Electroencephalogram-based machine learning models to predict neurologic outcome after cardiac arrest: A systematic review.

AIM OF THE REVIEW: The primary aim of this systematic review was to investigate the most common electroencephalogram (EEG)-based machine learning (ML) model with the highest Area Under Receiver Operating Characteristic Curve (AUC) in two ML categories, conventional ML and Deep Neural Network (DNN), to predict the neurologic outcomes after cardiac arrest; the secondary aim was to investigate common EEG features applied to ML models. METHODS: Systematic search of medical literature from PubMed and engineering literature from Compendex up to June 2, 2023. One reviewer screened studies that used EEG-based ML models to predict the neurologic outcomes after cardiac arrest. Four reviewers validated that the studies met selection criteria. Nine variables were manually extracted. The top-five common EEG features were calculated. We evaluated each study's risk of bias using the Quality in Prognosis Studies guideline. RESULTS: Out of 351 identified studies, 17 studies met the inclusion criteria. Random Forest (RF) (n = 7) was the most common ML model in the conventional ML category (n = 11), followed by Convolutional Neural Network (CNN) (n = 4) in the DNN category (n = 6). The AUCs for RF ranged between 0.8 and 0.97, while CNN had AUCs between 0.7 and 0.92. The top-three commonly used EEG features were band power (n = 12), Shannon's Entropy (n = 11), burst-suppression ratio (n = 9). CONCLUSIONS: RF and CNN were the two most common ML models with the highest AUCs for predicting the neurologic outcomes after cardiac arrest. Using a multimodal model that combines EEG features and electronic health record data may further improve prognostic performance.

A Narrative Review of Multiinstitutional Data Registries of Pediatric Congenital Heart Disease in Pediatric Cardiac Anesthesia and Critical Care Medicine.

Congenital heart disease (CHD) is one of the most common birth anomalies. While the care of children with CHD has improved over recent decades, children with CHD who undergo general anesthesia remain at increased risk for morbidity and mortality. Electronic health record systems have enabled institutions to combine data on the management and outcomes of children with CHD in multicenter registries. The application of descriptive analytics methods to these data can improve clinicians' understanding and care of children with CHD. This narrative review covers efforts to leverage multicenter data registries relevant to pediatric cardiac anesthesia and critical care to improve the care of children with CHD.

Red blood cell storage duration and peri-operative outcomes in paediatric cardiac surgery.

BACKGROUND: Prior research on red blood cell (RBC) storage duration and clinical outcomes in paediatric cardiac surgery has shown conflicting results. The purpose of this study was to evaluate whether blood stored for a longer duration is harmful in these patients. METHODS: We performed a retrospective cohort study of paediatric patients undergoing cardiac surgery at our institution between January 2011 and June 2015. Patients were stratified based on whether they were transfused RBCs stored for ≤15 days (fresher blood) or >15 days (older blood). The primary outcome was composite morbidity, with prolonged length of stay (LOS) as a secondary outcome. Subgroup analyses were performed after stratification by RBC transfusion volume (≤2 vs. >2 RBC units). Multivariable logistic regression models were used to assess the impact of RBC storage duration on composite morbidity and prolonged LOS. RESULTS: Of 461 patients, 122 (26·5%) received fresher blood and 339 (73·5%) received older blood. The overall rate of composite morbidity was 18·0% (n = 22) for patients receiving fresher blood and 13·6% (n = 46) for patients receiving older blood (P = 0·24). In the risk-adjusted model, patients receiving older blood did not exhibit an increased risk of composite morbidity (OR: 0·74, 95% CI: 0·37-1·47, P = 0·40) or prolonged LOS (OR: 0·72, 95% CI: 0·38-1·35, P = 0·30) compared to patients receiving fresher blood. Similar results were seen after stratification by RBC transfusion volume. CONCLUSIONS: Transfusing RBCs stored for a longer duration was not associated with an increased risk of morbidity or prolonged LOS in paediatric cardiac surgery patients.

Utility of Follow-Up Annual Echocardiograms in Patients With Complete Transposition of the Great Arteries After Arterial Switch Operations.

The arterial switch operation (ASO) in complete transposition of the great arteries (TGA) has increased long-term survival. Annual follow-up echocardiograms are recommended, but evidence-based guidelines do not exist. We sought to assess how often a patient with TGA after ASO who had no symptoms or change in physical exam underwent an intervention based solely on echocardiographic changes. We retrospectively reviewed all records from patients with TGA and a history of ASO followed at our institution between November 1983 and January 2015. Changes in echocardiograms resulting in hospital admission, significant medication change, interventional catheterization, or surgical procedure were identified through the surgical and cardiac catheterization laboratory databases and patient charts. These changes were referred to as an actionable change (AC). Interventions were defined as being driven by either clinical (change in physical exam, patient and/or parental concerns) or echocardiographic findings. A total of 1,792 echocardiograms from 149 patients were reviewed. Median number of echocardiograms per patient was 12 (1 to 34). Of the 1,792 echocardiograms, 20 (1.12%) were associated with AC. The most common intervention for an AC was cardiac catheterization (13 of 20, 65%). Most AC (15 of 20, 75%) occurred in the first decade after ASO. AC occurred in 83% (5 of 6) of those with a history of both ASO and arch repair. Annual echocardiograms in patients with TGA after ASO are rarely useful and are unnecessary. In conclusion, decreasing surveillance of asymptomatic patients to biennial follow-up echocardiograms in asymptomatic patients without physical examination changes is safe and would decrease medical expenses.

Frequency of Development of Aortic Valve Disease in Unrepaired Perimembranous Ventricular Septal Defects.

We sought to determine the natural history of aortic valve disease in patients with unrepaired perimembranous ventricular septal defects (pVSDs) and to identify echocardiographic parameters predictive of increased risk of surgical repair of pVSD because of aortic valve disease. We retrospectively analyzed all echocardiograms of patients with a diagnosis of pVSD at our institution from January 1999 to January 2015. All available echocardiographic data were collected. Patients were excluded if there was another structural cardiac anomaly other than bicuspid aortic valve, small patent foramen ovale, or ductus arteriosus. The prevalences of aortic valve prolapse and regurgitation, as well as aortic valve disease progression, were determined. A total of 2,114 echocardiograms from 657 patients with unrepaired pVSD were reviewed. Median age at the time of echocardiogram was 1.9 years (interquartile range [IQR] 0.2 to 5.4). Median duration of follow-up was 1.7 years (IQR 0.2 to 7.4). pVSD-associated aortic valve disease prompted surgical intervention in 1.5% (10 of 657) of patients. Median age at the time of surgery was 4.8 years (IQR 1.7 to 8.4). A pVSD-to-aortic annulus diameter ratio of 0.66 ± 0.05 was present in 90% (9 of 10) of patients who underwent surgical closure because of pVSD-associated aortic valve disease. In conclusion, pVSD-associated aortic valve disease is uncommon, and progression of aortic regurgitation is rare. These data suggest that the majority of patients with pVSD do not require frequent follow-up and that frequent follow-up can be saved for a subset with echocardiographic markers placing them at higher risk of aortic valve diseases.

Removal of a retained intracardiac radiolucent guidewire fragment using an Atrieve™ vascular snare using combined fluoroscopy and transesophageal echocardiography guidance in an infant.

Retained intravascular foreign body is a well-known complication of central venous access placement in children as well as adults. Most of these foreign bodies are radio-opaque and hence are removed under fluoroscopy guidance. In our case, we describe the removal of an intracardiac radiolucent foreign body in an infant utilizing a combination technique - transesophageal echocardiogram and fluoroscopy.

Epidemiology and outcomes of cardiac arrest among children with Down Syndrome: a multicenter analysis.

BACKGROUND: With the increasing prevalence of Down Syndrome, it is unknown if children with Down Syndrome are associated with increased incidence of cardiac arrest and poor outcomes after cardiac arrest. The objective of this study was to evaluate the epidemiology of cardiac arrest and mortality after cardiac arrest among critically ill children with and without Down Syndrome. METHODS: Patients ≤18 years admitted at a Pediatric Health Information Systems (PHIS) participating Intensive Care Unit were included (2004-2014). Multivariable logistic regression models were fitted to evaluate association of Down Syndrome with study outcomes after adjusting for patient and center characteristics. RESULTS: A total of 849,250 patients from 44 centers were included. Of the 25,143 patients with Down Syndrome, cardiac arrest was noted among 568 (2.3%) patients with an associated mortality at hospital discharge of 248 (43.6%) patients. In contrast, of the 824,107 patients without Down Syndrome, cardiac arrest was noted among 15,822 (1.9%) patients with an associated mortality at hospital discharge of 7775 (49.1%) patients. In adjusted models, patients with Down Syndrome had a higher likelihood of having cardiac arrest as compared to patients without Down Syndrome (with vs. without Down, OR: 1.14, 95% CI: 1.03-1.25, P=0.01). Despite having a higher likelihood of cardiac arrest, patients with Down Syndrome were associated with a lower mortality after cardiac arrest (OR: 0.78, 95% CI: 0.63-0.96, P=0.02). CONCLUSIONS: Both incidence of cardiac arrest, and mortality at hospital discharge in those with cardiac arrest vary substantially in children with and without Down Syndrome.

Is Administration of Nitric Oxide During Extracorporeal Membrane Oxygenation Associated With Improved Patient Survival?

OBJECTIVE: To evaluate the outcomes associated with the use of inhaled nitric oxide during extracorporeal membrane oxygenation. DESIGN: Post hoc analysis of data from an existing administrative national database, Pediatric Health Information system (2004-2014). Multivariable logistic regression models were fitted to study the effect of inhaled nitric oxide during extracorporeal membrane oxygenation on study outcomes. SETTING: Forty-two children's hospitals across the United States. PATIENTS: Patients in the age group from 1 day through 18 years admitted to an ICU who received extracorporeal membrane oxygenation during their hospital stay were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In total, 6,419 patients qualified for inclusion. Of these, inhaled nitric oxide was used among 3,629 patients during extracorporeal membrane oxygenation run. Approximately one half of the study patients received inhaled nitric oxide at extracorporeal membrane oxygenation initiation. The proportion of patients receiving inhaled nitric oxide during extracorporeal membrane oxygenation decreased with increasing duration of extracorporeal membrane oxygenation. After adjusting for patient characteristics and center variables, use of inhaled nitric oxide was not associated with any survival benefit. However, higher proportion of patients receiving inhaled nitric oxide were associated with prolonged hospital length of stay and prolonged duration of extracorporeal membrane oxygenation. In adjusted models, the hospital charges were higher in the inhaled nitric oxide group. The median hospital costs among patients receiving inhaled nitric oxide were higher by $39,732 (95% CI, $31,074-48,390) as compared to the patients who did not receive inhaled nitric oxide, after adjusting for patient (including hospital length of stay) and center level variables. As the duration of inhaled nitric oxide therapy increased, proportion of patients with prolonged duration of extracorporeal membrane oxygenation and prolonged hospital length of stay increased. CONCLUSIONS: This large observational analysis of use of nitric oxide during extracorporeal membrane oxygenation calls into question the benefits of inhaled nitric oxide among patients receiving extracorporeal membrane oxygenation for pulmonary or cardiac failure. Given our inability to determine type of extracorporeal membrane oxygenation and control for severity of illness, these findings should be interpreted as exploratory.

Cardiac magnetic resonance imaging for the assessment of the myocardium after doxorubicin-based chemotherapy.

OBJECTIVES: Doxorubicin is associated with a cumulative dose-dependent nonischemic cardiomyopathy. Cardiac magnetic resonance imaging (cMRI) is able to examine both structural and functional components of the myocardium. Our aim was to assess the myocardial changes in non-Hodgkin lymphoma patients undergoing doxorubicin-based chemotherapy using cMRI. MATERIALS AND METHODS: cMRI examination was performed before and 3 months after chemotherapy. Experienced investigators interpreted each cMRI, and were blinded to all data. Left ventricular ejection fractions (LVEF), cardiac deformation, and delayed gadolinium enhancement (GD-DE) were quantified for each cMRI. The change between LVEF, GD-GE, and cardiac deformation parameters were compared between the 2 cMRI studies. A Δ LVEF≥10% was considered clinically relevant. The findings of GD-GE or changes in myocardial strain were analyzed as independent variables. RESULTS: All 10 patients enrolled received a cumulative dose of doxorubicin of 300 mg/m. A comparison of pretreatment and posttreatment cMRI demonstrated 5 (50%) patients with a ≥10% decrease in LVEF (median, -8.4%; range, 1% to -17%; P=0.004). Three patients had at least 1 new or progressive segment of GD-DE. The global circumferential strain was significantly lower in patients after treatment, as compared with values before treatment (P=0.018) and to normal controls (P=0.046). Patients after treatment also had significantly lower global longitudinal strain than controls (P=0.035), and longitudinal strain values that tended to decrease compared with pretreatment values (P=0.073). DISCUSSION: Our data suggests that cMRI has the ability to assess both early structural and functional myocardial changes in association with doxorubicin-based chemotherapy.

Combination of real time three-dimensional echocardiography with diagnostic catheterization to derive left ventricular pressure-volume relations.

AIMS: The aim of this study was to investigate the left ventricular (LV) myocardial contractility index-Emax using transesophageal real time three-dimensional echocardiography (RT3DE) combined with catheterization. METHODS: Transesophageal RT3DE (single beat, X7-2 × matrix, iE33, Philips) was used to obtain real time LV volumes in pigs. Volumes were integrated with LV pressures from conductance catheterization (CC) to create RT3DE pressure-volume relations. At the same time, CC was used for measuring conventional pressure-volume relations that served as reference. The slope Emax was determined from RT3DE and CC end-systolic pressure-volume relations. All measurements were made at rest and during dobutamine infusion. RESULTS: In six pigs, the mean ± SD (mmHg/mL) values were Emax-CC 1.86 ± 1.1 and Emax-RT3DE 1.78 ± 1.2 (P = 0.502) at baseline. On dobutamine, mean Emax-CC was 3.43 ± 1.5 and Emax-RT3DE 3.60 ± 1.23 (P = 0.171). Bland-Altman analysis showed good agreements between the RT3DE- and CC-derived Emax for measurements performed at baseline and on dobutamine. CONCLUSIONS: Emax can be determined from RT3DE integrated with catheterization-derived pressures. RT3DE is a promising method for enhancing clinical applicability of pressure-volume relations for assessment of myocardial contractility.

Validation of admittance computed left ventricular volumes against real-time three-dimensional echocardiography in the porcine heart.

The admittance and Wei's equation is a new technique for ventricular volumetry to determine pressure-volume relations that addresses traditional conductance-related issues of parallel conductance and field correction factor. These issues with conductance have prevented researchers from obtaining real-time absolute ventricular volumes. Moreover, the time-consuming steps involved in processing conductance catheter data warrant the need for a better catheter-based technique for ventricular volumetry. We aimed to compare the accuracy of left ventricular (LV) volumetry between the new admittance catheterization technique and transoesophageal real-time three-dimensional echocardiography (RT3DE) in a large-animal model. Eight anaesthetized pigs were used. A 7 French admittance catheter was positioned in the LV via the right carotid artery. The catheter was connected to an admittance control unit (ADVantage; Transonic Scisense Inc.), and data were recorded on a four-channel acquisition system (FA404; iWorx Systems). Admittance catheterization data and transoesophageal RT3DE (X7-2; Philips) data were simultaneously obtained with the animal ventilated, under neuromuscular blockade and monitored in baseline conditions and during dobutamine infusion. Left ventricular volumes measured from admittance catheterization (Labscribe; iWorx Systems) and RT3DE (Qlab; Philips) were compared. In a subset of four animals, admittance volumes were compared with those obtained from traditional conductance catheterization (MPVS Ultra; Millar Instruments). Of 37 sets of measurements compared, admittance- and RT3DE-derived LV volumes and ejection fractions at baseline and in the presence of dobutamine exhibited general agreement, with mean percentage intermethod differences of 10% for end-diastolic volumes, 14% for end-systolic volumes and 9% for ejection fraction; the respective intermethod differences between admittance and conductance in eight data sets compared were 11, 11 and 12%. Admittance volumes were generally higher than those obtained by RT3DE, especially among the larger ventricles. It is concluded that it is feasible to derive pressure-volume relations using admittance catheterization in large animals. This study demonstrated agreements between admittance and RT3DE to within 10-14% mean intermethod difference in the estimation of LV volumes. Further investigation will be required to examine the accuracy of volumes in largest ventricles, where intermethod divergence is greatest.

Functional maturation of left and right atrial systolic and diastolic performance in infants, children, and adolescents.

BACKGROUND: Left atrial (LA) function is an important modulator of left ventricular filling and has a prognostic role in adult heart failure, but pediatric data are limited. The aim of this study was to characterize the normal LA and right atrial (RA) strain (ε) and strain rate (SR) in infants and children. METHODS: Atrial ε and SR were prospectively investigated in 153 subjects using two-dimensional speckle-tracking echocardiography. High-frame rate, three-beat captures of LA (15-segment model; two-chamber, three-chamber, and four-chamber views) and RA (six-segment model; four-chamber view) were analyzed (Vivid 7, EchoPAC BT11). LA and RA segmental and global peak positive ε (εPos) and negative ε (εNeg) and peak positive SR, early negative SR, and late negative SR were measured. Linear and nonlinear regressions of ε and SR were performed with age and heart rate. Relationships of ε and SR with ventricular inflow Doppler and myocardial tissue Doppler indices were explored. RESULTS: The age range was 3 days to 20 years, and body surface area range from 0.17 to 2.3 m(2) for the study cohort. Mean global LA εPos, LA εNeg, RA εPos, and RA εNeg were 28 ± 9%, -16 ± 6%, 23 ± 9%, and -15 ± 6%, respectively. Positive correlations were found for global atrial εPos and εNeg with age (P < .001). A marked rate of changes in ε and SR was seen in the first year of life, reaching normal adult values by adolescence. Peak positive SR had a strong negative correlation with age, and early negative SR had a strong positive correlation with age (P < .001), while late negative SR was correlated nonlinearly. Heart rate and age both influenced all LA and RA ε and SR indices. CONCLUSIONS: Maturational changes in LA and RA ε and SR occur in normal children and are especially profound in infancy. Consequently, LA and RA performance indices must be interpreted in light of heart rate and age. Normal values and percentiles for atrial ε and SR reported here will provide a foundation for the study of pediatric atrial physiology and function in disease states.

Echocardiography and cardiac magnetic resonance-based feature tracking in the assessment of myocardial mechanics in tetralogy of Fallot: an intermodality comparison.

We investigated intermodality agreements of strains from two-dimensional echocardiography (2DE) and cardiac magnetic resonance (CMR) feature tracking (FT) in the assessment of right (RV) and left ventricular (LV) mechanics in tetralogy of Fallot (TOF). Patients were prospectively studied with 2DE and CMR performed contiguously. LV and RV strains were computed separately using 2DE and CMR-FT. Segmental and global longitudinal strains (GLS) for the LV and RV were measured from four-chamber views; LV radial (global radial strain [GRS]) and circumferential strains (GCS) measured from short-axis views. Intermodality and interobserver agreements were examined. In 40 patients (20 TOF, mean age 23 years and 20 adult controls), LV, GCS showed narrowest intermodality limits of agreement (mean percentage error 9.5%), followed by GLS (16.4%). RV GLS had mean intermodality difference of 25.7%. GLS and GCS had acceptable interobserver agreement for the LV and RV with both 2DE and CMR-FT, whereas GRS had high interobserver and intermodality variability. In conclusion, myocardial strains for the RV and LV derived using currently available 2DE and CMR-FT software are subject to considerable intermodality variability. For both modalities, LV GCS, LV GLS, and RV GLS are reproducible enough to warrant further investigation of incremental clinical merit.

Cardiovascular magnetic resonance myocardial feature tracking detects quantitative wall motion during dobutamine stress.

BACKGROUND: Dobutamine stress cardiovascular magnetic resonance (DS-CMR) is an established tool to assess hibernating myocardium and ischemia. Analysis is typically based on visual assessment with considerable operator dependency. CMR myocardial feature tracking (CMR-FT) is a recently introduced technique for tissue voxel motion tracking on standard steady-state free precession (SSFP) images to derive circumferential and radial myocardial mechanics.We sought to determine the feasibility and reproducibility of CMR-FT for quantitative wall motion assessment during intermediate dose DS-CMR. METHODS: 10 healthy subjects were studied at 1.5 Tesla. Myocardial strain parameters were derived from SSFP cine images using dedicated CMR-FT software (Diogenes MRI prototype; Tomtec; Germany). Right ventricular (RV) and left ventricular (LV) longitudinal strain (EllRV and EllLV) and LV long-axis radial strain (ErrLAX) were derived from a 4-chamber view at rest. LV short-axis circumferential strain (EccSAX) and ErrSAX; LV ejection fraction (EF) and volumes were analyzed at rest and during dobutamine stress (10 and 20 µg · kg⁻¹· min⁻¹). RESULTS: In all volunteers strain parameters could be derived from the SSFP images at rest and stress. EccSAX values showed significantly increased contraction with DSMR (rest: -24.1 ± 6.7; 10 µg: -32.7 ± 11.4; 20 µg: -39.2 ± 15.2; p < 0.05). ErrSAX increased significantly with dobutamine (rest: 19.6 ± 14.6; 10 µg: 31.8 ± 20.9; 20 µg: 42.4 ± 25.5; p < 0.05). In parallel with these changes; EF increased significantly with dobutamine (rest: 56.9 ± 4.4%; 10 µg: 70.7 ± 8.1; 20 µg: 76.8 ± 4.6; p < 0.05). Observer variability was best for LV circumferential strain (EccSAX ) and worst for RV longitudinal strain (EllRV) as determined by 95% confidence intervals of the difference. CONCLUSIONS: CMR-FT reliably detects quantitative wall motion and strain derived from SSFP cine imaging that corresponds to inotropic stimulation. The current implementation may need improvement to reduce observer-induced variance. Within a given CMR lab; this novel technique holds promise of easy and fast quantification of wall mechanics and strain.