Variation in outcomes for benchmark operations: an analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

Complexity stratification of the arterial switch operation: a second learning curve

The arterial switch operation has become a safe operation in many centres. The complexity of the procedure has evolved over the last two decades. Several anatomical features can hardly be considered complex today, namely, normal coronary anatomy, circumflex coming off the right coronary artery, eccentric ostium, and early take-off of an infundibular artery. In addition, as peri-operative mortality becomes very low, the outcomes need to be evaluated on the peri-operative morbidity, late reoperations, and late deaths. The arterial switch operation remains complex in around 20% of the cases, where one or several complexity factors are associated. The complexity of the coronary arteries is a major factor. According to a classification essentially based on the course of the coronary arteries, complex coronaries include: double-looping coronaries, anterior-looping coronaries, intramural coronaries, and single coronary ostium. The most challenging coronary pattern remains the association of a single ostium with intramural course. Other features are equally complex: severe malalignment of the commissures, aortic arch obstruction, multiple ventricular septal defect, Taussig-Bing with subaortic obstruction, double-outlet right ventricle non-committed ventricular septal defect, transposition of the great arteries-intact ventricular septum >3 weeks, transposition of the great arteries-ventricular septal defect with high lung resistances and weight <2.5 kg. Owing to the fact that the risks of arterial switch operation vary according to the experience of the centres, we defined the arterial switch operation complexity based on a subjective approach as proposed by the Aristotle comprehensive score. The recent introduction of a morbidity score will allow to stratify more accurately the outcomes when the peri-operative mortality is very low or nil. The complexity of the coronary patterns tends to be well controlled today. It remains that rare coronary failures and aortic root dilation will occur in the long term, requiring a close follow-up of the most complex patients. Successfully achieving complex arterial switch operation implies a second learning curve.

Long-term management of adults with conotruncal lesions: the diagnostic approach at All Children's Hospital

Improved survival in children with complex congenital cardiac disease, such as conotruncal abnormalities, has created a sub-population of children and young adults who need comprehensive multi-disciplinary long-term follow-up. Routine surveillance with comprehensive screening for structural heart disease, functional heart disease, thromboembolic disease, arrhythmias, and associated end-organ dysfunction is important. Future research will better define the care plans for routine surveillance in patients with conotruncal abnormalities.

Centre variation in cost and outcomes for congenital heart surgery

Although overall outcomes for children undergoing heart surgery have improved, there is a significant variation in outcomes across hospitals. This review discusses the variation in cost and outcomes across centres performing congenital heart surgery, potential underlying mechanisms, and efforts to reduce variation and improve outcome.

Differential case ascertainment in clinical registry versus administrative data and impact on outcomes assessment for pediatric cardiac operations

BACKGROUND

Administrative datasets are often used to assess outcomes and quality of pediatric cardiac programs; however their accuracy regarding case ascertainment is unclear. We linked patient data (2004-2010) from the Society of Thoracic Surgeons Congenital Heart Surgery (STS-CHS) Database (clinical registry) and the Pediatric Health Information Systems (PHIS) database (administrative database) from hospitals participating in both to evaluate differential coding/classification of operations between datasets and subsequent impact on outcomes assessment.

METHODS

Eight individual benchmark operations and the Risk Adjustment in Congenital Heart Surgery, version 1 (RACHS-1) categories were evaluated. The primary outcome was in-hospital mortality.

RESULTS

The cohort included 59,820 patients from 33 centers. There was a greater than 10% difference in the number of cases identified between data sources for half of the benchmark operations. The negative predictive value (NPV) of the administrative (versus clinical) data was high (98.8%-99.9%); the positive predictive value (PPV) was lower (56.7%-88.0%). Overall agreement between data sources in RACHS-1 category assignment was 68.4%. These differences translated into significant differences in outcomes assessment, ranging from an underestimation of mortality associated with truncus arteriosus repair by 25.7% in the administrative versus clinical data (7.01% versus 9.43%; p = 0.001) to an overestimation of mortality associated with ventricular septal defect (VSD) repair by 31.0% (0.78% versus 0.60%; p = 0.1). For the RACHS-1 categories, these ranged from an underestimation of category 5 mortality by 40.5% to an overestimation of category 2 mortality by 12.1%; these differences were not statistically significant.

CONCLUSIONS

This study demonstrates differences in case ascertainment between administrative and clinical registry data for children undergoing cardiac operations, which translated into important differences in outcomes assessment.

Initial application in the EACTS and STS Congenital Heart Surgery Databases of an empirically derived methodology of complexity adjustment to evaluate surgical case mix and results

OBJECTIVES

Outcomes evaluation is enhanced by assignment of operative procedures to appropriate categories based upon relative average risk. Formal risk modelling is challenging when a large number of operation types exist, including relatively rare procedures. Complexity stratification provides an alternative methodology. We report the initial application in the Congenital Heart Surgery Databases of the Society of Thoracic Surgeons (STS) and the European Association for Cardio-thoracic Surgery (EACTS) of an empirically derived system of complexity adjustment to evaluate surgical case mix and results.

METHODS

Complexity stratification is a method of analysis in which the data are divided into relatively homogeneous groups (called strata). A complexity stratification tool named the STS-EACTS Congenital Heart Surgery Mortality Categories (STAT Mortality Categories) was previously developed based on the analysis of 77,294 operations entered in the Congenital Heart Surgery Databases of EACTS (33,360 operations) and STS (43,934 patients). Procedure-specific mortality rate estimates were calculated using a Bayesian model that adjusted for small denominators. Operations were sorted by increasing risk and grouped into five categories (the STAT Mortality Categories) that were designed to minimize within-category variation and maximize between-category variation. We report here the initial application of this methodology in the EACTS Congenital Heart Surgery Database (47,187 operations performed over 4 years: 2006-09) and the STS Congenital Heart Surgery Database (64,307 operations performed over 4 years: 2006-09).

RESULTS

In the STS Congenital Heart Surgery Database, operations classified as STAT Mortality Categories 1-5 were (1): 17332, (2): 20114, (3): 9494, (4): 14525 and (5): 2842. Discharge mortality was (1): 0.54%, (2): 1.6%, (3): 2.4%, (4): 7.5% and (5): 17.8%. In the EACTS Congenital Heart Surgery Database, operations classified as STAT Mortality Categories 1-5 were (1): 19874, (2): 12196, (3): 5614, (4): 8287 and (5): 1216. Discharge mortality was (1): 0.99%, (2): 2.9%, (3): 5.0%, (4): 10.3% and (5): 25.0%.

CONCLUSIONS

The STAT Mortality Categories facilitate analysis of outcomes across the wide spectrum of distinct congenital heart surgery operations including infrequently performed procedures.

Status of the pediatric clinical trials enterprise: an analysis of the US ClinicalTrials.gov registry

BACKGROUND AND OBJECTIVES

Clinical trials are the gold standard for generating evidence-based knowledge in medicine. Recent legislation requiring trials to be registered at ClinicalTrials.gov has enabled evaluation of the clinical trial enterprise as a whole, which was previously not possible. The purpose of this study was to create a snapshot of the pediatric clinical trial portfolio.

METHODS

All interventional trials registered at ClinicalTrials.gov from July 2005 to September 2010 were included. Pediatric (ie, enrolling patients aged 0-18 years) trial characteristics, therapeutic area, location, and funding were described. Secondary objectives included describing pediatric trials over time and comparison with nonpediatric trials.

RESULTS

During this time, 5035 pediatric trials were registered compared with >10 times as many nonpediatric trials. Neonates/infants were eligible for enrollment in 46.6% of trials versus children (77.9%) and adolescents (45.2%). Nearly one-half of pediatric trials enrolled <100 subjects, and more pediatric trials versus nonpediatric trials evaluated preventive therapies. The proportion of pediatric trials evaluating a drug intervention declined over time, and there were fewer Phase 0 to II versus Phase III to IV trials. Infectious disease/vaccine studies (23%) were the most common, followed by psychiatric/mental health (13%) studies. Many trials enrolled patients outside the United States, and <15% of trials were sponsored by the National Institutes of Health or other US federal agencies.

CONCLUSIONS

Analysis of the ClinicalTrials.gov data set allows description of the current scope of pediatric trials. These data may be useful to stakeholders in informing decisions regarding the conduct of trials in children and provide insight into mechanisms to advance pediatric trial infrastructure and methodology toward improving child health.

Tetralogy of fallot: a surgical perspective

Tetralogy of Fallot (TOF) is an index lesion for all paediatric and congenital heart surgeons. In designing an appropriate operation for children with TOF, the predicted postoperative physiology must be taken into account, both for the short and long term. A favourable balance between pulmonary stenosis (PS) and pulmonary insufficiency (PI) may be critical for preservation of biventricular function. A unified repair strategy to limit both residual PS and PI is presented, along with supportive experimental evidence. A strategy for dealing with coronary anomalies and some comments regarding best timing of operation are also included.

Effect of sex and race on outcome in patients undergoing congenital heart surgery: an analysis of the society of thoracic surgeons congenital heart surgery database

BACKGROUND

Previous studies on the impact of race and sex on outcome in children undergoing cardiac operations were based on analyses of administrative claims data. This study uses clinical registry data to examine potential associations of sex and race with outcomes in congenital cardiac operations, including in-hospital mortality, postoperative length of stay (LOS), and complications.

METHODS

The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) was queried for patients younger than 18 years undergoing cardiac operations from 2007 to 2009. Preoperative, operative, and outcome data were collected on 20,399 patients from 49 centers. In multivariable analysis, the association of race and sex with outcome was examined, adjusting for patient characteristics, operative risk (Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery [STAT] mortality category), and operating center.

RESULTS

Median age at operation was 0.4 years (interquartile range 0.1-3.4 years), and 54.4% of patients were boys. Race/ethnicity included 54.9% white, 17.1% black, 16.4% Hispanic, and 11.7% "other." In adjusted analysis, black patients had significantly higher in-hospital mortality (odds ratio [OR], 1.67; 95% confidence interval [CI], 1.37-2.04; p<0.001) and complication rate (OR, 1.15; 95% CI, 1.04-1.26; p<0.01) in comparison with white patients. There was no significant difference in mortality or complications by sex. Girls had a shorter LOS than boys (-0.8 days; p<0.001), whereas black (+2.4 days; p<0.001) and Hispanic patients (0.9 days; p<0.01) had longer a LOS compared with white patients.

CONCLUSIONS

These data suggest that black children have higher mortality, a longer LOS, and an increased complication rate. Girls had outcomes similar to those of boys but with a shorter LOS of almost a day. Further study of potential causes underlying these race and sex differences is warranted.

Changing expectations for neurological outcomes after the neonatal arterial switch operation

BACKGROUND

Expectations for outcomes after the neonatal arterial switch operation (ASO) continue to change. This cohort study describes neurodevelopmental outcomes at age 12 months after neonatal ASO, and analyzes both modifiable and nonmodifiable factors for association with adverse outcomes.

METHODS

Patients who underwent an ASO (n=30) were enrolled in a prospective outcome study, with comprehensive clinical data collection during the first 12 months of life. Brain magnetic resonance imaging was done preoperatively and 7 days postoperatively, and the Bayley Scales of Infant Development III was performed at age 12 months.

RESULTS

Ten of 30 patients (33%) had preoperative magnetic resonance imaging injury; 13 of 30 patients (43%) had new postoperative magnetic resonance imaging injury. Twenty patients (67%) had Bayley Scales of Infant Development III: Cognitive Composite standard score mean was 104.8±15.0, Language Composite standard score median was 90.0 (25th to 75th percentile, 83 to 94), and Motor Composite standard score mean was 92.3±14.2. Best subsets multivariable analysis found associations between lower preoperative and intraoperative cerebral oxygen saturation, preoperative magnetic resonance imaging brain injury, total bypass time, and total midazolam dose and lower Bayley Scales of Infant Development III scores at age 12 months.

CONCLUSIONS

At 12 months after ASO, neurodevelopmental outcome means were within normal population ranges. The new associations reported in this study between potentially modifiable perioperative factors and outcomes require investigations in larger patient cohorts. Beyond survival, which was 100% in this cohort, factors influencing quality of life including neurodevelopmental outcomes should be routinely investigated in studies of ASO patients.

Variation in outcomes for risk-stratified pediatric cardiac surgical operations: an analysis of the STS Congenital Heart Surgery Database

BACKGROUND

We evaluated outcomes for groups of risk-stratified operations in The Society of Thoracic Surgeons Congenital Heart Surgery Database to provide contemporary benchmarks and examine variation between centers.

METHODS

Patients undergoing surgery from 2005 to 2009 were included. Centers with more than 10% missing data were excluded. Discharge mortality and postoperative length of stay (PLOS) among patients discharged alive were calculated for groups of risk-stratified operations using the five Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery mortality categories (STAT Mortality Categories). Power for analyzing between-center differences in outcome was determined for each STAT Mortality Category. Variation was evaluated using funnel plots and Bayesian hierarchical modeling.

RESULTS

In this analysis of risk-stratified operations, 58,506 index operations at 73 centers were included. Overall discharge mortality (interquartile range among programs with more than 10 cases) was as follows: STAT Category 1=0.55% (0% to 1.0%), STAT Category 2=1.7% (1.0% to 2.2%), STAT Category 3=2.6% (1.1% to 4.4%), STAT Category 4=8.0% (6.3% to 11.1%), and STAT Category 5=18.4% (13.9% to 27.9%). Funnel plots with 95% prediction limits revealed the number of centers characterized as outliers by STAT Mortality Categories was as follows: Category 1=3 (4.1%), Category 2=1 (1.4%), Category 3=7 (9.7%), Category 4=13 (17.8%), and Category 5=13 (18.6%). Between-center variation in PLOS was analyzed for all STAT Categories and was greatest for STAT Category 5 operations.

CONCLUSIONS

This analysis documents contemporary benchmarks for risk-stratified pediatric cardiac surgical operations grouped by STAT Mortality Categories and the range of outcomes among centers. Variation was greatest for the more complex operations. These data may aid in the design and planning of quality assessment and quality improvement initiatives.

Variation in perioperative care across centers for infants undergoing the Norwood procedure

OBJECTIVES

In the Single Ventricle Reconstruction trial, infants undergoing the Norwood procedure were randomly allocated to undergo a right ventricle-to-pulmonary artery shunt or a modified Blalock-Taussig shunt. Apart from shunt type, subjects received the local standard of care. We evaluated variation in perioperative care during the Norwood hospitalization across 14 trial sites.

METHODS

Data on preoperative, operative, and postoperative variables for 546 enrolled subjects who underwent the Norwood procedure were collected prospectively on standardized case report forms, and variation across the centers was described.

RESULTS

Gestational age, birth weight, and proportion with hypoplastic left heart syndrome were similar across sites. In contrast, all recorded variables related to preoperative care varied across centers, including fetal diagnosis (range, 55%-85%), preoperative intubation (range, 29%-91%), and enteral feeding. Perioperative and operative factors were also variable across sites, including median total support time (range, 74-189 minutes) and other perfusion variables, arch reconstruction technique, intraoperative medication use, and use of modified ultrafiltration (range, 48%-100%). Additional variation across centers was seen in variables related to postoperative care, including proportion with an open sternum (range, 35%-100%), median intensive care unit stay (range, 9-44 days), type of feeding at discharge, and enrollment in a home monitoring program (range, 1%-100%; 5 sites did not have a program). Overall, in-hospital death or transplant occurred in 18% (range across sites, 7%-39%).

CONCLUSIONS

Perioperative care during the Norwood hospitalization varies across centers. Further analysis evaluating the underlying causes and relationship of this variation to outcome is needed to inform future studies and quality improvement efforts.

Evaluation of failure to rescue as a quality metric in pediatric heart surgery: an analysis of the STS Congenital Heart Surgery Database

BACKGROUND

Failure to rescue (FTR; the probability of death after a complication) has been adopted as a quality metric in adult cardiac surgery, in which it has been shown that high-performing centers with low mortality rates do not have fewer complications, but rather lower mortality in those who experience a complication (lower FTR). It is unknown whether this holds true in pediatric heart surgery. We characterized the relationship between complications, FTR, and mortality in this population.

METHODS

Children (0 to 18 years) undergoing heart surgery at centers participating in the Society of Thoracic Surgeons Congenital Heart Surgery Database (2006 to 2009) were included. Outcomes were examined in multivariable analysis adjusting for patient characteristics, surgical risk category, and within-center clustering.

RESULTS

This study included 40,930 patients from 72 centers. Overall in-hospital mortality was 3.7%, 39.3% had a postoperative complication, and the FTR rate (number of deaths in those with a complication) was 9.1%. When hospitals were characterized by in-hospital mortality rate, there was no difference across hospital mortality tertiles in the complication rate in adjusted analysis; however, hospitals in the lowest mortality tertile had significantly lower FTR rates (6.6% versus 12.4%; p<0.0001). Similar results were seen when evaluating high-severity complications and across surgical risk groups.

CONCLUSIONS

This analysis suggests that hospitals with low mortality rates do not have fewer complications after pediatric heart surgery, but instead have lower mortality in those who experience a complication (lower FTR). Further investigation into FTR as a quality metric in pediatric heart surgery is warranted.

Relative impact of surgeon and center volume on early mortality after the Norwood operation

BACKGROUND

Previous studies suggest center volume is associated with outcome after the Norwood operation; however, the impact of surgeon volume is less clear. We evaluated the relative impact of surgeon and center volume on mortality in a large Norwood cohort.

METHODS

Patients in the Society of Thoracic Surgeons Congenital Heart Surgery Database undergoing the Norwood operation (2000 to 2009) were included. Using multivariable logistic regression, we evaluated the relationship between in-hospital mortality and annual center and surgeon volume, adjusting for patient factors.

RESULTS

A total of 2,555 patients were operated on at 53 centers by 111 surgeons. Overall unadjusted mortality was 22.1%. When analyzed individually, both lower center and surgeon volume were associated with higher mortality (odds ratio for centers with 0 to 10 vs >20 cases per year 1.56 [95% confidence interval 1.05 to 2.31]; odds ratio for surgeons with 0 to 5 vs >10 cases per year 1.60 [95% confidence interval 1.12 to 2.27]). When analyzed together, the addition of surgeon volume to the center volume models attenuated but did not completely mitigate the association of center volume with outcome (relative attenuation of odds ratio=34%). Adjusted mortality rates in low, medium, and high volume centers were 25.6%, 22.3%, and 17.7%, respectively. Across all center volume strata, lower volume surgeons had higher adjusted mortality rates.

CONCLUSIONS

Both center and surgeon volumes appear to influence Norwood outcomes. These data suggest outcomes may potentially be improved through strategies that take advantage of the positive influence of both of these variables. This could include further investigation into the feasibility of regional collaborations, and the development of quality improvement initiatives within and across centers.

Quality measures for congenital and pediatric cardiac surgery

This article presents 21 "Quality Measures for Congenital and Pediatric Cardiac Surgery" that were developed and approved by the Society of Thoracic Surgeons (STS) and endorsed by the Congenital Heart Surgeons' Society (CHSS). These Quality Measures are organized according to Donabedian's Triad of Structure, Process, and Outcome. It is hoped that these quality measures can aid in congenital and pediatric cardiac surgical quality assessment and quality improvement initiatives.

Opportunities and challenges in linking information across databases in pediatric cardiovascular medicine

Multicenter databases are increasingly utilized in pediatric cardiovascular research. In this review, we discuss the rational for using these types of data sources, provide several examples of how large datasets have been utilized in clinical research, and describe different mechanisms for linking databases to enable studies not possible with individual datasets alone.