset ACS (3.5 h vs. 2.0 h, respectively, t = −5.63, df 890, p < 0.001). A multivariate analysis of delay revealed that, in the presence of other known delay factors, the only independent predictors of delay were slow-onset and fast-onset ACS (β = −.096, p < 0.002) and other factors associated with patient behavior.

Conclusion

Slow-onset ACS and fast-onset ACS presentations are associated with distinct behavioral patterns that significantly influence prehospital time frames. As such, slow-onset ACS and fast-onset ACS are legitimate ACS presentation phenomena that should be seriously considered when examining the factors associated with prehospital delay.     

Aspirin administration in ED patients who presented with undifferentiated chest pain: age,race, and sex effects

Study Objectives

The study aimed to determine whether aspirin therapy was differentially administered according to race, sex, or age in patients with undifferentiated chest pain who presented to an urban academic emergency department.

Methods

This was a prospective observational cohort study of patients older than 24 years who presented with chest pain between July 1999 and March 2002. Patients were grouped according to 30-day final diagnosis: acute myocardial infarction AMI, unstable angina USA, and non–acute coronary syndrome (ACS) chest pain. Data were analyzed using Fisher exact test and relative risk regression using the Gaussian estimating equation.

Results

There were 4478 patient visits, of which 4470 (99.8%) had complete information. Mean age was 52.2 ± 15.8 years. Blacks were 70.1% (n = 3135), whites 26.3% (n = 1175), and other 3.6% (n = 159). Women comprised 59.0% (n = 2639) of the patients. Aspirin therapy differed by race, sex, age, and final diagnosis. Patients who received aspirin were more likely to be white (60% vs 54%, P = .0009) or have an ACS diagnosis (82% vs 50%, P < .0001). By final diagnosis, there were no race, sex, or age differences for AMI or USA (P > .05). There were significant sex and age differences for non-ACS chest pain patients: men (53% vs 48% women, P = .0009) and older patients (>55 years, 60% vs 44% younger, P < .0001) had higher aspirin therapy due to administration to the patients with non-ACS chest pain.

Conclusion

For patients with undifferentiated chest pain, overall race, sex, and age differences were explained by higher rates of aspirin administered to older men with non-ACS chest pain.     

Evaluation of Global Registry of Acute Cardiac Events and Thrombolysis in Myocardial Infarction scores in patients with suspected acute coronary syndrome

Purposes

We aimed to evaluate the Global Registry of Acute Cardiac Events (GRACE) and Thrombolysis in Myocardial Infarction (TIMI) scores in patients with suspected but not proven acute coronary syndrome (ACS).

Basic procedures

We conducted a secondary analysis of data from the RATPAC trial. Standardized data were collected from 2263 patients presenting to 6 emergency departments with suspected but not proven ACS. Patients were followed up by record review and postal questionnaire at 30 and 90 days after recruitment to identify major adverse events, defined as death, emergency revascularization, life-threatening arrhythmia, hospitalization for ACS, or nonfatal acute myocardial infarction (AMI).

Main findings

Data were available for 2243 patients (mean age, 54.5 years; 58% male). The major adverse event rate was 43 (2%) of 2243 after 30 days and 62 (3%) of 2243 after 90 days. The c statistics for 30-day events were 0.717 (95% confidence interval [CI], 0.698-0.735) for GRACE and 0.682 (95% CI, 0.662-0.701) for TIMI. The corresponding 90-day c statistics were 0.726 (95% CI, 0.707-0.745) for GRACE and 0.693 (95% CI, 0.674-0.712) for TIMI. The c statistic for patient age alone was 0.656 for 30-day events and 0.689 for 90-day events.

Principal conclusions

The GRACE and TIMI scores are little better than age alone as predictors of major adverse events in patients with suspected but not proven ACS, and thus add little to prognostic assessment of such patients.     

Using extracorporeal membrane oxygenation to rescue acute myocardial infarction with cardiopulmonary collapse: The impact of early coronary revascularization

Objectives

To investigate the therapeutic impact of combining extracorporeal membrane oxygenation (ECMO) and early coronary revascularization on acute myocardial infarction (AMI)-induced cardiopulmonary collapse.

Materials and methods

This retrospective study included 35 consecutive patients rescued by ECMO for AMI-induced cardiopulmonary collapse in a single institution between June 2003 and December 2011. Coronary revascularization was performed soon after ECMO initiation. Percutaneous coronary intervention (PCI) was the primary revascularization strategy. Coronary artery bypass grafting (CABG) was performed if an unsuitable anatomy or unsatisfactory result of PCI. Comparisons were performed in groups with different revascularization strategies and outcomes.

Results

Among the 35 patients, 16 underwent CABG and 1 was bridged to transplant after CABG. Compared to patients receiving PCI only, the CABG group showed similar results in ECMO weaning (58% vs. 69%, p = 0.51), hospital discharge (32% vs. 50%, p = 0.27), and left ventricular ejection fraction before discharge (45% vs. 49%, p = 0.92). Regardless of revascularization strategies, this protocol achieved an ECMO-weaning rate of 63% and a hospital discharge rate of 40%. Dialysis-dependent acute renal failure (OR 5.4, 95% CI: 1.1–27.5) and profound anoxic encephalopathy (OR 5.4, 95% CI: 1.1–27.5) predicted non-weaning of ECMO. Age > 60 years (OR 7.3, 95% CI: 1.1–51.0) and profound anoxic encephalopathy (OR 24.6, 95% CI: 2.3–263.0) predicted in-hospital mortality. The major cardiovascular adverse effect (MACE)–free survival was 77% in the first year after discharge.

Conclusion

Early revascularization on ECMO is practical to preserve myocardial viability and bridge patients collapsing with AMI to recovery.     

A Case of Spontaneous Coronary Artery Dissection: It is Not Always Plaque Rupture

Background

Spontaneous coronary artery dissection (SCAD) is an extremely rare cause of acute coronary syndrome (ACS). Patients may present with a broad spectrum of clinical scenarios, ranging from angina pectoris to myocardial infarction, cardiogenic shock, and sudden death. Standard therapy has not been established; current treatments range from conservative management to percutaneous revascularization or coronary artery bypass surgery.

Objective

SCAD greatly mimics ACS, and this diagnosis should be considered when evaluating young patients who present with ACS with or without classical risk factors for coronary artery disease.

Case Report

We report a case of a 45-year old man who presented with chest pain typical of ACS. He had no risk factors except for a smoking history of 2.5 pack-years. Once the clinical findings suggested acute inferolateral myocardial infarction, the patient underwent emergent cardiac catheterization, which revealed left anterior descending coronary artery dissection. This in itself is not a common cause of inferolateral ST elevation changes on electrocardiogram.

Conclusion

This case highlights the fact that although SCAD is a rare entity, it is increasingly being recognized as a significant cause of ACS. Urgent angiography should be considered if SCAD is suspected, because early diagnosis and appropriate management significantly improve the outcome in these patients.     

Combining Thrombolysis in Myocardial Infarction risk score and clear-cut alternative diagnosis for chest pain risk stratification

Objective

The Thrombolysis in Myocardial Infarction (TIMI) risk score is a validated risk stratification tool useful in patients with definite and potential acute coronary syndromes (ACS) but does not identify patients safe for discharge from the emergency department (ED). Likewise, the use of a clear-cut alternative noncardiac diagnosis risk stratifies patients but does not identify a group safe for discharge. We hypothesized that the presence of an alternative diagnosis in patients with a TIMI risk score less than 2 might identify a cohort of patients safe for ED discharge.

Methods

In prospective cohort study, we enrolled ED patients with potential ACS. Data included demographics, medical history, components of the TIMI risk score, and whether the treating physician ascribed the condition to an alternative noncardiac diagnosis. Investigators followed the patients through the hospital course, and 30-day follow-up was done. The main outcome was 30-day death, myocardial infarction, or revascularization.

Results

A total of 3169 patients were enrolled (mean age, 53.6 ± 14 years; 45% men; 67% black). There were 991 patients (31%) with an alternative diagnosis, 980 patients with a TIMI risk score of 0, and 828 with a TIMI score of 1. At low levels of TIMI risk (<3), adding in a clinical impression of an alternative diagnosis did not reduce risk; at higher levels of TIMI risk, it did. The incidence of 30-day death, myocardial infarction, or revascularization for patients with a clinical impression of an alternative diagnosis and a TIMI score of 0 was 2.9% (95% confidence interval, 1.6%-5.0%).

Conclusions

The TIMI risk score stratifies patients with and without an alternative diagnosis. Unfortunately, patients with both a low TIMI risk score and a clinical impression of an alternative noncardiac diagnosis still have a risk of 30-day adverse events that is not low enough to allow safe discharge from the ED.     

The use of exercise stress testing for the management of low-risk patients with chest pain

Objective

This retrospective study assessed the contribution of exercise stress testing (EST) in the evaluation of patients with low risk for coronary heart disease who presented to the emergency department (ED) with chest pain.

Basic Procedures

The study included 175 patients who presented to the ED with chest pain and underwent EST between January 1, 2005, and November 30, 2006.

Main Findings

After the EST, 113 patients were discharged, and 62 were admitted. Exercise stress testing's positive predictive value for coronary artery disease among admitted patients was 35.7%, and sensitivity was 95.2%.Exercise stress testing's negative predictive value among discharged patients was 99.1%. None of the 113 discharged patients returned to the ED for cardiac reasons during the 30-day follow-up period.

Principal Conclusion

A chest pain unit or a parallel facility for evaluating patients with chest pain and with low risk for active coronary disease is necessary for detecting low-risk patients who eventually need cardiac intervention.     

Patient sex and quality of ED care for patients with myocardial infarction

Objective

The aim of the study was to assess the quality of care between male and female emergency department (ED) patients with acute myocardial infarction (AMI).

Methods

A 2-year retrospective cohort study of 2215 patients with AMI presenting immediately to 5 EDs from July 1, 2000, through June 30, 2002 was conducted. Data on patient characteristics, clinical presentation, and ED processes of care were obtained from chart and electrocardiogram reviews. Multivariable regression models were used to assess the independent association between sex and the ED administration of aspirin, β-blockers, and reperfusion therapy to eligible patients with AMI.

Results

There were 849 women and 1366 men in the study. Female patients were older than male patients (74.3 years for women vs 66.8 years for men, P < .001). Among ideal patients, women were less likely than men to receive aspirin (76.3% of women vs 81.3% of men, P < .01), β-blockers (51.7% of women vs 61.4% of men, P < .01), and reperfusion therapy (64.0% of women vs 72.8% of men, P < .05). However, after adjustment for age, there was no longer a significant relationship between sex and the use of aspirin (odds ratio [OR], 0.99; 95% confidence interval [CI], 0.95-1.03), β-blockers (OR, 0.94; 95% CI, 0.82-1.04), or reperfusion therapy (OR, 1.01; 95% CI, 0.89-1.09). In models adjusting for additional demographic, clinical, and hospital characteristics, there remained no association between sex and the processes of care.

Conclusion

Women with AMI treated in the ED have a lower likelihood of receiving aspirin, β-blocker, and reperfusion therapy. However, this association appears to be explained by the age difference between men and women with AMI. Although there are no apparent sex disparities in care, ED AMI management remains suboptimal for both sexes.     

Should creatine kinase-MB index be eliminated in patients with indeterminate troponins in the ED?

Objectives

The objective of this study is to determine whether creatine kinase-MB (CK-MB) index (CK-MBi) is useful in the evaluation of acute myocardial infarction (AMI) in patients with indeterminate troponin (Tn) in the emergency department (ED).

Methods

A retrospective cohort study was conducted of patients at an urban academic ED with over 55 000 annual visits who underwent Tn T (Roche, Indianapolis, IN) and CK-MB testing. One year of ED patients who had Tn testing were identified, and their corresponding CK-MBi was examined to find patients with indeterminate Tn (0.01-0.09) and positive CK-MBi (>6.0). Subsequent cardiac enzymes and hospital course were reviewed to identify patients diagnosed with AMI. A 95% confidence interval around point estimates were used in data analysis.

Results

Over 1 year, 11 718 initial Tn were identified. Indeterminate Tn was seen in 2512 cases. Of these, 28 had positive CK-MBi. Of the 28, 5 were judged by treating physicians to be having AMI and underwent cardiac catheterization. Of the 5 patients, 4 had subsequent positive Tns on serial enzyme testing. One of the patients thought to be having AMI had no coronary artery disease on catheterization. The rate of true positive CK-MBi with indeterminate Tn was 0.16% (95% confidence interval, 0.04%-0.41%).

Conclusion

Initial results identify rare cases of AMI where CK-MBi is positive in the setting of indeterminate Tn. However, most patients with indeterminate Tn and positive CK-MBi were not judged to be having AMI. In most cases, CK-MBi is not positive with indeterminate Tn and when positive more commonly confuses the picture. This suggests CK-MBi could be eliminated in patients with indeterminate Tns.     

Management of Acute Coronary Syndromes in Patients with Diabetes: Implications of the FREEDOM Trial

Background

Diabetes mellitus (DM) is a powerful independent risk factor for multivessel, diffuse coronary artery disease (CAD). The optimal coronary revascularization strategy in DM is not clearly defined, but past trials have suggested an advantage for coronary artery bypass grafting (CABG). Recently, the Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease (FREEDOM) trial found patients randomized to CABG had lower rates of death and myocardial infarction (MI) compared with those randomized to percutaneous coronary intervention (PCI).

Objective

This article reviews the contemporary management of patients with DM presenting with acute coronary syndromes, particularly ST-elevation MI, in the post-FREEDOM era.

Methods

We undertook a comprehensive review of published literature addressing trials in this field performed to address current knowledge both in the pre- and post-FREEDOM era.

Results

The implications of FREEDOM for patients with acute coronary syndrome are that CABG provides a significant benefit, compared with PCI with drug-eluting stents, to patients with DM and multivessel coronary artery disease; and that patients similar to those enrolled in FREEDOM should receive CABG in preference to PCI. The relevance of FREEDOM’s findings to the large proportion of patients who would not meet inclusion criteria—including patients with an acute coronary syndrome undergoing an early or emergent invasive strategy, remains uncertain.

Discussion

FREEDOM’s outcomes have generated uncertainty regarding best practice once thrombolysis in myocardial infarction grade 3 flow is re-established in patients with DM and multivessel disease. Current interventional guidelines recommend optimally treating the culprit artery; however, decisions made at the time of revascularization influence future revascularization strategies, particularly stent choice and resultant P2Y₁₂ receptor antagonist therapy. The preferred method for future revascularization may be questioned if the patient's residual coronary stenoses do not, post-PCI, meet the FREEDOM inclusion criteria, or where the left anterior descending artery is the infarct-related artery, and after left anterior descending artery PCI the patient would not receive an internal mammary graft. The management of residual disease and the preferred (further) revascularization strategy needs to be tested in an appropriately powered randomized trial.

Conclusions

The optimal revascularization strategy in patients with acute coronary syndrome, diabetes, and multivessel disease, in particular those with ST elevation, is unclear, and not guided by level A (or B) evidence. Currently CABG is favored over PCI, and an individually tailored, collaborative approach, guided by a multidisciplinary heart team, should be employed.     

ECG signs of acute myocardial ischemia in the prehospital setting of a suspected acute coronary syndrome and its association with outcomes

Aims

The aims of this study were (a) to determine the prehospital prevalence of electrocardiographic (ECG) signs of acute myocardial ischemia in patients with suspected acute coronary syndrome and (b) to describe the relationships between the various ECG patterns and the diagnosis of acute myocardial infarction (AMI) and outcomes.

Methods

Prospective cohort study using data from an interventional trial in acute chest pain patients transported by the emergency medical services. These patients were classified into 3 groups: patients with ECG showing signs of acute myocardial ischemia, patients with ECG showing other abnormal changes (bundle-branch block, pacemaker rhythm, Q-wave or T-wave inversion) and patients without significant pathologic findings. All P values are age-adjusted.

Results

Among 1546 patients, 312 (20%) had ECG signs of acute myocardial ischemia. Of them, 57% had a final diagnosis of AMI versus 26% of those with other abnormal ECGs and 12% of those with ECG without significant pathologic findings (P < .0001). In all, 53% of all AMI cases involved patients without ECG signs of acute myocardial ischemia. Although ECG signs of acute myocardial ischemia predicted heart failure and ventricular tachyarrhythmias both prior to and after hospital admission, there was no significant difference in 30-day mortality between the 3 patient groups (4.3%, 3.7%, and 1.2%, respectively, P = .11).

Conclusion

Among patients with a clinical suspicion of AMI in the prehospital setting, the prevalence of ECG signs suggesting AMI was low, as was the ability to identify AMI patients using ECG findings only. We therefore need better instruments in the prehospital triage of patients with acute chest pain.     

Diagnostic performance of initial salivary alpha-amylase activity for acute myocardial infarction in patients with acute chest pain

Background

To rule out acute myocardial infarction (AMI) in chest pain patients constitutes a diagnostic challenge to emergency department (ED) physicians.

Study Objectives

To evaluate the diagnostic value of measuring salivary alpha-amylase (sAA) activity for detecting AMI in patients presenting to the ED with acute chest pain.

Methods

sAA activity was measured in a prospective cohort of 473 consecutive adult patients within 4 h of onset of chest pain. Comparisons were made between patients with a final diagnosis of AMI and those with non-AMI. Univariate analysis and multiple logistic regression model were used to identify independent clinical predictors of AMI.

Results

Initial sAA activity in the AMI group (n = 85; 266 ± 127.6 U/mL) was significantly higher than in the non-AMI group (n = 388; 130 ± 92.8 U/mL, p < 0.001). sAA activity levels were also significantly higher in patients with ST elevation AMI (n = 53) compared to in those with non-ST elevation AMI (n = 32) (300 ± 141.1 vs. 210 ± 74.1 U/mL, p < 0.001). The area under the receiver operating characteristic curve of sAA activity for predicting AMI in patients with acute chest pain was 0.826 (95% confidence interval [CI] 0.782–0.869), with diagnostic odds ratio 10.87 (95% CI 6.16–19.18). With a best cutoff value of 197.7 U/mL, the sAA activity revealed moderate sensitivity and specificity as an independent predictor of AMI (78.8% and 74.5%).

Conclusions

High initial sAA activity is an independent predictor of AMI in patients presenting to the ED with chest pain.     

Heart-type fatty acid binding protein and the diagnosis of acute coronary syndrome in the ED

Background

In combination with cardiac troponin, heart-type fatty acid binding protein (h-FABP)—a biomarker of myocardial necrosis—offers the possibility of rapidly eliminating the diagnosis of acute myocardial infarction (AMI).

Objective

The main objective of this study was to assess the incremental value of h-FABP to cardiac troponin for a rapid elimination of AMI, according to the pretest probability (PTP) of AMI.

Methods

In consecutive patients presenting to emergency departments (ED) with chest pain less than 6 hours suggestive of AMI, h-FABP levels were measured, blinded to the ED physicians, who were asked to quote the PTP of AMI. The discharge diagnosis was adjudicated by 2 independent experts, blind to the h-FABP level.

Results

Three hundred seventeen patients (mean age of 57 years) were included in whom 149 had (47%) low, 117 (37%) moderate, and 51 (16%) high PTP. The final diagnosis was AMI in 45 patients (14%), including 16 STEMIs (5%). The negative predictive value for diagnostic elimination of AMI of an h-FABP less than 3 μg/L, combined with a negative cTnI was not higher than that of cardiac troponin I (cTnI) alone (96% [95% confidence interval, 93%-98%] vs 95% [93%-98%]), regardless of the PTP). Even in the low-PTP group, we did not demonstrate a significant improvement in negative predictive value with the addition of h-FABP, compare with that of cTnI alone (100% [97%-100%] vs 99% [96%-100%]).

Conclusion

In triage of patients with chest pain, use of h-FABP does not provide useful additional information to cTnI for excluding the diagnosis of ST-elevation myocardial infarction and non–ST-elevation myocardial infarction diagnosis, whatever the PTP.