Socioeconomic Status and Long-term Outcomes in Single Ventricle Heart Disease

BACKGROUND

Low socioeconomic status (SES) has emerged as an important risk factor for higher short-term mortality and neurodevelopmental outcomes in children with hypoplastic left heart syndrome and related anomalies; yet little is known about how SES affects these outcomes over the long-term.

METHODS

We linked data from the Single Ventricle Reconstruction trial to US Census Bureau data to analyze the relationship of neighborhood SES tertiles with mortality and transplantation, neurodevelopment, quality of life, and functional status at 5 and 6 years post-Norwood procedure (N = 525). Cox proportional hazards regression and linear regression were used to assess the association of SES with mortality and neurodevelopmental outcomes, respectively.

RESULTS

Patients in the lowest SES tertile were more likely to be racial minorities, older at stage 2 and Fontan procedures, and to have more complications and fewer cardiac catheterizations over follow-up (all P < .05) compared with patients in higher SES tertiles. Unadjusted mortality was highest for patients in the lowest SES tertile and lowest in the highest tertile (41% vs 29%, respectively; log-rank P = .027). Adjustment for patient birth and Norwood factors attenuated these differences slightly (P = .055). Patients in the lowest SES tertile reported lower functional status and lower fine motor, problem-solving, adaptive behavior, and communication skills at 6 years (all P < .05). These differences persisted after adjustment for baseline and post-Norwood factors. Quality of life did not differ by SES.

CONCLUSIONS

Among patients with hypoplastic left heart syndrome, those with low SES have worse neurodevelopmental and functional status outcomes at 6 years. These differences were not explained by other patient or clinical characteristics.

Theoretical Model for Delivery of Congenital Heart Surgery in the United States

BACKGROUND

Over 150 hospitals perform congenital heart surgery (CHS) in the United States. Many hospitals are close together, with a median patient travel distance of 38.5 miles. We began with a theoretical blank slate and used objective methodology guided by population density and volume thresholds to estimate the optimal number and locations of hospitals to provide CHS in the United States.

METHODS

Guided by published data, we estimated the number of CHS operations in the United States in to be 32,500 per year. We distributed patients geographically based on population density. Metropolitan Statistical Areas (population centers and surrounding areas with close economic/social ties) were used as potential hospital locations. Patients were assigned to the closest hospital location such that all hospitals had a CHS volume of ≥300 operations.

RESULTS

We estimated 57 hospitals could serve the contiguous United States. Median theoretical hospital volume after regionalization was 451 operations (interquartile range, 366-648). Median patient travel distance was 35.1 miles. Some patients (6396/31,895, 20%) traveled more than 100 miles.

CONCLUSIONS

Our model suggests the United States could be served by approximately 100 fewer CHS hospitals than currently exist. With hospitals optimally placed, patient travel burden would decrease. This model serves as a platform to improve care delivery by regionalization of CHS.

Improvement in Pediatric Cardiac Surgical Outcomes Through Interhospital Collaboration

BACKGROUND

Patients undergoing complex pediatric cardiac surgery remain at considerable risk of mortality and morbidity, and variation in outcomes exists across hospitals. The Pediatric Cardiac Critical Care Consortium (PC4) was formed to improve the quality of care for these patients through transparent data sharing and collaborative learning between participants.

OBJECTIVES

The purpose of this study was to determine whether outcomes improved over time within PC4.

METHODS

The study analyzed 19,600 hospitalizations (18 hospitals) in the PC4 clinical registry that included cardiovascular surgery from August 2014 to June 2018. The primary exposure was 2 years of PC4 participation; this provided adequate time for hospitals to accrue data and engage in collaborative learning. Aggregate case mix-adjusted outcomes were compared between the first 2 years of participation (baseline) and all months post-exposure. We also evaluated outcomes from the same era in a cohort of similar, non-PC4 hospitals.

RESULTS

During the baseline period, there was no evidence of improvement. We observed significant improvement in the post-exposure period versus baseline for post-operative intensive care unit mortality (2.1% vs. 2.7%; 22% relative reduction [RR]; p = 0.001), in-hospital mortality (2.5% vs. 3.3%; 24% RR; p = 0.001), major complications (10.1% vs. 11.5%; 12% RR; p < 0.001), intensive care unit length of stay (7.3 days vs. 7.7 days; 5% RR; p < 0.001), and duration of ventilation (61.3 h vs. 70.6 h; 13% RR; p = 0.01). Non-PC4 hospitals showed no significant improvement in mortality, complications, or hospital length of stay.

CONCLUSIONS

This analysis demonstrates improving cardiac surgical outcomes at children's hospitals participating in PC4. This change appears unrelated to secular improvement trends, and likely reflects PC4's commitment to transparency and collaboration.

Estimating Resource Utilization in Congenital Heart Surgery

BACKGROUND

Optimal methods to assess resource utilization in congenital heart surgery remain unclear. We compared traditional cost-to-charge ratio methods with newer standardized cost methods that aim to more directly assess resources consumed.

METHODS

Clinical data from The Society of Thoracic Surgeons Database were linked with resource use data from the Pediatric Health Information Systems Database (2010 to 2015). Standardized cost methods specific to the congenital heart surgery population were developed and compared with cost-to-charge ratio methods. Resource use in the overall population and variability across hospitals were described using hierarchical mixed effect models adjusting for case-mix.

RESULTS

Overall, 43 hospitals (65,331 patients) were included. There were minimal population-level differences in the distribution of resource use as estimated by the two methods. At the hospital level, there was less apparent variability in resource use across centers with the standardized cost vs cost-to-charge ratio method, overall (coefficient of variation 20% vs 25%) and across complexity (The Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery [STAT]) categories. When hospitals were categorized into tertiles by resource use, 33% changed classification depending on which resource use method was used (26% by one tertile and 7% by two tertiles).

CONCLUSIONS

In this first evaluation of standardized cost methodology in the congenital heart population, we found minimal differences vs traditional methods at the population level. At the hospital level, the magnitude of variation in resource use was less with standardized cost methods, and approximately one third of centers changed resource use categories depending on the methodology used. Because of these differences, care should be taken in future studies and in benchmarking and reporting efforts in selecting optimal methodology.

The Society of Thoracic Surgeons Congenital Heart Surgery Database: 2019 Update on Research

As the largest congenital and pediatric cardiac surgical clinical data registry in the world, The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS CHSD) serves as a platform for reporting of outcomes and for quality improvement. In addition, it is an important source of data for clinical research and for innovations related to quality measurement. Each year, several teams of investigators undertake analyses of data in the STS CHSD pertaining to the surgical management of specific diagnostic and procedural groups, or to specific processes of care, and their associations with patient characteristics and outcomes across centers participating in the STS CHSD. Additional ongoing projects involve the development of new or refined metrics for quality measurement and reporting of outcomes and center-level performance. The STS, through its Workforce for National Databases and the STS Research Center and Workforce on Research Development provides multiple pathways through which investigators may propose and perform outcomes research projects based on STS CHSD data. This report reviews research published within the past year.

The Quest for Precision Medicine: Unmeasured Patient Factors and Mortality After Congenital Heart Surgery

BACKGROUND

Emerging data across many fields suggest that unique patient characteristics can impact disease manifestation and response to therapy, supporting "precision medicine" approaches and more individualized and targeted therapeutic strategies. In children undergoing congenital heart surgery, current risk models primarily focus on the population level, and their utility in understanding precise characteristics that place individual patients at risk for poor outcome remains unclear.

METHODS

We analyzed index surgeries in the Pediatric Cardiac Critical Care Consortium (PC⁴) registry (August 2014 to May 2016) and utilized a previously constructed model containing patient factors typically included in in-hospital mortality risk models (age, weight, prematurity, chromosomal anomalies/syndromes, preoperative factors, The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery score). Partitioned variances based on a hierarchical generalized linear model were used to estimate the proportion of variation in mortality explained by these factors.

RESULTS

A total of 8406 operations (22 hospitals) were included. We found that only 30% of the total between-patient variation in mortality in our cohort was explained by the patient factors included in our model. Age, The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery score, and preoperative mechanical ventilation explained the greatest proportion of variation. Of the variation that remained unexplained, 95% was attributable to unmeasured patient factors. In stratified analyses, these results were consistent across patient subgroups.

CONCLUSIONS

Patient factors typically included in congenital heart surgery risk models explain only a small portion of total variation in mortality. A better understanding of other underrecognized factors is critical in further defining risk profiles and in developing more individualized and tailored therapeutic strategies.

Lessons learned in the use of clinical registry data in a multi-centre prospective study: the Pediatric Heart Network Residual Lesion Score Study

BACKGROUND

Using existing data from clinical registries to support clinical trials and other prospective studies has the potential to improve research efficiency. However, little has been reported about staff experiences and lessons learned from implementation of this method in pediatric cardiology.

OBJECTIVES

We describe the process of using existing registry data in the Pediatric Heart Network Residual Lesion Score Study, report stakeholders' perspectives, and provide recommendations to guide future studies using this methodology.

METHODS

The Residual Lesion Score Study, a 17-site prospective, observational study, piloted the use of existing local surgical registry data (collected for submission to the Society of Thoracic Surgeons-Congenital Heart Surgery Database) to supplement manual data collection. A survey regarding processes and perceptions was administered to study site and data coordinating center staff.

RESULTS

Survey response rate was 98% (54/55). Overall, 57% perceived that using registry data saved research staff time in the current study, and 74% perceived that it would save time in future studies; 55% noted significant upfront time in developing a methodology for extracting registry data. Survey recommendations included simplifying data extraction processes and tailoring to the needs of the study, understanding registry characteristics to maximise data quality and security, and involving all stakeholders in design and implementation processes.

CONCLUSIONS

Use of existing registry data was perceived to save time and promote efficiency. Consideration must be given to the upfront investment of time and resources needed. Ongoing efforts focussed on automating and centralising data management may aid in further optimising this methodology for future studies.

Cardiac Surgery in Patients With Trisomy 13 and 18: An Analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database

Background Congenital heart disease is common in patients with Trisomy 13 (T13) and Trisomy 18 (T18), but offering cardiac surgery to these patients has been controversial. We describe the landscape of surgical management across the United States, perioperative risk factors, and surgical outcomes in patients with T13 and T18. Methods and Results Patients in the Society of Thoracic Surgeons Congenital Heart Surgery Database with T13 and T18 who underwent cardiac surgery (2010-2017) were included. There were 343 operations (T13: n=73 and T18: n=270) performed on 304 patients. Among 125 hospitals, 87 (70%) performed at least 1 operation and 26 centers (30%) performed ≥5 T13/T18 operations. Operations spanned the full spectrum of complexity with 29% (98/343) being in the highest categories of estimated risk. The operative mortality rate was 15%, with a 56% complication rate. Preoperative mechanical ventilation was associated with an odds ratio of mortality >8 for both patients with T13 and T18 (both P<0.012) while presence of a gastrostomy tube (odds ratio, 0.3; P=0.03) or prior cardiac surgery (odds ratio, 0.2; P=0.02) was associated with better survival in patients with T18 but not patients with T13. Conclusions Data from this nationally representative sample indicate that most centers offer surgical intervention for both patients with T13 and T18, even in highly complex patients. However, the overall mortality rate was high in this select patient cohort. The association of preoperative mechanical ventilation with mortality suggests that this subset of patients with T13 and T18 should perhaps not be considered surgical candidates. This information is valuable to clinicians and families for counseling and deciding what interventions to offer.

Prenatal Diagnosis Influences Preoperative Status in Neonates with Congenital Heart Disease: An Analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

The early postnatal course for a newborn with critical congenital heart disease (CHD) can be negatively impacted if diagnosis is delayed. Despite this, there continues to be inconsistent evidence regarding potential benefits associated with prenatal diagnosis (PND) in neonates who undergo cardiac surgery. The objective of this study was to better define the impact of a PND on pre-operative morbidity by utilizing a large clinical database. Neonates (< 30 days) undergoing heart surgery from 2010 to 2014 and entered in the Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) were included. Multivariable logistic regression was used to evaluate the association between PND and a composite measure including nine major pre-operative risk factors. Co-variates were included to adjust for important patient characteristics (e.g., weight-for-age z-score, genetic syndromes, prematurity), case complexity, and center effects. Centers and patients with excess missing data for relevant co-variates were excluded. Included were 12,899 neonates undergoing surgery at 112 centers. Major pre-operative risk factors were present in 34% overall. By univariate analysis, PND was associated with a lower overall prevalence of major pre-operative risk factors. After adjusting for potential confounders, major pre-operative risk factors were less prevalent among neonates with PND compared to neonates without PND (adjusted OR 0.62, 95% CI 0.57-0.68, p < 0.001). A sensitivity analysis excluding neonates with genetic syndromes, non-cardiac anatomic abnormalities, and prematurity demonstrated similar findings (adjusted OR 0.55, 95% CI 0.49-0.61, p < 0.0001). Among neonates with CHD, prenatal diagnosis is associated with significantly lower rates of pre-operative risk factors for cardiac surgery. Further studies are needed to define association of these pre-operative benefits of a PND with longer term clinical outcomes.

Development of a Congenital Heart Surgery Composite Quality Metric: Part 2-Analytic Methods

BACKGROUND

We describe the statistical methods and results related to development of the first congenital heart surgery composite quality measure.

METHODS

The composite measure was developed using The Society of Thoracic Surgeons Congenital Heart Surgery Database (2012 to 2015), Bayesian hierarchical modeling, and the current Society of Thoracic Surgeons risk model for case-mix adjustment. It consists of a mortality domain (operative mortality) and morbidity domain (major complications and postoperative length of stay). We evaluated several potential weighting schemes and properties of the final composite measure, including reliability (signal-to-noise ratio) and hospital classification in various performance categories.

RESULTS

Overall, 100 hospitals (78,425 operations) were included. Each adjusted metric included in the composite varied across hospitals: operative mortality (median, 3.1%; 10th to 90th percentile, 2.1% to 4.4%) major complications (median 11.7%, 10th to 90th percentile, 6.4% to 17.4%), and length of stay (median, 7.0 days; 10th to 90th percentile, 5.9 to 8.2 days). In the final composite weighting scheme selected, mortality had the greatest influence, followed by major complications and length of stay (correlation with overall composite score of 0.87, 0.69, and 0.47, respectively). Reliability of the composite measure was 0.73 compared with 0.59 for mortality alone. The distribution of hospitals across composite measure performance categories (defined by whether the 95% credible interval overlapped The Society of Thoracic Surgeons average) was 75% (same as expected), 9% (worse than expected), and 16% (better than expected).

CONCLUSIONS

This congenital heart surgery composite measure incorporates aspects of both morbidity and mortality, has clinical face validity, and greater ability to discriminate hospital performance compared with mortality alone. Ongoing efforts will support the use of the composite measure in benchmarking and quality improvement activities.

Development of a Congenital Heart Surgery Composite Quality Metric: Part 1-Conceptual Framework

BACKGROUND

Current pediatric and congenital heart surgery quality measures focus on operative mortality, and numerous stakeholders are interested in more comprehensive measures. This report describes the background, rationale, and conceptual framework related to the development of the first composite quality metric in the field.

METHODS

A multidisciplinary panel reviewed methodology and framework related to quality measurement and several composite quality measures across adult cardiac surgery and other fields. The panel subsequently developed methodology and selected measures for a congenital heart surgery composite measure and reviewed potential advantages and limitations. Individual measures considered for potential inclusion in the composite were reviewed within the context of Donabedian's triad and the Institute of Medicine quality domains. Decisions were made through group consensus.

RESULTS

The final composite measure selected is comprised of two domains: (1) a mortality domain (operative mortality) and (2) a morbidity domain (the 6 major complications endorsed by The Society of Thoracic Surgeons and Congenital Heart Surgeons Society plus cardiac arrest, and postoperative length of stay). Potential advantages include the more comprehensive view of quality compared with mortality alone and improvements in discrimination of hospital performance through increasing the number of end points. Potential limitations include the lack of longer term outcomes and challenges related to case-mix adjustment.

CONCLUSIONS

We have applied and adapted conceptual framework and methodology related to composite quality measures across other fields to congenital heart surgery. The composite quality metric created is inclusive of both morbidity and mortality, and expands our view of quality in this patient population.

Variation in Implementation and Outcomes of Early Extubation Practices After Infant Cardiac Surgery

BACKGROUND

The Pediatric Heart Network Collaborative Learning Study (PHN CLS) increased early extubation after infant tetralogy of Fallot (TOF) and coarctation repair overall at participating sites through implementing a clinical practice guideline (CPG). We evaluated variability across sites in CPG implementation and outcomes.

METHODS

Patient characteristics and outcomes (time to extubation, length of stay [LOS]) were compared across sites, including pre-CPB to post-CPG changes. Semistructured interviews were analyzed to assess similarities and differences in implementation strategies across sites.

RESULTS

A total of 322 patients were included (4 active sites, 1 model site). Patient characteristics were similar across active sites, whereas pre-CPG median time to extubation varied from 15.4 to 35.5 hours. All active sites had a significant post-CPG decline (p < 0.001); however, there was variation in the post-CPG median time to extubation (0.3 to 5.3 hours, p = 0.01) and magnitude of change (-73.3% to -99.2%). Site A achieved the shortest post-CPG time to extubation and had the greatest percentage change. Two sites had significant decreases in medical ICU LOS in TOF patients; no hospital LOS changes were seen. All sites valued the collaborative learning strategy, site visits, CPG flexibility, and had similar core team composition. Site A used several unique strategies: inclusion of other staff and fellows, regular in-person data reviews, additional data collection, and creation of complementary protocols.

CONCLUSIONS

All PHN CLS sites successfully reduced time to extubation. The magnitude of change varied and may be partly explained by different CPG implementation strategies. These data can guide CPG dissemination and design of future improvement projects.

Sustainability of Infant Cardiac Surgery Early Extubation Practices After Implementation and Study

BACKGROUND

The Pediatric Heart Network Collaborative Learning Study (PHN CLS) successfully changed practice at four hospitals to increase the rate of early extubation within 6 hours after infant heart surgery. It is unknown whether this practice continued after study completion.

METHODS

We linked the PHN CLS dataset to the Pediatric Cardiac Critical Care Consortium registry to compare outcomes at four active hospitals between the study period (post-clinical practice guideline [CPG]) and the first year after study completion (follow-up) after a 3-month washout. Inclusion and exclusion criteria were the same across eras. Primary outcome was early extubation rate after tetralogy of Fallot or aortic coarctation repair. Secondary outcomes included time to first extubation and intensive care and hospital lengths of stay.

RESULTS

There were 121 patients in the post-CPG era and 139 patients in the follow-up era with no difference in patient characteristics or operation subtypes. Post-CPG early extubation rate declined from 67% to 30% in follow-up (p < 0.0001); time to first extubation increased (4.5 versus 13.5 hours, p < 0.0001). One hospital maintained the rate of early extubation (72% versus 67%), whereas the other three hospitals had significantly lower rates in follow-up (p < 0.02 for each). Intensive care (2.8 versus 2.9 days) and postoperative hospital (6 versus 5 days) stays did not differ between eras (p > 0.05 for both). Findings were consistent across operation subtypes.

CONCLUSIONS

Extubation practice in the first year of follow-up after the PHN CLS reverted toward prestudy levels. One of four hospitals maintained its early extubation strategy, suggesting that specific implementation and maintenance approaches may effectively sustain impact from quality initiatives.

Variation in care for infants undergoing the Stage II palliation for hypoplastic left heart syndrome

BACKGROUND

The Single Ventricle Reconstruction trial randomised neonates with hypoplastic left heart syndrome to a systemic-to-pulmonary-artery shunt strategy. Patients received care according to usual institutional practice. We analysed practice variation at the Stage II surgery to attempt to identify areas for decreased variation and process control improvement.

METHODS

Prospectively collected data were available in the Single Ventricle Reconstruction public-use database. Practice variation across 14 centres was described for 397 patients who underwent Stage II surgery. Data are centre-level specific and reported as interquartile ranges across all centres, unless otherwise specified.

RESULTS

Preoperative Stage II median age and weight across centres were 5.4 months (interquartile range 4.9-5.7) and 5.7 kg (5.5-6.1), with 70% performed electively. Most patients had pre-Stage-II cardiac catheterisation (98.5-100%). Digoxin was used by 11/14 centres in 25% of patients (23-31%), and 81% had some oral feeds (68-84%). The majority of the centres (86%) performed a bidirectional Glenn versus hemi-Fontan. Median cardiopulmonary bypass time was 96 minutes (75-113). In aggregate, 26% of patients had deep hypothermic circulatory arrest >10 minutes. In 13/14 centres using deep hypothermic circulatory arrest, 12.5% of patients exceeded 10 minutes (8-32%). Seven centres extubated 5% of patients (2-40) in the operating room. Postoperatively, ICU length of stay was 4.8 days (4.0-5.3) and total length of stay was 7.5 days (6-10).

CONCLUSIONS

In the Single Ventricle Reconstruction Trial, practice varied widely among centres for nearly all perioperative factors surrounding Stage II. Further analysis may facilitate establishing best practices by identifying the impact of practice variation.