To Treat or Not to Treat: Ethics of Management of Refractory Status Myoclonus Following Pediatric Anoxic Brain Injury

The development of status myoclonus (SM) in a postcardiac arrest patient has historically been thought of as indicative of not only a poor neurologic outcome but of neurologic devastation. In many instances, this may lead clinicians to initiate conversations about withdrawal of life sustaining therapies (WLST) regardless of the time from return of spontaneous circulation (ROSC). Recent studies showing a percentage of patients may make a good recovery has called into question whether a self-fulfilling prophecy has developed where the concern for a poor neurologic outcome leads clinicians to prematurely discuss WLST. The issue is only further complicated by changing terminology, lack of neuro-axis localization, and limited data regarding association with electroencephalogram (EEG) characteristics, all of which could aid in the understanding of the severity of neurologic injury associated with SM. Here we review the initial literature reporting SM as indicative of poor neurologic outcome, the studies that call this into question, the various definitions of SM and related terms as well as data regarding association with EEG backgrounds. We propose that improved prognostication on outcomes results from combining the presence of SM with other clinical variables (eg EEG patterns, MRI findings, and clinical exam). We discuss the ethical implications of using SM as a prognostic tool and its impact on decisions about life-sustaining care in children following cardiac arrest. We advocate for prognostication efforts to be delayed for at least 72 hours following ROSC and thus to treat SM in those early hours and days.

Bi-allelic CAMSAP1 variants cause a clinically recognizable neuronal migration disorder

Non-centrosomal microtubules are essential cytoskeletal filaments that are important for neurite formation, axonal transport, and neuronal migration. They require stabilization by microtubule minus-end-targeting proteins including the CAMSAP family of molecules. Using exome sequencing on samples from five unrelated families, we show that bi-allelic CAMSAP1 loss-of-function variants cause a clinically recognizable, syndromic neuronal migration disorder. The cardinal clinical features of the syndrome include a characteristic craniofacial appearance, primary microcephaly, severe neurodevelopmental delay, cortical visual impairment, and seizures. The neuroradiological phenotype comprises a highly recognizable combination of classic lissencephaly with a posterior more severe than anterior gradient similar to PAFAH1B1(LIS1)-related lissencephaly and severe hypoplasia or absence of the corpus callosum; dysplasia of the basal ganglia, hippocampus, and midbrain; and cerebellar hypodysplasia, similar to the tubulinopathies, a group of monogenic tubulin-associated disorders of cortical dysgenesis. Neural cell rosette lineages derived from affected individuals displayed findings consistent with these phenotypes, including abnormal morphology, decreased cell proliferation, and neuronal differentiation. Camsap1-null mice displayed increased perinatal mortality, and RNAScope studies identified high expression levels in the brain throughout neurogenesis and in facial structures, consistent with the mouse and human neurodevelopmental and craniofacial phenotypes. Together our findings confirm a fundamental role of CAMSAP1 in neuronal migration and brain development and define bi-allelic variants as a cause of a clinically distinct neurodevelopmental disorder in humans and mice.

Macroperiodic Oscillations Are Associated With Seizures Following Acquired Brain Injury in Young Children

PURPOSE

Seizures occur in 10% to 40% of critically ill children. We describe a phenomenon seen on color density spectral array but not raw EEG associated with seizures and acquired brain injury in pediatric patients.

METHODS

We reviewed EEGs of 541 children admitted to an intensive care unit between October 2015 and August 2018. We identified 38 children (7%) with a periodic pattern on color density spectral array that oscillates every 2 to 5 minutes and was not apparent on the raw EEG tracing, termed macroperiodic oscillations (MOs). Internal validity measures and interrater agreement were assessed. We compared demographic and clinical data between those with and without MOs.

RESULTS

Interrater reliability yielded a strong agreement for MOs identification (kappa: 0.778 [0.542-1.000]; P < 0.0001). There was a 76% overlap in the start and stop times of MOs among reviewers. All patients with MOs had seizures as opposed to 22.5% of the general intensive care unit monitoring population ( P < 0.0001). Macroperiodic oscillations occurred before or in the midst of recurrent seizures. Patients with MOs were younger (median of 8 vs. 208 days; P < 0.001), with indications for EEG monitoring more likely to be clinical seizures (42 vs. 16%; P < 0.001) or traumatic brain injury (16 vs. 5%, P < 0.01) and had fewer premorbid neurologic conditions (10.5 vs. 33%; P < 0.01).

CONCLUSIONS

Macroperiodic oscillations are a slow periodic pattern occurring over a longer time scale than periodic discharges in pediatric intensive care unit patients. This pattern is associated with seizures in young patients with acquired brain injuries.

A Virtual Community of Practice: An International Educational Series in Pediatric Neurocritical Care

Pediatric neurocritical care (PNCC) is a rapidly growing field. Challenges posed by the COVID-19 pandemic on trainee exposure to educational opportunities involving direct patient care led to the creative solutions for virtual education supported by guiding organizations such as the Pediatric Neurocritical Care Research Group (PNCRG). Our objective is to describe the creation of an international, peer-reviewed, online PNCC educational series targeting medical trainees and faculty. More than 1600 members of departments such as pediatrics, pediatric critical care, and child neurology hailing from 75 countries across six continents have participated in this series over a 10-month period. We created an online educational channel in PNCC with over 2500 views to date and over 130 followers. This framework could serve as a roadmap for other institutions and specialties seeking to address the ongoing problems of textbook obsolescence relating to the rapid acceleration in knowledge acquisition, as well as those seeking to create new educational content that offers opportunities for an interactive, global audience. Through the creation of a virtual community of practice, we have created an international forum for pediatric healthcare providers to share and learn specialized expertise and best practices to advance global pediatric health.

Continuous Electroencephalography Monitoring in Critically Ill Infants and Children

Continuous video electroencephalography (CEEG) monitoring of critically ill infants and children has expanded rapidly in recent years. Indications for CEEG include evaluation of patients with altered mental status, characterization of paroxysmal events, and detection of electrographic seizures, including monitoring of patients with limited neurological examination or conditions that put them at high risk for electrographic seizures (e.g., cardiac arrest or extracorporeal membrane oxygenation cannulation). Depending on the inclusion criteria and clinical characteristics of the population studied, the percentage of pediatric patients with electrographic seizures varies from 7% to 46% and with electrographic status epilepticus from 1% to 23%. There is also evidence that epileptiform and background CEEG patterns may provide important information about prognosis in certain clinical populations. Quantitative EEG techniques are emerging as a tool to enhance the value of CEEG to provide real-time bedside data for management and prognosis. Continued research is needed to understand the clinical value of seizure detection and identification of other CEEG patterns on the outcomes of critically ill infants and children.

Adaptive functioning in children with neurofibromatosis type 1: relationship to cognition, behavior, and magnetic resonance imaging

AIM

To characterize the adaptive behavior profile of children with neurofibromatosis type 1 (NF1) and determine its relationship to neuropsychological functioning and non-neoplastic T2-weighted hyperintense brain lesions on brain magnetic resonance imaging (MRI).

METHOD

In this cross-sectional study, we retrospectively reviewed neuropsychological reports from 104 children with NF1 (56 males, 48 females; mean age 10y 4mo; standard deviation [SD] 3y 4mo; range 3y 5mo-17y 6mo), and extracted data from a range of cognitive and behavioral measures, including the Adaptive Behavior Assessment System (ABAS). Brain MRI was retrospectively reviewed in 42 individuals.

RESULTS

Adaptive Behavior Assessment System scores were continuously distributed and pathologically shifted by 0.79 to 1.26SD across Conceptual, Social, and Practical domains, and 46.5% of individuals had a composite score in the borderline or impaired range. Impairment in adaptive functioning was correlated with deficits in executive function (r=-9.543, p<0.001), externalizing problems (r=-0.366, p<0.001), and attention (r=-9.467, p=0.001). Cluster analysis revealed three distinct phenotypic subgroups, one of which exhibited normal cognitive ability, but impaired adaptive functioning, with persistent deficits in executive function, behavioral problems, and attention-deficit/hyperactivity disorder symptomatology. There was no relationship between ABAS scores and the number or location of unidentified bright objects.

INTERPRETATION

Adaptive functioning deficits are common among children with NF1 and are associated with impairment in other cognitive/behavioral domains, independent of general cognitive ability.

WHAT THIS PAPER ADDS

Deficits in adaptive behavior are common in children with neurofibromatosis type 1 (NF1). Poor adaptive functioning is associated with impairments in executive function, externalizing behaviors, and attention, regardless of cognitive ability. The presence or location of unidentified bright objects do not predict adaptive behavior skills in children with NF1.

Increased prevalence of brain tumors classified as T2 hyperintensities in neurofibromatosis 1

Background

We sought to define the radiologic features that differentiate neoplastic from non-neoplastic T2 hyperintensities (T2Hs) in neurofibromatosis type 1 (NF1) and identify those lesions most likely to require oncologic surveillance.

Methods

We conducted a single-center retrospective review of all available brain MRIs from 68 children with NF1 (n = 190) and 46 healthy pediatric controls (n = 104). All T2Hs identified on MRI were characterized based on location, border, shape, degree of T1 hypointensity, and presence of mass effect or contrast enhancement, and subsequently classified using newly established radiologic criteria as either unidentified bright objects (UBOs) or probable tumors. Lesion classification was pathologically confirmed in 10 NF1 cases.

Results

T2Hs were a highly sensitive (94.4%; 95% confidence interval [CI] 86.4%-98.5%) and specific (100.0%; 95% CI 92.3%-100.0%) marker for the diagnosis of NF1. UBOs constituted the majority of T2Hs (82%) and were most frequently located in cerebellar white matter, medial temporal lobe, and thalamus, where they were more likely than probable tumors to be bilateral (p < 0.001) and have nondiscrete borders (p < 0.001). Surprisingly, 57% of children with T2Hs harbored lesions classified as probable tumors, and 28% of children with probable tumors received treatment. In contrast to UBOs, probable tumors were most frequently located within the globus pallidus and medulla, and rarely occurred prior to 3 years of age.

Conclusions

With the implementation of standardized radiologic criteria, a high prevalence of brain tumors was identified in this at-risk population of children, of which nearly one-third required treatment, emphasizing the need for appropriate oncologic surveillance for patients with NF1 harboring nonoptic pathway brain tumors.

The mTOR pathway in treatment of epilepsy: a clinical update

Nearly a third of patients with epilepsy have seizures refractory to current medical therapies. In the search for novel drug targets, the mTOR pathway has emerged as key in the regulation of neuronal function, growth and survival, and other cellular processes related to epileptogenesis. Hyperactivation of the mTOR pathway has been implicated in tuberous sclerosis complex and other 'mTORopathies', clinical syndromes associated with cortical developmental malformations and drug-resistant epilepsy. Recently published clinical trials of mTOR inhibitors in tuberous sclerosis complex have shown that these drugs are effective at decreasing seizure frequency. Future studies may establish whether mTOR inhibitors can provide effective treatment for patients with diverse genetic and acquired epilepsies, including preventative, disease-modifying therapies.

Histopathologic correlation with diffusion tensor imaging after chronic hypoxia in the immature ferret

INTRODUCTION

Chronic hypoxia in rodents induces white matter (WM) injury similar to that in human preterm infants. We used diffusion tensor imaging (DTI) and immunohistochemistry to study the impact of hypoxia in the immature ferret at two developmental time points relevant to the preterm and term brain.

RESULTS

On ex vivo imaging, the apparent diffusion coefficient (ADC) was decreased throughout the WM after 10 days of hypoxia (hypoxia from postnatal day 10 (P10) to P20 and killed at P20 (early hypoxia P20)), corresponding to increased astrocytosis and decreased myelination. Diffusion values normalized after 10 days of normoxia (hypoxia from P10 to P20 and killed at P30 (early hypoxia P30)), but immunohistochemistry revealed significant astrocytosis and hypomyelination. In contrast, ADC and anisotropy were increased after 10 days of hypoxia at a later developmental time point (hypoxia from P20 to P30 and killed at P30 (late hypoxia P30)), with less astrocytosis and more prominent myelination.

DISCUSSION

The patterns of alteration in imaging and histology varied in relation to the developmental time at which hypoxia occurred. Normalization of diffusion measures did not correspond to the normalization of underlying histopathology.

METHODS

Ferrets were subjected to 10% hypoxia and divided into three groups: early hypoxia P20, early hypoxia P30, and late hypoxia P30.

Do admissions and discharges to long-term care facilities influence hospital burden of Clostridium difficile infection?

BACKGROUND

Substantial geographical clustering of Clostridium difficile infection (CDI) outbreaks in hospitals in the USA have previously been demonstrated.

AIM

To test the hypothesis that hospital burden of CDI is associated with admission from and discharge to long-term care facilities (LTCFs).

METHODS

Hospital discharge data from 19 states in the USA were used to identify all patients discharged with a diagnosis of CDI from 1 January 2002 to 31 December 2004. For every hospital, the proportion of discharges with a diagnosis of CDI was calculated, and those above the 90th percentile were classified as 'high CDI' hospitals. We tested the association between this measure of hospital burden of CDI and the rates of admission from and discharges to LTCFs. We adjusted for other hospital level characteristics, case-complexity and local population characteristics.

FINDINGS

We identified 38,372,951 discharges during the three-year study period. Of all discharges, 274,311 (0.71%) had a primary or secondary diagnosis of CDI. Hospitals had a mean CDI burden of 7.8 cases per 1000 discharges. High CDI hospitals (N = 610; 10.0%) had a mean CDI burden of 34.8 cases per 1000 discharges. Compared to other hospitals, high CDI hospitals were more likely to have a high proportion of admissions from or discharges to LTCFs. This association persisted after adjustments for other hospital characteristics, case-complexity, and area population characteristics.

CONCLUSION

A high rate of admission from or discharge to LTCFs is associated with an increased hospital burden of CDI.

Development of predictive models for airflow obstruction in alpha-1-antitrypsin deficiency

Alpha-1-antitrypsin deficiency is a genetic condition associated with severe, early-onset chronic obstructive pulmonary disease (COPD). However, there is significant variability in lung function impairment among persons with the protease inhibitor ZZ genotype. Early identification of persons at highest risk of developing lung disease could be beneficial in guiding monitoring and treatment decisions. Using a multicenter, family-based study sample (2002-2005) of 372 persons with the protease inhibitor ZZ genotype, the authors developed prediction models for forced expiratory volume in 1 second (FEV(1)) and the presence of severe COPD using demographic, clinical, and genetic variables. Half of the data sample was used for model development, and the other half was used for model validation. In the training sample, variables found to be predictive of both FEV(1) and severe COPD were age, sex, pack-years of smoking, bronchodilator responsiveness, chronic bronchitis symptoms, and index case status. In the validation sample, the predictive model for FEV(1) explained 50% of the variance in FEV(1), and the model for severe COPD exhibited excellent discrimination (c statistic = 0.88).

Characterization of brain development in the ferret via MRI

Animal models with complex cortical development are useful for improving our understanding of the wide spectrum of neurodevelopmental challenges facing human preterm infants. MRI techniques can define both cerebral injury and alterations in cerebral development with translation between animal models and the human infant. We hypothesized that the immature ferret would display a similar sequence of brain development [both gray (GM) and white matter (WM)] to that of the preterm human infant. We describe postnatal ferret neurodevelopment with conventional and diffusion MRI. The ferret is born lissencephalic with a thin cortical plate and relatively large ventricles. Cortical folding and WM maturation take place during the first month of life. From the mid-second through the third week of postnatal life, the ferret brain undergoes a similar, though less complex, pattern of maturational changes to those observed in the human brain during the second half of gestation. GM anisotropy decreases rapidly in the first 3 wks of life, followed by an upward surge of surface folding and WM anisotropy over the next 2 wks.

Inflammation and cardiovascular events in individuals with and without chronic kidney disease

Inflammation and chronic kidney disease predict cardiovascular events. Here we evaluated markers of inflammation including fibrinogen, albumin and white blood cell count in individuals with and without stages 3-4 chronic kidney disease to assess inflammation as a risk factor for adverse events, the synergy between inflammation and chronic kidney disease, and the prognostic ability of these inflammatory markers relative to that of C-reactive protein. Using Atherosclerosis Risk in Communities and Cardiovascular Health Study data, inflammation was defined by worst quartile of at least 2 of these 3 markers. In Cox regression models, inflammation was assessed as a risk factor for a composite of cardiac events, stroke and mortality as well as components of this composite. Among 20 413 patients, inflammation was identified in 3594 and chronic kidney disease in 1649. In multivariable analyses, both inflammation and chronic kidney disease predicted all outcomes, but their interaction was non-significant. In 5597 patients with C-reactive protein levels, inflammation and elevated C-reactive protein had similar hazard ratios. When focusing only on individuals with the worst quartile of white cell count and albumin, results remained consistent.

Serious injuries and deaths of adolescent girls resulting from interpersonal violence: characteristics and trends from the United States, 1989-1998

BACKGROUND

Little published data are available concerning the death and disability of adolescent girls resulting from interpersonal violence (adolescents are defined as those aged 12-18 years in this study).

OBJECTIVES

To determine whether there were sex differences in (a) the characteristics of those who were injured or died, (b) injury severity and outcomes, and (c) injury mechanism; and to describe time trends in these differences.

DESIGN

Analysis of data concerning serious injuries due to assaults, recorded in the National Pediatric Trauma Registry (from January 1, 1989, through December 31, 1998), and homicides, recorded in the Web-Based Injury Statistics and Query Reporting System database (from January 1, 1990, through December 31, 1997).

SETTING

Patient data from participating pediatric trauma centers (National Pediatric Trauma Registry) in 45 states and national death certificate data (Web-Based Injury Statistics and Query Reporting System).

PATIENTS

Six hundred twelve adolescent girls who were seriously injured because of an assault were compared with 2656 adolescent boys who were seriously injured because of an assault. Three thousand four hundred eighty-seven adolescent girls who died due to a homicide were compared with 17 292 adolescent boys who died due to a homicide.

RESULTS

Assaulted adolescent girls were more likely to have preexisting cognitive or psychosocial impairments than were adolescent boys (odds ratio, 1.68; 95% confidence interval, 1.12-2.51). Adolescent girls trended toward more injury-related impairments at discharge from the hospital (odds ratio, 1.16; 95% confidence interval, 0.92-1.47). Adolescent girls were more likely to have been stabbed, and less likely to have been shot. Also, adolescent girls were more likely to have been injured at a home or a residence. Compared with all National Pediatric Trauma Registry admissions, assaults declined at the same rate for adolescent girls and boys. The proportion resulting from penetrating trauma declined more slowly for adolescent girls.

CONCLUSIONS

Interpersonal violence causes considerable morbidity and mortality for young women. Research and interventions should be developed to respond to adolescent girls who experience interpersonal violence.

End-of-life care in the pediatric intensive care unit: Attitudes and practices of pediatric critical care physicians and nurses

OBJECTIVE

To determine the attitudes and practices of pediatric critical care attending physicians and pediatric critical care nurses on end-of-life care.

DESIGN

Cross-sectional survey.

SETTING

A random sample of clinicians at 31 pediatric hospitals in the United States.

MEASUREMENTS AND MAIN RESULTS

The survey was completed by 110/130 (85%) physicians and 92/130 (71%) nurses. The statement that withholding and withdrawing life support is unethical was not endorsed by any of the physicians or nurses. More physicians (78%) than nurses (57%) agreed or strongly agreed that withholding and withdrawing are ethically the same (p < .001). Physicians were more likely than nurses to report that families are well informed about the advantages and limitations of further therapy (99% vs. 89%; p < .003); that ethical issues are discussed well within the team (92% vs. 59%; p < .0003), and that ethical issues are discussed well with the family (91% vs. 79%; p < .0002). On multivariable analyses, fewer years of practice in pediatric critical care was the only clinician characteristic associated with attitudes on end-of-life care dissimilar to the consensus positions reached by national medical and nursing organizations on these issues. There was no association between clinician characteristics such as their political or religious affiliation, practice-related variables such as the size of their intensive care unit or the presence of residents and fellows, and particular attitudes about end-of-life care.

CONCLUSIONS

Nearly two-thirds of pediatric critical care physicians and nurses express views on end-of-life care in strong agreement with consensus positions on these issues adopted by national professional organizations. Clinicians with fewer years of pediatric critical care practice are less likely to agree with this consensus. Compared with physicians, nurses are significantly less likely to agree that families are well informed and ethical issues are well discussed when assessing actual practice in their intensive care unit. More collaborative education and regular case review on bioethical issues are needed as part of standard practice in the intensive care unit.

Acute cardiac ischemia in patients with cocaine-associated complaints: results of a multicenter trial

STUDY OBJECTIVE

To describe the characteristics of a large group of patients who presented to emergency departments with cocaine-associated symptoms consistent with acute cardiac ischemia (ACI) and to determine the incidence of confirmed ACI including acute myocardial infarction (AMI) in this population.

METHODS

We performed a substudy on all patients in a multicenter prospective clinical trial (the Acute Cardiac Ischemia-Time Insensitive Predictive Instrument [ACI-TIPI] Clinical Trial) that enrolled ED patients with chest pain or other symptoms consistent with ACI including subjects with identified cocaine use. Demographic and clinical features, including initial and follow-up clinical data, ECGs, and tests to determine serum creatine kinase isoenzyme MB subunit concentrations, were analyzed. Diagnoses of AMI followed the World Health Organization criteria for AMI and of angina pectoris, the Canadian Cardiovascular Society Classification.

RESULTS

Of the 10,689 patients enrolled in the trial, 293 (2.7%) had cocaine-associated complaints. Among the 10 participating hospitals, the incidence of patients with cocaine-associated symptoms varied from 0.3% to 8.4%. Only 6 patients (2.0%, 95% confidence interval [CI] 0.76% to 4.4%) had a diagnosis of ACI; 4 (1.4%, 95% CI 0.37% to 3.5%) had unstable angina, and 2 (0.7%, 95% CI 0.08% to 2.4%) had AMI. Although patients with cocaine-induced complaints were as likely to be admitted to the coronary care unit compared with all study patients without cocaine use (14% versus 18%, P =.14, difference not significant), these patients were much less likely to have confirmed unstable angina (1.4% versus 9.3%, P <.001) or AMI (0. 7% versus 8.6%, P <.001). Compared with patients younger than 45 years, patients with cocaine usage were more likely to be admitted to the ICU (14% versus 8.0%, P =.0018) but less likely to have confirmed AMI (0.7% versus 2.8%, P =.033).

CONCLUSION

Patients presenting to EDs with cocaine-associated chest pain or related symptoms infrequently had ACI, and even less so, AMI. This suggests the need for selectivity in the hospitalization of patients with such cocaine-associated symptoms.

End-of-life care in the pediatric intensive care unit after the forgoing of life-sustaining treatment

OBJECTIVE

To describe the attitudes and practice of clinicians in providing sedation and analgesia to dying patients as life-sustaining treatment is withdrawn.

STUDY DESIGN

Prospective case series of 53 consecutive patients who died after the withdrawal of life-sustaining treatment in the pediatric intensive care unit at three teaching hospitals in Boston. Data on the reasons why medications were given were obtained from a self-administered anonymous questionnaire completed by the critical care physician and nurse for each case. Data on what medications were given were obtained from a review of the medical record.

RESULTS

Sedatives and/or analgesics were administered to 47 (89%) patients who died after the withdrawal of life-sustaining treatment. Patients who were comatose were less likely to receive these medications. Physicians and nurses cited treatment of pain, anxiety, and air hunger as the most common reasons, and hastening death as the least common reason, for administration of these medications. Hastening death was viewed as an "acceptable, unintended side effect" of terminal care by 91% of physician-nurse matched pairs. The mean dose of sedatives and analgesics administered nearly doubled as life-support was withdrawn, and the degree of escalation in dose did not correlate with clinician's views on hastening death.

CONCLUSION

Clinicians frequently escalate the dose of sedatives or analgesics to dying patients as life-sustaining treatment is withdrawn, citing patient-centered reasons as their principle justification. Hastening death is seen as an unintended consequence of appropriate care. A large majority of physicians and nurses agreed with patient management and were satisfied with the care provided. Care of the dying patient after the forgoing of life-sustaining treatment remains underanalyzed and needs more rigorous examination by the critical care community.

Missed diagnoses of acute cardiac ischemia in the emergency department

BACKGROUND

Discharging patients with acute myocardial infarction or unstable angina from the emergency department because of missed diagnoses can have dire consequences. We studied the incidence of, factors related to, and clinical outcomes of failure to hospitalize patients with acute cardiac ischemia.

METHODS

We analyzed clinical data from a multicenter, prospective clinical trial of all patients with chest pain or other symptoms suggesting acute cardiac ischemia who presented to the emergency departments of 10 U.S. hospitals.

RESULTS

Of 10,689 patients, 17 percent ultimately met the criteria for acute cardiac ischemia (8 percent had acute myocardial infarction and 9 percent had unstable angina), 6 percent had stable angina, 21 percent had other cardiac problems, and 55 percent had noncardiac problems. Among the 889 patients with acute myocardial infarction, 19 (2.1 percent) were mistakenly discharged from the emergency department (95 percent confidence interval, 1.1 to 3.1 percent); among the 966 patients with unstable angina, 22 (2.3 percent) were mistakenly discharged (95 percent confidence interval, 1.3 to 3.2 percent). Multivariable analysis showed that patients who presented to the emergency department with acute cardiac ischemia were more likely not to be hospitalized if they were women less than 55 years old (odds ratio for discharge, 6.7; 95 percent confidence interval, 1.4 to 32.5), were nonwhite (odds ratio, 2.2; 1.1 to 4.3), reported shortness of breath as their chief symptom (odds ratio, 2.7; 1.1 to 6.5), or had a normal or nondiagnostic electrocardiogram (odds ratio, 3.3; 1.7 to 6.3). Patients with acute infarction were more likely not to be hospitalized if they were nonwhite (odds ratio for discharge, 4.5; 95 percent confidence interval, 1.8 to 11.8) or had a normal or nondiagnostic electrocardiogram (odds ratio, 7.7; 95 percent confidence interval, 2.9 to 20.2). For the patients with acute infarction, the risk-adjusted mortality ratio for those who were not hospitalized, as compared with those who were, was 1.9 (95 percent confidence interval, 0.7 to 5.2), and for the patients with unstable angina, it was 1.7 (95 percent confidence interval, 0.2 to 17.0).

CONCLUSIONS

The percentage of patients who present to the emergency department with acute myocardial infarction or unstable angina who are not hospitalized is low, but the discharge of such patients is associated with increased mortality. Failure to hospitalize is related to race, sex, and the absence of typical features of cardiac ischemia. Continued efforts to reduce the number of missed diagnoses are warranted.

A predictive model for the development of hepatocellular carcinoma, liver failure, or liver transplantation for patients presenting to clinic with chronic hepatitis C

OBJECTIVE

Chronic infection with hepatitis C may lead to the development of cirrhosis, liver failure, and hepatocellular carcinoma. However, not all patients progress to these endpoints. Ideally, clinicians could improve their capability of stratifying the risk and the time frame within which their patients will progress to these endpoints. The purpose of the present study was to construct statistical models predicting disease progression for individual patients.

METHODS

Study endpoints were the development of hepatocellular carcinoma, liver transplantation, or death due to liver disease. The study cohort was 256 patients with hepatitis C acquired from either blood transfusion or use of intravenous drugs. During follow-up, 17 patients developed hepatocellular carcinoma, seven received liver transplantation, and 12 died from liver disease.

RESULTS

On multivariate analysis a history of decompensation (relative risk [RR] 4.321, 95% confidence interval [CI] 1.777-10.511) and the serum albumin (RR 0.253, 95% CI 0.136-0.474) were independently associated with the study endpoints. Patients without a history of decompensation and with a serum albumin > or = 4.1 mg/dl had a 3.2% chance of developing the study endpoints within 5 yr. Patients with a history of decompensation and a serum albumin < 4.1 mg/dl had a 40% chance of developing a study endpoint within 5 yr. Baseline genotype and quantitative RNA were not associated with development of the clinical endpoints, with the exception of patients coinfected with two or more genotypes.

CONCLUSION

Thus, the serum albumin and a history of decompensation are useful for predicting the development of hepatocellular carcinoma, liver transplantation, and death due to liver disease among patients with hepatitis C.

Evaluation of coronary revascularization to prevent tachycardia recurrences in survivors of ventricular fibrillation

Long-term follow-up of 29 consecutive survivors of ventricular fibrillation who underwent revascularization demonstrated that recurrent arrhythmics events were common. Because revascularization alone does not prevent arrhythmia recurrence, treatment with an implantable defibrillator should be considered in these patients.

Use of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI) to assist with triage of patients with chest pain or other symptoms suggestive of acute cardiac ischemia. A multicenter, controlled clinical trial

BACKGROUND

Approximately 6 million U.S. patients present to emergency departments annually with symptoms suggesting acute cardiac ischemia. Triage decisions for these patients are important but remain difficult.

OBJECTIVE

To test whether computerized prediction of the probability of acute ischemia, used with electrocardiography, improves the accuracy of triage decisions.

DESIGN

Controlled clinical trial.

SETTING

10 hospital emergency departments in the midwestern, southeastern, and northeastern United States.

PATIENTS

10689 patients with chest pain or other symptoms suggestive of acute cardiac ischemia.

INTERVENTION

The probability of acute ischemia predicted by the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI), either automatically printed or not printed on patients' electrocardiograms.

MEASUREMENTS

Emergency department triage to a coronary care unit (CCU), telemetry unit, ward, or home. Other measurements were the bed capacity of the CCU relative to that of the telemetry unit; training or supervision status of the triaging physician; and patient diagnoses and outcomes based on clinical, electrocardiographic, and creatine kinase data.

RESULTS

For patients without cardiac ischemia, in hospitals with high-capacity CCUs and relatively low-capacity cardiac telemetry units, use of ACI-TIPI was associated with a reduction in CCU admissions from 15% to 12%, a change of -16% (95% CI, -30% to 0%), and an increase in emergency department discharges to home from 49% to 52%, a change of 6% (CI, 0% to 14%; overall P=0.09). Across all hospitals, for patients evaluated by unsupervised residents, use of ACI-TIPI was associated with a reduction in CCU admissions from 14% to 10%, a change of -32% (CI, -55% to 3%); a reduction in telemetry unit admissions from 39% to 31%, a change of -20% (CI, -34% to -2%); and an increase in discharges to home from 45% to 56%, a change of 25% (CI, 8% to 45%; overall P=0.008). Among patients with stable angina, in hospitals with high-capacity CCUs, use of ACI-TIPI was associated with a reduction in CCU admissions from 26% to 13%, a change of -50% (CI, -70% to -17%), and an increase in discharges to home from 20% to 22%, a change of 10% (CI, -29% to 71%; overall P=0.02). At hospitals with high-capacity telemetry units, use of ACI-TIPI was associated with a reduction in telemetry unit admissions from 68% to 59%, a change of -14% (CI, -27% to 1%), and an increase in emergency department discharges to home from 10% to 21%, a change of 100% (CI, 22% to 230%; overall P=0.02). Among patients with acute myocardial infarction or unstable angina, use of ACI-TIPI did not change appropriate admission (96%) to the CCU or telemetry unit at hospitals with high-capacity CCUs or telemetry units.

CONCLUSIONS

Use of ACI-TIPI was associated with reduced hospitalization among emergency department patients without acute cardiac ischemia. This result varied as expected according to the CCU and cardiac telemetry unit capacities and physician supervision at individual hospitals. Appropriate admission for unstable angina or acute infarction was not affected. If ACI-TIPI is used widely in the United States, its potential incremental impact may be more than 200000 fewer unnecessary hospitalizations and more than 100000 fewer unnecessary CCU admissions.

Insurance type and the transportation to emergency departments of patients with acute cardiac ischemia: the ACI-TIPI Trial Insurance Study

The relationship of insurance type to treatment-seeking behavior (ie, the transportation to emergency departments of patients with symptoms suggestive of acute cardiac ischemia) was evaluated. The focus was on comparing patients belonging to a health maintenance organization (HMO) with patients who had indemnity insurance. Data were collected prospectively on 10,783 patients presenting to emergency departments of 10 adult care hospitals in the Eastern and Midwestern United States between April and December 1993 as part of a clinical trial. A total of 6,604 patients presented within 24 hours of symptom onset. Although these patients as a group had a wide range of demographic and clinical characteristics, persons belonging to an HMO and those with indemnity insurance were very similar. The main outcome measures were whether the patient was transported by ambulance and the duration of time from symptom onset to emergency department arrival. A hospital-matched sample of HMO-insured and indemnity-insured patients allowed multivariable regression: HMO membership was not associated with a different rate of ambulance use (odds ratio = 1.0; 95% confidence interval = 0.73, 1.35) or duration of time from symptom onset to emergency department presentation (6 minutes less, P = 0.8). HMO participation was not related to treatment-seeking behavior, as reflected by ambulance use and duration of time from symptom onset to emergency department arrival. However, studies of more constrained managed care organizations and of broader ranges of patients are needed.

Pseudoseizures, families, and unspeakable dilemmas

Fourteen videotaped family interviews of patients with diagnosed pseudoseizures were studied to determine the relationship of the symptoms to unspeakable dilemmas as forced choices imposed by family or social circumstances under conditions that also require the ensuing distress to be hidden. An unspeakable dilemma was evident in 13 of 14 interviews, with the patient the most silent family member in 13 interviews. In six cases, there was revealed a realistic threat of physical or sexual assault to a person involved in the problem, although not always the patient. These findings point to an important role for family therapy skills in the evaluation and treatment of pseudoseizures.

A logistic regression model when some events precede treatment: the effect of thrombolytic therapy for acute myocardial infarction on the risk of cardiac arrest

When outcomes occur in clinical trials before treatment can be given, neither intent-to-treat nor according-to-protocol analyses give optimal estimates of the treatment effect. A better approach employs a time-dependent variable for treatment. Intent-to-treat analyses are conservative, biasing against treatment; according-to-protocol analyses bias in favor of treatment. We show how to measure the effect of a time-dependent variable in a logistic regression using person-time intervals as units of measurement and describe appropriate methods for reporting model performance. The method is applied to develop a model to predict the probability that a patient with a myocardial infarction will have a sudden cardiac arrest within 48 hours of presentation to emergency medical services both when treated with thrombolysis and when not treated. We use a time-dependent treatment variable because many patients went into cardiac arrest while awaiting treatment. This technique has been programmed into an electrocardiograph for real-time use in an emergency department.

Patient-specific predictions of outcomes in myocardial infarction for real-time emergency use: a thrombolytic predictive instrument

BACKGROUND

Thrombolytic therapy can be life-saving in patients with acute myocardial infarction. However, if given too late or insufficiently selectively, it may provide little benefit but still cause serious complications and incur substantial costs.

OBJECTIVE

To develop a thrombolytic predictive instrument for real-time use in emergency medical service settings that could 1) identify patients likely to benefit from thrombolysis and 2) facilitate the earliest possible use of this therapy.

DESIGN

Creation and validation of logistic regression-based predictive instruments based on secondary analysis of clinical data.

PATIENTS

4911 patients who had acute myocardial infarction and ST-segment elevation on electrocardiogram; 3483 received thrombolytic therapy.

MEASUREMENTS

Data were obtained from 13 major clinical trials and registries and directly from medical records, including electrocardiograms obtained at presentation. Input variables include presenting clinical and electrocardiography features; predictive models generate probabilities for acute (30-day) mortality if and if not treated with thrombolysis, 1-year mortality rates if and if not treated with thrombolysis, cardiac arrest if and if not treated with thrombolysis, thrombolysis-related intracranial hemorrhage, and thrombolysis-related major bleeding episode requiring transfusion. Together, these models constitute the thrombolytic predictive instrument.

RESULTS

The predictive models generated the following mean predictions for patients in the Thrombolytic Predictive instrument Database: 30-day mortality rate, 7.1%; 1-year mortality rate, 10.9%; rate of cardiac arrest, 3.7%; rate of thrombolysis-related intracranial hemorrhage. 0.6%; and rate of other thrombolysis-related major bleeding episodes, 5.0%. They discriminated with between persons having and those not having the predicted outcome; areas under the receiver-operating characteristic (ROC) curve were between 0.77 and 0.84 for the five outcomes. Calibration between each instrument's predicted and observed served rates was excellent. Validation of the predictive instruments of 30-day and 1-year mortality, done on a separate test dataset, yielded areas under the ROC curve of 0.76 for each

CONCLUSIONS

After the basic features of a clinical presentation are entered into a computerized electrocardiograph, the predictions of the thrombolytic predictive instrument can be printed on the electrocardiogram report. This decision aid may facilitate earlier and more appropriate use of thrombolytic therapy in patients with acute myocardial infarction.

Causes of chest pain and symptoms suggestive of acute cardiac ischemia in African-American patients presenting to the emergency department: a multicenter study

This study examines whether race is a significant determinant of the diagnoses of acute myocardial infarction or angina pectoris in patients with symptoms suggestive of acute cardiac ischemia. The study population was comprised of 3401 (34%) African-American and 6600 (66%) white patients who presented to emergency departments with symptoms suggestive of acute cardiac ischemia. The main outcome measure was a diagnosis of acute myocardial infarction or angina pectoris. African Americans were younger, predominantly female, and more often had hypertension, diabetes mellitus, or smoked. The diagnosis of acute myocardial infarction was confirmed in 6% of African-American and 12% of white men, and in 4% of African-American and 8% of white women. After adjusting for age, gender, medical history, signs and symptoms, and hospital, African Americans were half as likely to develop acute myocardial infarction and were 60% as likely to have acute cardiac ischemia. Despite having less acute cardiac ischemia, African Americans in this study had high risk levels for coronary artery disease.

Cytomegalovirus disease is associated with increased cost and hospital length of stay among orthotopic liver transplant recipients

Cytomegalovirus (CMV) is a cause of considerable morbidity and mortality among orthotopic liver transplant (OLT) recipients. To study the impact of CMV on cost and hospital length of stay in this population, we undertook an analysis of a cohort of OLT recipients from four transplant centers in Boston who participated in a CMV prophylaxis trial. First posttransplant year hospital length of stay (including the hospital stay after transplantation and readmissions within 1 year after transplantation) was available for all 141 patients included in the study. In a multiple linear regression model bacteremia (P=0.0001), CMV disease (P=0.0007), abdominal reexploration (excluding retransplantation) (P=0.0070), recipient age < or = 16 years (P=0.0352), and the number of units of blood products (red blood cells, platelets, or fresh frozen plasma) administered during transplantation (P=0.0523) were shown to be independently associated with longer first posttransplant year hospital length of stay. Cost data for in-hospital care for the year beginning with admission for liver transplantation were available for 66 OLT recipients. Using a multiple linear regression model, development of CMV disease (P=0.0001), the number of units of blood products administered during transplantation (P=0.0001), bacteremia (P=0.0002), decreased pretransplant renal function (estimated by creatinine clearance) (P=0.0109), and need for retransplantation (P=0.0619) were shown to be independently associated with higher cost. These data strongly suggest that CMV disease has a direct impact on cost and hospital length of stay in liver transplantation.

Hospital mortality in women and men with acute cardiac ischemia: a prospective multicenter study

OBJECTIVES

This study sought to determine gender differences in hospital mortality in patients with acute cardiac ischemia.

BACKGROUND

It is unclear why women experience higher mortality from acute myocardial infarction (AMI) than men and whether this applies to all patients with acute ischemia.

METHODS

We analyzed data from a prospective multicenter study involving patients presenting to the emergency department (ED) with symptoms suggestive of acute ischemia.

RESULTS

Of 10,783 patients, 5,221 (48.4%) were women. Mean age was 60.5 years for women and 56.9 for men (p < 0.001). Women had more hypertension (54.6% vs. 45.9%, p < 0.001) and diabetes (23.3% vs. 17.0%, p < 0.001) than men but fewer previous AMIs (21.1% vs. 28.9%, p < 0.001). Acute ischemia was confirmed in 1,090 women (20.8%) and 1,451 men (26.1%, p < 0.001), including AMI in 322 women (6.2%) and 572 men (10.3%, p < 0.001). Women with an AMI were in a higher Killip class than men: class I in 60.3% versus 72.2%, class II in 19.3% versus 16%, class III in 15.5% versus 8.7% and class IV in 5% versus 3.1%, respectively (p = 0.001). There was no significant difference in mortality from acute ischemia between genders (4.0% vs. 3.5%, p = 0.6), but there was a trend for higher AMI mortality in women (10.3% vs. 7.4%, p = 0.1). After controlling for age, diabetes, heart failure and presenting blood pressure, gender did not predict mortality from acute ischemia (odds ratio 0.9, 95% confidence interval 0.5 to 1.4, p = 0.5).

CONCLUSIONS

Among patients presenting to the ED with acute cardiac ischemia, gender does not appear to be an independent predictor of hospital mortality. The trend for higher mortality in women from AMI can be explained by their older age, greater frequency of diabetes and higher Killip class on presentation.

Interference with cardiac pacemakers by cellular telephones

BACKGROUND

A growing body of evidence suggests that electromagnetic interference may occur between cardiac pacemakers and wireless hand-held (cellular) telephones, posing a potential public health problem. Electromagnetic interference may occur when the pacemaker is exposed to an electromagnetic field generated by the cellular telephone.

METHODS

In this multicenter, prospective, crossover study, we tested 980 patients with cardiac pacemakers with five types of telephones (one analogue and four digital) to assess the potential for interference. Telephones were tested in a test mode and were programmed to transmit at the maximal power, simulating the worst-case scenario; in addition, one telephone was tested during actual transmission to simulate actual use. Patients were electrocardiographically monitored while the telephones were tested at the ipsilateral ear and in a series of maneuvers directly over the pacemaker. Interference was classified according to the type and clinical significance of the effect.

RESULTS

The incidence of any type of interference was 20 percent in the 5533 tests, and the incidence of symptoms was 7.2 percent. The incidence of clinically significant interference was 6.6 percent. There was no clinically significant interference when the telephone was placed in the normal position over the ear. Interference that was definitely clinically significant occurred in only 1.7 percent of tests, and only when the telephone was held over the pacemaker. Interference was more frequent with dual-chamber pacemakers (25.3 percent) than with single-chamber pacemakers (6.8 percent, P<0.001) and more frequent with pacemakers without feed-through filters (28.9 to 55.8 percent) than with those with such filters (0.4 to 0.8 percent, P=0.01).

CONCLUSIONS

Cellular telephones can interfere with the function of implanted cardiac pacemakers. However, when telephones are placed over the ear, the normal position, this interference does not pose a health risk.

Redefining the role of family therapy in psychiatric residency education

In order to learn how psychiatry residents use family therapy training from residency in their clinical practices after graduation, the authors interviewed graduates from a large program in the metropolitan Northeast and a small program in the rural South. Graduates from both programs were using family therapy theory and skills to a greater extent than they had anticipated during residency. However, these skills were being used primarily to treat individual patients and to solve clinical and administrative problems in settings other than traditional couple and family therapies. Based on the findings, the authors suggest a restructuring of content and redefinition of role for family therapy training in psychiatry residencies.

High incidence of appropriate implantable cardioverter-defibrillator therapy in patients with syncope of unknown etiology and inducible ventricular arrhythmias

OBJECTIVES

This study evaluates the hypothesis that in patients with syncope of unknown origin, inducible ventricular arrhythmias are specific arrhythmias and therefore should be appropriately treated.

BACKGROUND

Although syncope is a common clinical entity, the evaluation and treatment of patients with syncope without a clear etiology are not well defined. Many patients with syncope of undetermined origin undergo invasive electrophysiologic evaluation. Abnormalities of the sinus node, prolongation of conduction times or inducible arrhythmias found at these evaluations are usually assumed to be the cause of syncope and are therefore treated. However, whether tachyarrhythmias are truly the cause of syncope, and whether treatment of these tachyarrhythmias can prevent recurrent syncope and arrhythmic death, is unknown.

METHODS

This study included 50 consecutive patients with syncope of undetermined origin, ventricular tachyarrhythmias at electrophysiologic evaluation and treatment with an implantable cardioverter-defibrillator.

RESULTS

Ventricular stimulation led to sustained monomorphic ventricular tachycardia in 36 patients, nonsustained ventricular tachycardia in 5 and ventricular fibrillation in 9. Over a 23 +/- 15-month (mean +/- SD) follow-up period, 18 patients received appropriate implantable cardioverter-defibrillator shock. Actuarial probability of appropriate therapy was 22% at 1 year and 50% at 3 years. Recurrent syncope was seen in five patients, three of whom had appropriate defibrillatory detections at the time of syncope. Four patients died (sudden death in one, congestive heart failure in two).

CONCLUSIONS

In patients with syncope of undetermined origin and inducible ventricular tachyarrhythmias, appropriate implantable cardioverter-defibrillator therapy is common at follow-up. Sudden cardiac death is uncommon. This low incidence of sudden cardiac death and high incidence of appropriate defibrillator therapy support the current practice of using implantable cardioverter-defibrillators in patients with syncope of unknown origin and inducible ventricular arrhythmias.

Presentations of acute myocardial infarction in men and women

OBJECTIVE

To assess the influence of gender on the likelihood of acute myocardial infarction (AMI) among emergency department (ED) patients with symptoms suggestive of acute cardiac ischemia, and to determine whether any specific presenting signs or symptoms are associated more strongly with AMI in women than in men.

DESIGN

Analysis of cohort data from a prospective clinical trial.

SETTING

Emergency departments of 10 hospitals of varying sizes and types in the United States.

PATIENTS

Patients 30 years of age or older (n = 10,525) who presented to the ED with chest pain or other symptoms suggestive of acute cardiac ischemia.

MEASUREMENTS AND MAIN RESULTS

The prevalence of AMI was determined for men and women, and a multivariable logistic regression model predicting AMI was developed to adjust for patients' demographic and clinical characteristics. AMI was almost twice as common in men as in women (10% vs 6%). Controlling for demographics, presenting signs and symptoms, electrocardiogram features, and hospital, male gender was a significant predictor of AMI (odds ratio [OR] 1.7; 95% confidence interval [CI] 1.4, 2.0). The gender effect was eliminated, however, among patients with ST-segment elevations on electrocardiogram (OR 1.1; 95% CI 0.7, 1.7) and among patients with signs of congestive heart failure (CHF) (OR 1.1; 95% CI 0.8, 1.5). Signs of CHF were associated with AMI among women (OR 1.9; 95% CI 1.4, 2.6) but not men (OR 1.0; 95% CI 0.8, 1.3). Among patients who presented to EDs with chest pain or other symptoms suggestive of acute cardiac ischemia, AMI was more likely in men than in women. Among women with ST-segment elevation or signs of CHF, however, AMI likelihood was similar to that in men with these characteristics.

The use of empiric clinical data in the evaluation of practice guidelines for unstable angina

OBJECTIVE

To determine the applicability to emergency department (ED) clinical practice of a nationally disseminated practice guideline on the disposition of patients with a diagnosis of unstable angina, and to determine the potential impact of the guideline on hospital admissions and demand for intensive care beds.

DESIGN

Application of guideline criteria for ED disposition decisions to a validation sample derived from a prospective clinical trial.

SETTING

Five hospitals, including 2 urban general teaching hospitals, 2 urban tertiary care university hospitals, and 1 suburban university-affiliated community hospital.

PATIENTS

A consecutive sample of 457 patients who presented with symptoms suggestive of acute cardiac ischemia and who had "unstable angina" or "rule out unstable angina" diagnosed by ED physicians. Greater than 90% of eligible patients were enrolled in the clinical trial; follow-up data sufficient for assignment of a definitive diagnosis were obtained for 99% of subjects.

MAIN OUTCOME MEASURES

Acute myocardial infarction and unstable angina, based on blind review of initial and follow-up clinical data, including cardiac enzyme levels and electrocardiograms. After completion of the trial, without knowledge of final diagnosis or outcome, the investigators classified patients into risk groups specified by the unstable angina guideline.

RESULTS

Of subjects with an ED diagnosis of unstable angina, only 6% (n=28) met the guideline's criteria corresponding to low risk for adverse events and were therefore suitable for discharge directly to home. Fifty-four percent (n=247) met the intermediate-risk criteria; 40% (n=182) met the high-risk criteria and were identified as requiring admission to an intensive care unit. Actual ED disposition differed from guideline recommendations in 2 major areas: only 4% (1/28) of low-risk patients were discharged to home with outpatient follow-up, and only 40% (72/182) of high-risk patients were admitted to an intensive care unit.

CONCLUSIONS

Although the guideline was intended to reduce hospitalization by identifying a low-risk group, the small size of this group among ED patients suggests that little reduction in hospitalization can be expected. Indeed, the guideline may increase demand for the limited number of intensive care beds to accommodate patients with unstable angina considered high-risk but currently placed elsewhere. These results emphasize the need to use empiric data from target clinical settings to assess the likely actual impact of guidelines on clinical care prior to national dissemination.

Influence of sex on the use of cardiac procedures in patients presenting to the emergency department. A prospective multicenter study

BACKGROUND

Reports about the use of cardiac procedures have produced conflicting results as to whether there is a sex bias in the use of thrombolytic therapy, cardiac catheterization, or revascularization procedures. The present study was undertaken with the hope of resolving some of these different findings by examining the use of these therapies in women and men who presented to the emergency department with symptoms suggestive of acute cardiac ischemia.

METHODS AND RESULTS

During 7 consecutive months in 1993, 10673 individuals > or = 30 years old who presented with chest pain or other symptoms suggestive of acute cardiac ischemia were enrolled in the Acute Cardiac Ischemia Time-Insensitive Predictive Instrument Clinical Trial at 10 hospitals in the East and Midwest. This study included 2542 patients (24% of all patients) who had confirmed acute myocardial infarction or angina pectoris. There were significant sex differences with respect to demographic and clinical characteristics and the use of cardiac procedures. Among patients with acute myocardial infarction, the use of thrombolytic therapy, cardiac catheterization, and revascularization procedures was similar in women and men after multivariate adjustment. However, in the group with angina pectoris, women were considerably less likely to undergo these procedures, even after adjustment for significant baseline covariates.

CONCLUSIONS

Women with angina pectoris were less likely to undergo cardiac catheterization or revascularization procedures, although unmeasured factors could in part explain the observed differences.

Prediction of the infarct-related artery in acute myocardial infarction by a scoring system using summary ST-segment and T-wave changes

We developed a scoring system to predict the artery responsible for an acute myocardial infarction (AMI) using ST-segment and T-wave changes on the initial electrocardiogram (ECG) using data from 228 patients (development set) with symptoms compatible with AMI and tested in a similar group of 223 patients (test set) from the Thrombolysis and Angioplasty in Myocardial Infarction (TAMI-5) Trial. Using stepwise logistic regression we were able to accurately predict the left anterior descending (LAD), right, or left circumflex (LC) coronary artery as the infarct-related artery using 2 variables: (1) the summation of the ST-segment elevation in leads V1 to V4; and (2) the summation of the T-wave negativity in leads I, aVL, and V5. In the development set, these 2 variables demonstrated respective sensitivity and specificity of 98% and 90% for LAD lesions, 82% and 85% for right narrowings, and 82% and 84% for LC narrowings. In the test set, the sensitivity and specificity were 97% and 95% for LAD lesions, 85% and 86% for right lesions, and 73% and 60% for LC coronary artery lesions. Information easily obtained on the ECG can accurately predict the likelihood of the LAD, right, or LC artery as the infarct-related artery. This may be useful in the decision to administer thrombolytic treatment.

A comparison of performance of mathematical predictive methods for medical diagnosis: identifying acute cardiac ischemia among emergency department patients

BACKGROUND

There is increasing interest in mathematical methods for the prediction of medical outcomes. Three methods have attracted particular attention: logistic regression, classification trees (such as ID3 and CART), and neural networks. To compare their relative performance, we used a large clinical database to develop and compare models using these methods.

METHODS

Each modeling method was used to generate predictive instruments for acute cardiac ischemia (which includes acute myocardial infarction and unstable angina pectoris), using prospectivel-collected clinical data on 5773 patients, who presented over a two year period to six hospitals' emergency departments with chest pain or symptoms suggesting acute ischemia. This data set was then split into training (n = 3453) and test (n = 2320) sets. Of 200 available variables, modeling was restricted to those available within the first 10 minutes of emergency department care (history, physical exam, and electrocardiogram).

RESULTS

When the number of variables was limited to eight, representing a practical number for input in the real-time clinical setting, the logistic regression's receiver-operating characteristic (ROC) curve area, as a measure of diagnostic performance, was 0.887; the classification tree model's ROC curve area was 0.858, and the neural network's ROC curve area was 0.902. When the number of variables used by a model was not limited, the logistic regression's ROC area was 0.905, the classification tree model's 0.861, and the neural network's 0.923. Among these models the neural networks had noticeably poorer calibration. When the outputs from each of these unrestricted models were presented to each of the other methods as an additional independent variable, the ROC areas of the new "hybrid" models were not significantly better than the original unlimited models (ROC areas 0.858 to 0.920).

CONCLUSIONS

Logistic regression, classification tree, and neural network models all can provide excellent predictive performance of medical outcomes for clinical decision aids and policy models. Their ultimate limitations seem due to the availability of the information in data (a "data barrier") rather than their respective intrinsic properties. Choices between these methods would seem to be most appropriately based on the needs of the specific application, rather than on the premise that any one of these methods is intrinsically more powerful.

The exclusion of women from clinical trials of thrombolytic therapy: implications for developing the thrombolytic predictive instrument database

The thrombolytic predictive instrument (TPI) was developed to identify those patients most likely to benefit from thrombolytic therapy for acute myocardial infarction as well as to facilitate the earliest possible administration of this treatment. The TPI consists of predictive models derived from clinical data obtained from both clinical trials and data registries. These models are subject to potential bias due to combinations of primary data from different sources. The purpose of this investigation was to assess the influence of gender in developing the TPI database. In this database, there were 1,096 (22%) women and 3,826 (78%) men; only 38% of the women were enrolled in clinical trials, whereas 46% of the men were (p < 0.0001). Within clinical trials, there were few significant eligibility differences between women and men, as the vast majority of patients met eligibility standards for entry in these trials. However, within clinical registries, the women were older (p < 0.0001) and more often had elevated blood pressure on admission (p = 0.002). Multivariate logistic regression indicated that after adjustment for significant predictors of trial inclusion, women were 25% less likely to be included in clinical trials (odds ratio = 0.76, 95% confidence interval = 0.60, 0.96). In order to counter bias introduced by the exclusion of women from clinical trials, the TPI database included patients from non-trial settings. Carefully including patients from clinical registries or non-trial settings may be an important strategy in constructing generally applicable predictive instruments.

Electrocardiographic left ventricular hypertrophy in patients with suspected acute cardiac ischemia--its influence on diagnosis, triage, and short-term prognosis: a multicenter study

OBJECTIVE

To understand the diagnostic and short-term prognostic significance of electrocardiographic left ventricular hypertrophy (ECG-LVH) for patients who present to the emergency department with symptoms suggesting acute cardiac ischemia, defined as new or unstable angina pectoris or acute myocardial infarction.

DESIGN

Subgroup analysis of a multicenter, prospective study of coronary care unit admitting practices in the prethrombolytic era.

SETTING

The emergency departments of six New England hospitals: two urban medical school teaching hospitals, two medical school-affiliated community hospitals in smaller cities, and two rural non-teaching teaching hospitals.

PATIENTS

5,768 patients presenting with symptoms suggesting possible acute cardiac ischemia, including 413 patients who had ECG-LVH defined by the Romhilt-Estes point score criteria and 5,355 patients who had other electrocardiogram (ECG) findings.

MAIN RESULTS

Only 26% of the 413 patients who had ECG-LVH were ultimately judged to have had acute cardiac ischemia, compared with 72% of patients who had primary ST-segment and T-wave abnormalities (p < 0.001) and 36% of those who had other ECG abnormalities (p < 0.001). Overall, the ECG-LVH patients were one-third less likely than the patients who did not have ECG-LVH to have had acute cardiac ischemia, after controlling for other predictors of acute ischemia by logistic regression (relative risk = 0.66, 95% CI 0.46 to 0.94). The patients who had ECG-LVH were only one-fourth as likely to have had acute myocardial infarctions as were the patients presenting with primary ST-segment and T-wave changes (12% vs 48%, p < 0.001). Instead, a much larger proportion had had congestive heart failure or hypertension. The admitting physicians had identified ECG-LVH poorly on the admitting ECGs: only 22% of those who had ECG-LVH had been correctly identified, and for more than 70%, the secondary ST-segment and T-wave changes of ECG-LVH had been read as being primary. The short-term mortality for the patients who had ECG-LVH was 7.5%. This was intermediate between the mortality for patients who had primary ST-segment and T-wave abnormalities (10.6%) and those who had other ECG abnormalities (5.1%). Mortality was not affected by whether the admitting physician had recognized ECG-LVH initially.

CONCLUSION

ECG-LVH was not a benign ECG finding among the patients who had presented with symptoms suggesting an acute cardiac ischemic syndrome: short-term mortality among the patients who had ECG-LVH (7.5%) approached that for the patients who had primary ST-segment and T-wave abnormalities (10.6%, p = 0.10). However, the patients who had ECG-LVH were one-third less likely to have had any acute cardiac ischemia than were the patients who did not have ECG-LVH, after logistic regression was used to control for other predictors of acute ischemia. Specifically, acute myocardial infarction was only one-fourth as likely when LVH was present on the admitting ECG (12%) as it was when primary ST-segment and T-wave abnormalities were present (48%, p < 0.001). Instead, congestive heart failure and hypertensive heart disease were more common. Thus, routine use of thrombolytic therapy for patients who have ECG-LVH does not seem warranted. ECG-LVH was poorly recognized (in only 22% of cases) by the physicians in the present study. Better recognition of this common ECG finding may lead to more effective patient management.

Presenting pulse pressure predicts thrombolytic therapy-related intracranial hemorrhage. Thrombolytic Predictive Instrument (TPI) Project results

BACKGROUND

In selecting patients with acute myocardial infarction for thrombolytic therapy, it is important to identify patients who are at high risk for intracranial hemorrhage, for whom thrombolytic therapy is ill advised. We hypothesized that presenting pulse blood pressure, representing the "hammer" effect on cerebral vessels and the effects of age on arterial compliance, might predict thrombolysis-related intracranial hemorrhage better than systolic, diastolic, or mean arterial blood pressures.

METHODS AND RESULTS

Of 3483 Thrombolytic Predictive Instrument (TPI) Project subjects receiving thrombolytic therapy for acute infarction, we identified and obtained detailed clinical data on the 19 with treatment-related intracranial hemorrhages confirmed by computed tomography and on 175 matched controls. Systolic, diastolic, mean arterial, and pulse blood pressures were each significantly related to the occurrence of intracranial hemorrhage, with pulse pressure most highly related. The mean pulse pressure in patients who developed intracranial hemorrhage was 63 mm Hg, 34% higher than the 47 mm Hg mean value for those not developing hemorrhage (P = .0001). Excess pulse pressure, defined as the extent to which a patient's pulse pressure exceeded 40 mm Hg for systolic blood pressures of at least 120 mm Hg, was even more strongly related: its mean value of 23 mm Hg for patients was 130% higher than its mean value of 10 mm Hg for controls (P < .0001). With logistic regression models to estimate the relative risks (odds ratios) for intracranial hemorrhage conferred by each form of blood pressure, the relative risk for hemorrhage was greatest for excess pulse pressure: for each 10-point pulse pressure excess, the relative risk for intracranial hemorrhage was increased by 1.85 (P = .0002; 95% confidence interval [CI], 1.34 to 2.55) by itself and 1.76 (P = .001; 95% CI, 1.26 to 2.46) when adjusted for age. In this sample, excess pulse pressure by itself predicted hemorrhage as well as systolic pressure and age together. When excess pulse pressure was combined with age to make a logistic regression model predicting intracranial hemorrhage, age contributed less to the prediction than when combined with the other blood pressure forms, even though this model predicted better than any other combination of age and pressure (receiver-operating characteristic curve area, 0.82 versus 0.77 with systolic pressure and age, 0.75 with mean arterial pressure, 0.71 with diastolic pressure, and 0.81 with both systolic and diastolic pressures).

CONCLUSIONS

We found that excess pulse blood pressure predicted thrombolysis-related intracranial hemorrhage better than other forms of pretreatment blood pressure, perhaps better describing the pathophysiology of intracranial hemorrhage, including the effect of age. These findings will need confirmation in larger studies with comparable clinical detail.

A time-insensitive predictive instrument for acute hospital mortality due to congestive heart failure: development, testing, and use for comparing hospitals: a multicenter study

The purpose of this study was to develop a "time-insensitive" predictive instrument (TIPI) for acute hospital mortality due to congestive heart failure. In Phase 1, based on prospectively collected data on 401 congestive heart failure patients among 5,773 study patients who presented to six New England hospitals over a 2-year period whose chief complaints were chest pain, shortness of breath, or other cardiac symptoms, a multivariable logistic regression was used to develop the TIPI for acute mortality. Discrimination between patients who lived and those who died was reflected by receiver-operating characteristic (ROC) curve area of 0.90. Predicted mortality was found to not vary significantly from actual mortality rates across deciles of predicted probabilities from 0% to 100%. In Phase 2, the six hospitals' actual mortality rates for their congestive heart failure patients were compared to their respective rates predicted by the TIPI. Actual hospital mortality rates ranged from 3.6% to 11.3%, with no hospital having a statistically significantly higher rate. Predicted mortality rates ranged from 4% to 9%, with one hospital having a significantly lower predicted rate (P = .01), and one hospital having a borderline significantly higher predicted rate (P = .07). Individual hospitals' differences between actual and predicted mortality ranged from -3.8% to +4.7% (all NS). When grouped by hospital type, respectively for urban teaching, smaller city teaching, and rural non-teaching hospitals, the actual mortality rates were 5.1%, 10.5%, and 5.4%, (NS). The predicted mortality rates were 8.3%, 6.1%, and 5.4%, respectively, with the rate for urban major teaching centers being significantly higher (P = .03). No hospital type had significant differences between their actual and predicted mortality rates (NS). This congestive heart failure mortality TIPI (CHFM-TIPI) shows potential for risk-adjusted studies of hospitals, mortality for multi-hospital groups, hospital-to-hospital comparisons, and potentially for within-hospital assessment and if further validated, potentially also for real-time clinical use.

Predicting recovery of severe regional ventricular dysfunction. Comparison of resting scintigraphy with 201Tl and 99mTc-sestamibi

BACKGROUND

Regional 201Tl activity after resting injection, imaged early and after redistribution, reflects viable myocardium and can predict improved isotope uptake as well as regional and global ventricular function after revascularization. 99mTc-sestamibi, a perfusion tracer with favorable imaging characteristics, has distinct kinetics compared with 201Tl, demonstrating minimal redistribution; this property may give 201Tl an advantage for detecting viable myocardium, particularly in segments with resting hypoperfusion. The purpose of this study was to compare regional activities of 201Tl and 99mTc-sestamibi after resting injections in patients with coronary artery disease and regional or global left ventricular dysfunction and to assess their comparative abilities for predicting recovery of severe regional ventricular dysfunction after revascularization.

METHODS AND RESULTS

Qualitative and quantitative comparisons of rest and redistribution 201Tl activity and sestamibi activity 1 hour after rest injection were performed in 31 patients with coronary artery disease and left ventricular dysfunction. Quantitative analysis of three short-axis tomograms per patient was performed by use of circumferential profiles that allowed analysis of 12 segments per patient. Two-dimensional echocardiography was used to assess wall motion and thickening in segments corresponding to the single photon emission computed tomography data. Concordance between regional 201Tl activity at redistribution imaging and regional sestamibi activity by semiquantitative visual analysis demonstrated concordant regional activity in 87% of segments; among discordant segments, no significant skew was seen, indicating enhanced uptake of one agent over the other. Quantitative analysis for all segments showed significant correlation (r = .86, P < .001) between quantitative regional 201Tl redistribution activity and 1-hour post-rest injection sestamibi activity in individual segments. Eighteen of these patients were revascularized, and echocardiography was repeated 20 +/- 16 days later; segments exhibiting significant regional ventricular dysfunction before revascularization were classified as having reversible or irreversible dysfunction on the basis of the change in wall motion and thickening. 201Tl and sestamibi regional activities were similar in those segments with reversible (72 +/- 11% [percent of peak activity] versus 75 +/- 9%, respectively, P = NS) as well as irreversible ventricular dysfunction (51 +/- 11% versus 50 +/- 8%, P = NS). Positive (75% versus 80% for 201Tl and sestamibi, respectively) and negative (92% versus 96%, respectively) predictive values for recovery of regional ventricular dysfunction after revascularization were similar for the two agents.

CONCLUSIONS

In patients with coronary artery disease and left ventricular dysfunction, quantified sestamibi activity 1 hour after rest injection parallels redistribution 201Tl activity after a resting injection, suggesting that uptake and subsequent handling of sestamibi are more complex than can be explained by a pure flow tracer with no redistribution. Quantitative analysis of regional activities of both 201Tl and sestamibi after resting injections can differentiate viable from nonviable myocardium, and the two agents comparably predict reversibility of significant regional wall motion abnormalities after revascularization in such patients to a similar degree.

Impact of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI) on the speed of triage decision making for emergency department patients presenting with chest pain: a controlled clinical trial

OBJECTIVE

Emergency department (ED) triage for acute cardiac ischemia in the primary teaching hospital in Geneva, Switzerland, is very accurate, but at the cost of very long ED stays. Thus, the authors sought: 1) to determine the impact of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI), incorporated into a computerized electrocardiograph, on length of stay and speed of triage decision making for ED patients presenting with symptoms suggesting acute cardiac ischemia, and 2) to study the ACI-TIPI's impact on physicians of different training levels.

DESIGN

A seven-month prospective clinical trial with alternating-month experimental and control periods.

SETTING

An urban major teaching hospital in Geneva, Switzerland.

PARTICIPANTS

Patients over the age of 18 years presenting to the ED with chest pain or other symptoms suggesting acute cardiac ischemia (acute myocardial infarction or unstable angina pectoris). Emergency department physicians, classified as novice (those in their first ED rotations) and experienced (those in their second or later ED rotations). Patients staying overnight in the ED (n = 111) were excluded from the analysis.

INTERVENTION

During the experimental months, the computerized electrocardiograph printed the ACI-TIPI probability of acute cardiac ischemia at the top of each subject's electrocardiogram. During control months, the probability was not provided.

MEASUREMENTS AND MAIN RESULTS

Among the 418 study subjects, for patients with acute ischemia seen by novice clinicians, the use of the ACI-TIPI decreased ED time from presentation to triage decision and ED release by 0.7 hour (19%) (p = 0.007). Subgroup analyses for patients with acute myocardial infarction, patients with unstable angina pectoris, and patients given thrombolytic therapy also showed analogous decreases in ED time consistent with this finding. Other key determinants of ED length of stay included: age, whether the coronary care unit was full, whether patients received thrombolytic therapy, and whether admission was during the night shift. The experimental and control groups did not differ in triage disposition appropriateness or mortality.

CONCLUSIONS

For ED patients with acute cardiac ischemia evaluated by novice clinicians, the ACI-TIPI substantially speeded ED decision making and triage. The suggestion of an impact on different cardiac ischemia subgroups and mortality deserves further larger clinical trials.

A comparison of logistic regression to decision-tree induction in a medical domain

This paper compares the performance of logistic regression to decision-tree induction in classifying patients as having acute cardiac ischemia. This comparison was performed using the database of 5773 patients originally used to develop the logistic-regression tool and test it prospectively. Both the ability to classify cases and the ability to estimate the probability of ischemia were compared on the default tree generated by the C4 version of ID3. They were also compared on a tree optimized on the learning set by increased pruning of overspecified branches, and on a tree incorporating clinical considerations. Both the LR tool and the improved trees performed at a level fairly close to that of the physicians, although the LR tool definitely performed better than the decision tree. There were a number of differences in the performance of the two methods, shedding light on their strengths and weaknesses.