The Updated Mouse Universal Genotyping Array Bioinformatic Pipeline Improves Genetic QC in Laboratory Mice.

The MiniMUGA genotyping array is a popular tool for genetic QC of laboratory mice and genotyping of samples from most types of experimental crosses involving laboratory strains, particularly for reduced complexity crosses. The content of the production version of the MiniMUGA array is fixed; however, there is the opportunity to improve array's performance and the associated report's usefulness by leveraging thousands of samples genotyped since the initial description of MiniMUGA in 2020. Here we report our efforts to update and improve marker annotation, increase the number and the reliability of the consensus genotypes for inbred strains and increase the number of constructs that can reliably be detected with MiniMUGA. In addition, we have implemented key changes in the informatics pipeline to identify and quantify the contribution of specific genetic backgrounds to the makeup of a given sample, remove arbitrary thresholds, include the Y Chromosome and mitochondrial genome in the ideogram, and improve robust detection of the presence of commercially available substrains based on diagnostic alleles. Finally, we have made changes to the layout of the report, to simplify the interpretation and completeness of the analysis and added a table summarizing the ideogram. We believe that these changes will be of general interest to the mouse research community and will be instrumental in our goal of improving the rigor and reproducibility of mouse-based biomedical research.

Patient-reported barriers to prenatal diagnosis of congenital heart defects: A mixed-methods study.

OBJECTIVE: To ascertain patient-reported, modifiable barriers to prenatal diagnosis of congenital heart defects (CHDs). METHODS: This was a mixed-methods study among caretakers of infants who received congenital heart surgery from 2019 to 2020 in the Chicagoland area. Quantitative variables measuring sociodemographic characteristics and prenatal care utilization, and qualitative data pertaining to patient-reported barriers to prenatal diagnosis were collected from electronic health records and semi-structured phone surveys. Thematic analysis was performed using a convergent parallel approach. RESULTS: In total, 160 caretakers completed the survey, 438 were eligible for survey, and 49 (31%) received prenatal care during the COVID-19 pandemic. When comparing respondents and non-respondents, there was a lower prevalence of maternal Hispanic ethnicity and a higher prevalence of non-English/Spanish-speaking households. Of all respondents, 34% reported an undetected CHD on ultrasound or echocardiogram, while 79% reported at least one barrier to prenatal diagnosis related to social determinants of health. Among those social barriers, the most common were difficulty with appointment scheduling (n = 12, 9.5%), far distance to care/lack of access to transportation (n = 12, 9.5%) and difficulty getting time off work to attend appointments (n = 6, 4.8%). The latter two barriers were correlated. CONCLUSION: While technical improvements in the detection of CHDs remain an important area of research, it is equally critical to produce evidence for interventions that mitigate barriers to prenatal diagnosis due to social determinants of health.

Adjusting for Congenital Heart Surgery Risk Using Administrative Data.

BACKGROUND: Congenital heart surgery (CHS) encompasses a heterogeneous population of patients and surgeries. Risk standardization models that adjust for patient and procedural characteristics can allow for collective study of these disparate patients and procedures. OBJECTIVES: We sought to develop a risk-adjustment model for CHS using the newly developed Risk Stratification for Congenital Heart Surgery for ICD-10 Administrative Data (RACHS-2) methodology. METHODS: Within the Kids' Inpatient Database 2019, we identified all CHSs that could be assigned a RACHS-2 score. Hierarchical logistic regression (clustered on hospital) was used to identify patient and procedural characteristics associated with in-hospital mortality. Model validation was performed using data from 24 State Inpatient Databases during 2017. RESULTS: Of 5,902,538 total weighted hospital discharges in the Kids' Inpatient Database 2019, 22,310 pediatric cardiac surgeries were identified and assigned a RACHS-2 score. In-hospital mortality occurred in 543 (2.4%) of cases. Using only RACHS-2, the mortality mode had a C-statistic of 0.81 that improved to 0.83 with the addition of age. A final multivariable model inclusive of RACHS-2, age, payer, and presence of a complex chronic condition outside of congenital heart disease further improved model discrimination to 0.87 (P < 0.001). Discrimination in the validation cohort was also very good with a C-statistic of 0.83. CONCLUSIONS: We created and validated a risk-adjustment model for CHS that accounts for patient and procedural characteristics associated with in-hospital mortality available in administrative data, including the newly developed RACHS-2. Our risk model will be critical for use in health services research and quality improvement initiatives.

Chronic Medication Burden After Cardiac Surgery for Pediatric Medicaid Beneficiaries.

BACKGROUND: Congenital heart defects are the most common and resource-intensive birth defects. As children with congenital heart defects increasingly survive beyond early childhood, it is imperative to understand longitudinal disease burden. OBJECTIVES: The purpose of this study was to examine chronic outpatient prescription medication use and expenditures for New York State pediatric Medicaid enrollees, comparing children who undergo cardiac surgery (cardiac enrollees) and the general pediatric population. METHODS: This was a retrospective cohort study of all Medicaid enrollees age <18 years using the New York State Congenital Heart Surgery Collaborative for Longitudinal Outcomes and Utilization of Resources database (2006-2019). Primary outcomes were total chronic medications per person-year, enrollees per 100 person-years using ≥1 and ≥3 medications, and medication expenditures per person-year. We described and compared outcomes between cardiac enrollees and the general pediatric population. Among cardiac enrollees, multivariable regression examined associations between outcomes and clinical characteristics. RESULTS: We included 5,459 unique children (32,131 person-years) who underwent cardiac surgery and 4.5 million children (22 million person-years) who did not. More than 4 in 10 children who underwent cardiac surgery used ≥1 chronic medication compared with approximately 1 in 10 children who did not have cardiac surgery. Medication expenditures were 10 times higher per person-year for cardiac compared with noncardiac enrollees. Among cardiac enrollees, disease severity was associated with chronic medication use; use was highest among infants; however, nearly one-half of adolescents used ≥1 chronic medication. CONCLUSIONS: Children who undergo cardiac surgery experience high medication burden that persists throughout childhood. Understanding chronic medication use can inform clinicians (both pediatricians and subspecialists) and policymakers, and ultimately the value of care for this medically complex population.

Association Between Prenatal Diagnosis and Age at Surgery for Noncritical and Critical Congenital Heart Defects.

BACKGROUND: The relationship between the prenatal diagnosis of congenital heart defects (CHDs) and age at CHD surgery is poorly understood, despite the known relationships between age at surgery and long-term outcomes. The objective of this study was to determine the associations between prenatal diagnosis of CHD and age at surgery, and whether these associations differ for critical and noncritical CHDs. METHODS: This is a cohort analysis of patients aged 0 to 9 years who received their initial cardiac surgery at Ann & Robert H. Lurie Children's Hospital of Chicago between 2015 and 2021 with prenatal diagnosis as the exposure variable. All data were obtained from the locally maintained Society of Thoracic Surgeons Congenital Heart Surgery Database at Lurie Children's Hospital. We used multivariable fixed effects regression models to estimate the strength of the association of prenatal diagnosis with age at surgery among patients with critical (surgery ≤60 days) and noncritical (surgery >60 days) CHDs. RESULTS: Of 1131 individuals who met inclusion criteria, 532 (47%) had a prenatal diagnosis, 428 (38%) had critical CHDs, 533 (47%) were female, and the median age at surgery was 119 days (interquartile range, 11-309 days). After controlling for demographics, comorbidities, and surgical complexity, the mean age at surgery was significantly younger in those with prenatally versus postnatally diagnosed critical CHD (7.1 days sooner, P<0.001) and noncritical CHDs (atrial septal defects [12.4 months sooner, P=0.037], ventricular septal defects [6.0 months sooner, P<0.003], and noncritical coarctation of the aorta [1.8 months sooner, P=0.010]). CONCLUSIONS: Younger age at CHD surgery, which is associated with postsurgical neurodevelopmental and physical outcomes, is significantly associated with prenatal CHD diagnosis. This relationship was identified for both critical and noncritical CHDs.

Long-Term Health Care Utilization After Cardiac Surgery in Children Covered Under Medicaid.

BACKGROUND: Understanding the longitudinal burden of health care expenditures and utilization after pediatric cardiac surgery is needed to counsel families, improve care, and reduce outcome inequities. OBJECTIVES: The purpose of this study was to describe and identify predictors of health care expenditures and utilization for Medicaid-insured pediatric cardiac surgical patients. METHODS: All Medicaid enrolled children age <18 years undergoing cardiac surgery in the New York State CHS-COLOUR database, from 2006 to 2019, were followed in Medicaid claims data through 2019. A matched cohort of children without cardiac surgical disease was identified as comparators. Expenditures and inpatient, primary care, subspecialist, and emergency department utilization were modeled using log-linear and Poisson regression models to assess associations between patient characteristics and outcomes. RESULTS: In 5,241 New York Medicaid-enrolled children, longitudinal health care expenditures and utilization for cardiac surgical patients exceeded noncardiac surgical comparators (cardiac surgical children: $15,500 ± $62,000 per month in year 1 and $1,600 ± $9,100 per month in year 5 vs noncardiac surgical children: $700 ± $6,600 per month in year 1 and $300 ± $2,200 per month in year 5). Children after cardiac surgery spent 52.9 days in hospitals and doctors' offices in the first postoperative year and 90.5 days over 5 years. Being Hispanic, compared with non-Hispanic White, was associated with having more emergency department visits, inpatient admissions, and subspecialist visits in years 2 to 5, but fewer primary care visits and greater 5-year mortality. CONCLUSIONS: Children after cardiac surgery have significant longitudinal health care needs, even among those with less severe cardiac disease. Health care utilization differed by race/ethnicity, although mechanisms driving disparities should be investigated further.

Correlation Between Right Ventricular Echocardiography Measurements and Functional Capacity in Patients With Pulmonary Arterial Hypertension.

BACKGROUND: Accelerometry is an emerging option for real-time evaluation of functional capacity in patients with pulmonary arterial hypertension (PAH). This prospective pilot study assesses the relationship between functional capacity by accelerometry and right ventricular measurements on echocardiography for this high-risk cohort. METHODS: Patients with PAH were prospectively enrolled and underwent 6-Minute Walk Test and cardiopulmonary exercise testing. They were given a Fitbit, which collected steps and sedentary time per day. Echocardiographic data included right ventricular global longitudinal, free wall, and septal strain; tricuspid regurgitant peak velocity; tricuspid annular plane systolic excursion; tricuspid annular plane systolic velocity; right ventricular myocardial performance index; and pulmonary artery acceleration time. Pairwise correlations were performed. RESULTS: The final analysis included 22 patients aged 13 to 59 years. Tricuspid regurgitant peak velocity had a negative correlation with 6-Minute Walk Test (r = -0.58, P = .02), peak oxygen consumption on exercise testing (r = -0.56, P = .03), and average daily steps on accelerometry (r = -0.59, P = .03), but a positive correlation with median sedentary time on accelerometry (r = 0.64, P = .02). Pulmonary artery acceleration time positively correlated with peak oxygen consumption on exercise testing (r = 0.64, P = .002). There was no correlation between right ventricular strain measurements and functional capacity testing. CONCLUSION: In this pilot study, tricuspid regurgitant jet and pulmonary artery acceleration time were the echocardiographic variables that correlated most with accelerometry data. With further echocardiographic validation, accelerometry can be a useful, noninvasive, and cost-effective tool to monitor disease progression in patients with PAH.

Disparities in surgical outcomes of neonates with congenital heart disease across regions, centers, and populations.

OBJECTIVE: To summarize existing literature on neonatal disparities in congenital heart disease surgical outcomes and identify potential policies to address these disparities. FINDING: Disparities in outcomes for neonatal congenital heart surgery were largely published under four domains: race/ethnicity, insurance type, neighborhood/socioeconomic status, and cardiac center characteristics. While existing research identifies associations between these domains and mortality, more nuanced analyses are emerging to understand the mediators between these domains and other non-mortality outcomes, as well as potential interventions and policies to reduce disparities. A broader look into social determinants of health (SDOH), prenatal diagnosis, proximity of birth to a cardiac surgical center, and post-surgical outpatient and neurodevelopmental follow-up may accelerate interventions to mitigate disparities in outcomes. CONCLUSION: Understanding the mechanisms of how SDOH relate to neonatal surgical outcomes is paramount, as disparities research in neonatal congenital heart surgery continues to shift from identification and description, to intervention and policy.

Shear wave elastography: the relationship of the cervical stiffness with gestational age and cervical length- a feasibility study.

OBJECTIVES: To standardize the measurement of shear wave elastography for assessment of cervical stiffness and its relationship with gestational age and cervical length. METHODS: A prospective cross-sectional study was conducted from September 2017 to March 2019. Data from 125 unselected women (at 11-13 + 6, 18-22 and 24-28 weeks' gestation) and 55 high-risk women were analyzed for the study. Six regions of interest were evaluated for cervical elastography in the mid-sagittal position by transvaginal ultrasound. Statistical analyses were performed using R statistical language in R-studio. Delivery outcomes were recorded for each patient. RESULTS: The shear wave elastography was feasible with good intraoperator and interoperator reproducibility. The endocervical canal and anterior lip internal position had the highest reproducibility (ICC-0.82, 0.75). Shear wave speed was significantly higher in all internal os regions than the external os. There was a statistically significant negative linear relationship of shear wave speed with the gestational age. There was a weak positive relationship between shear wave speed and cervical length. There was no difference between pregnancies with and without spontaneous preterm delivery in shear wave speed measurements and cervical length, although numbers were small for statistical analysis. The internal os of the large loop excision of the transformation zone group was stiffer than the normal population. CONCLUSION: Cervical elastography is feasible and effectively evaluates the tensile properties of the cervix during pregnancy. The most reproducible measurements were obtained at the anterior lip of the internal cervical os. Combining evaluation of cervical elasticity and length might further improve the identification of women at risk of preterm delivery. Currently, technical issues hinder the practical application of shear wave elastography in the clinical setting and require further research and development of the imaging modality.

Risk Stratification for Congenital Heart Surgery for ICD-10 Administrative Data (RACHS-2).

BACKGROUND: As the cardiac community strives to improve outcomes, accurate methods of risk stratification are imperative. Since adoption of International Classification of Disease-10th Revision (ICD-10) in 2015, there is no published method for congenital heart surgery risk stratification for administrative data. OBJECTIVES: This study sought to develop an empirically derived, publicly available Risk Stratification for Congenital Heart Surgery (RACHS-2) tool for ICD-10 administrative data. METHODS: The RACHS-2 stratification system was iteratively and empirically refined in a training dataset of Pediatric Health Information Systems claims to optimize sensitivity and specificity compared with corresponding locally held Society of Thoracic Surgeons-Congenital Heart Surgery (STS-CHS) clinical registry data. The tool was validated in a second administrative data source: New York State Medicaid claims. Logistic regression was used to compare the ability of RACHS-2 in administrative data to predict operative mortality vs STAT Mortality Categories in registry data. RESULTS: The RACHS-2 system captured 99.6% of total congenital heart surgery registry cases, with 1.0% false positives. RACHS-2 predicted operative mortality in both training and validation administrative datasets similarly to STAT Mortality Categories in registry data. C-statistics for models for operative mortality in training and validation administrative datasets-adjusted for RACHS-2-were 0.76 and 0.84 (95% CI: 0.72-0.80 and 0.80-0.89); C-statistics for models for operative mortality-adjusted for STAT Mortality Categories-in corresponding clinical registry data were 0.75 and 0.84 (95% CI: 0.71-0.79 and 0.79-0.89). CONCLUSIONS: RACHS-2 is a risk stratification system for pediatric cardiac surgery for ICD-10 administrative data, validated in 2 administrative-registry-linked datasets. Statistical code is publicly available upon request.

Improving Longitudinal Outcomes, Efficiency, and Equity in the Care of Patients With Congenital Heart Disease.

BACKGROUND: Longitudinal follow-up, resource utilization, and health disparities are top congenital heart research and care priorities. Medicaid claims include longitudinal data on inpatient, outpatient, emergency, pharmacy, rehabilitation, home health utilization, and social determinants of health-including mother-infant pairs. OBJECTIVES: The New York Congenital Heart Surgeons Collaborative for Longitudinal Outcomes and Utilization of Resources linked robust clinical details from locally held state and national registries from 10 of 11 New York congenital heart centers to Medicaid claims, building a novel, statewide mechanism for longitudinal assessment of outcomes, expenditures, and health inequities. METHODS: The authors included all children <18 years of age undergoing cardiac surgery in The Society of Thoracic Surgeons Congenital Heart Surgery Database or the New York State Pediatric Congenital Cardiac Surgery Registry from 10 of 11 New York centers, 2006 to 2019. Data were linked via iterative, ranked deterministic matching on direct identifiers. Match rates were calculated and compared. Proportions of the linked cohort trackable over 3, 5, and 10 years were described. RESULTS: Of 14,097 registry cases, 59% (n = 8,322) reported Medicaid use. Of these, 7,414 were linked to New York claims, at an 89% match rate. Of matched cases, the authors tracked 79%, 74%, and 65% of children over 3, 5, and 10 years when requiring near-continuous Medicaid enrollment. Allowing more lenient enrollment criteria, the authors tracked 86%, 82%, and 76%, respectively. Mortality over this time was 7.7%, 8.4%, and 10.0%, respectively. Manual validation revealed ∼100% true matches. CONCLUSIONS: This establishes a novel statewide data resource for assessment of longitudinal outcome, health expenditure, and disparities for children with congenital heart disease.

Bidirectional control of infant rat social behavior via dopaminergic innervation of the basolateral amygdala.

Social interaction deficits seen in psychiatric disorders emerge in early-life and are most closely linked to aberrant neural circuit function. Due to technical limitations, we have limited understanding of how typical versus pathological social behavior circuits develop. Using a suite of invasive procedures in awake, behaving infant rats, including optogenetics, microdialysis, and microinfusions, we dissected the circuits controlling the gradual increase in social behavior deficits following two complementary procedures-naturalistic harsh maternal care and repeated shock alone or with an anesthetized mother. Whether the mother was the source of the adversity (naturalistic Scarcity-Adversity) or merely present during the adversity (repeated shock with mom), both conditions elevated basolateral amygdala (BLA) dopamine, which was necessary and sufficient in initiating social behavior pathology. This did not occur when pups experienced adversity alone. These data highlight the unique impact of social adversity as causal in producing mesolimbic dopamine circuit dysfunction and aberrant social behavior.

Center Reputation and Experience Relate to Industry Payments to Congenital Heart Disease Providers.

BACKGROUND: The Physician Payments Sunshine Act was enacted to understand financial relationships with industry that might influence provider decisions. We investigated how industry payments within the congenital heart community relate to experience and reputation. METHODS: Congenital cardiothoracic surgeons and pediatric cardiologists were identified from the Open Payments Database. All payments from 2013 through 2017 were matched to affiliated hospitals' U.S. News & World Report (USNWR) rankings, The Society of Thoracic Surgeons-Congenital Heart Surgery Public Reporting Star Ratings, and Optum Center of Excellence (COE) designation. Surgeon payments were linked to years since terminal training. Univariable analyses were conducted. RESULTS: The median payment amount per surgeon ($71; interquartile range [IQR], $41-$99) was nearly double the median payment amount per cardiologist ($41; IQR, $18-$84; P < .05). For surgeons, median individual payment was 56% higher to payees at USNWR top 10 children's hospitals ($100; IQR, $28-$203) vs all others ($64; IQR, $23-$140; P < .001). For cardiologists, median individual payment was 26% higher to payees at USNWR top 10 children's hospitals ($73; IQR, $28-$197) vs all others ($58; IQR, $19-$140; P < .001). Findings were similar across The Society of Thoracic Surgeons-Congenital Heart Surgery star rankings and Optum Center of Excellence groups. By surgeon experience, surgeons 0 to 6 years posttraining (first quartile) received the highest number of median payments per surgeon (17 payments; IQR, 6.5-28 payments; P < .001). Surgeons 21 to 44 years posttraining (fourth quartile) received the lowest median individual payment ($51; IQR, $20-132; P < .001). CONCLUSIONS: Industry payments vary by hospital reputation and provider experience. Such biases must be understood for self-governance and the delineation of conflict of interest policies that balance industry relationships with clinical innovation.

Cardiac workup and monitoring in hospitalised children with COVID- 19.

Approximately, 1.7 million individuals in the United States have been infected with SARS-CoV-2, the virus responsible for the novel coronavirus disease-2019 (COVID-19). This has disproportionately impacted adults, but many children have been infected and hospitalised as well. To date, there is not much information published addressing the cardiac workup and monitoring of children with COVID-19. Here, we share the approach to the cardiac workup and monitoring utilised at a large congenital heart centre in New York City, the epicentre of the COVID-19 pandemic in the United States.

Magnetorheological Gel Mimicking Cervical Ripening as a Potential Model for Evaluating Shear Wave Elastography.

The mechanical characteristics of tissue can reflect its biochemical content and, therefore, be a powerful tool in the diagnosis of diseases. Many different methods have been developed for testing the mechanical properties of tissue, such as aspiration, indentation and shear wave elastography. Soft tissues are, however, more complex in behaviour than current commercial tissue-mimicking materials and the models used in measurement methods. Complex behaviours of the tissue include anisotropy and heterogeneous elasticity. The oversimplified models assumed in different measuring methods often neglect the effects of these behaviours, resulting in inaccuracies. The aim of this study was to develop a tissue-mimicking material able to capture the complexity of tissue mechanical behaviour. It will be used to improve mechanical property measuring methods by quantitatively determining how complexities in tissue behaviour affect the measurements made and evaluating the effectiveness of methods designed to overcome it, and will be used to train users for consistency in measurement. The tissue-mimicking material designed in this study focuses on the mechanical properties of the cervix as measured by shear wave elastography. The characteristic behaviours of cervical tissues highlighted are anisotropy, a wide range of elasticity that changes with gestational age and an elasticity gradient across the tissue. Magnetorheological gels were used as their elastic properties can be tuned with the application of magnetic fields. The sample was simulated with the finite-element software COMSOL before being tested by shear wave elastography and the INSTRON universal material testing machine. It had an elasticity range of 6.75-11.06 kPa, which is similar to that of cervical tissue. It was determined that a change in the orientation of the probe with respect to the orientation of anisotropy can cause up to a 30 % increase in measured elasticity. There was a 16% decrease in elasticity across the sample.

Elevated infant cortisol is necessary but not sufficient for transmission of environmental risk to infant social development: Cross-species evidence of mother-infant physiological social transmission.

Environmental adversity increases child susceptibility to disrupted developmental outcomes, but the mechanisms by which adversity can shape development remain unclear. A translational cross-species approach was used to examine stress-mediated pathways by which poverty-related adversity can influence infant social development. Findings from a longitudinal sample of low-income mother-infant dyads indicated that infant cortisol (CORT) on its own did not mediate relations between early-life scarcity-adversity exposure and later infant behavior in a mother-child interaction task. However, maternal CORT through infant CORT served as a mediating pathway, even when controlling for parenting behavior. Findings using a rodent "scarcity-adversity" model indicated that pharmacologically blocking pup corticosterone (CORT, rodent equivalent to cortisol) in the presence of a stressed mother causally prevented social transmission of scarcity-adversity effects on pup social behavior. Furthermore, pharmacologically increasing pup CORT without the mother present was not sufficient to disrupt pup social behavior. Integration of our cross-species results suggests that elevated infant CORT may be necessary, but without elevated caregiver CORT, may not be sufficient in mediating the effects of environmental adversity on development. These findings underscore the importance of considering infant stress physiology in relation to the broader social context, including caregiver stress physiology, in research and interventional efforts.

Minimum Travel Distance Among Publicly Insured Infants with Severe Congenital Heart Disease: Potential Impact of In-state Restrictions.

Travel distance to surgical centers may be increased when coverage restrictions prevent children with congenital heart disease (CHD) from receiving care at out-of-state congenital heart surgery centers. We estimated the minimum travel distance to congenital heart surgery centers among publicly insured infants with time-sensitive CHD surgical needs, under two different scenarios: if they were and were not restricted to in-state centers. Using 2012 Medicaid Analytic eXtract data from 40 states, we identified 4598 infants with CHD that require surgery in the first year of life. We calculated the minimum travel distance between patients' homes and the nearest cardiac surgery center, assuming patients were and were not restricted to in-state centers. We used linear regression to identify demographic predictors of distance under both scenarios. When patients were not restricted to in-state centers, mean minimum travel distance was 43.7 miles, compared to 54.1 miles when they were restricted. For 5.9% of patients, the difference in travel distance under the two scenarios exceeded 50 miles. In six states, the difference in mean minimum travel distance exceeded 20 miles. Under both scenarios, distance was positively predicted by rural status, residence in middle-income zip codes, and white/non-Hispanic or American Indian/Alaskan Native race/ethnicity. For some publicly insured infants with severe CHD, facilitating the receipt of out-of-state care could mitigate access barriers. Existing efforts to regionalize care at fewer centers should be designed to avoid exacerbating access barriers among publicly insured CHD patients.