An empirically based tool for analyzing morbidity associated with operations for congenital heart disease

OBJECTIVE

Congenital heart surgery outcomes analysis requires reliable methods of estimating the risk of adverse outcomes. Contemporary methods focus primarily on mortality or rely on expert opinion to estimate morbidity associated with different procedures. We created an objective, empirically based index that reflects statistically estimated risk of morbidity by procedure.

METHODS

Morbidity risk was estimated using data from 62,851 operations in the Society of Thoracic Surgeons Congenital Heart Surgery Database (2002-2008). Model-based estimates with 95% Bayesian credible intervals were calculated for each procedure's average risk of major complications and average postoperative length of stay. These 2 measures were combined into a composite morbidity score. A total of 140 procedures were assigned scores ranging from 0.1 to 5.0 and sorted into 5 relatively homogeneous categories.

RESULTS

Model-estimated risk of major complications ranged from 1.0% for simple procedures to 38.2% for truncus arteriosus with interrupted aortic arch repair. Procedure-specific estimates of average postoperative length of stay ranged from 2.9 days for simple procedures to 42.6 days for a combined atrial switch and Rastelli operation. Spearman rank correlation between raw rates of major complication and average postoperative length of stay was 0.82 in procedures with n greater than 200. Rate of major complications ranged from 3.2% in category 1 to 30.0% in category 5. Aggregate average postoperative length of stay ranged from 6.3 days in category 1 to 34.0 days in category 5.

CONCLUSIONS

Complication rates and postoperative length of stay provide related but not redundant information about morbidity. The Morbidity Scores and Categories provide an objective assessment of risk associated with operations for congenital heart disease, which should facilitate comparison of outcomes across cohorts with differing case mixes.

Long-term functional health status and exercise test variables for patients with pulmonary atresia with intact ventricular septum: a Congenital Heart Surgeons Society study

BACKGROUND

A bias favoring biventricular (BV) repair exists regarding choice of repair pathway for patients with pulmonary atresia with intact ventricular septum (PAIVS). We sought to determine the implications of moving borderline candidates down a BV route in terms of late functional health status (FHS) and exercise capacity (EC).

METHODS

Between 1987 and 1997, 448 neonates with PAIVS were enrolled in a multi-institutional study. Late EC and FHS were assessed following repair (mean 14 years) using standardized exercise testing and 3 validated FHS instruments. Relationships between FHS, EC, morphology, and 3 end states (ie, BV, univentricular [UV], or 1.5-ventricle repair [1.5V]) were evaluated.

RESULTS

One hundred two of 271 end state survivors participated (63 BV, 25 UV, and 14 1.5V). Participants had lower FHS scores in domains of physical functioning (P < .001) compared with age- and sex-matched normal controls, but scored significantly higher in nearly all psychosocial domains. EC was higher in 1.5V-repair patients (P = .02), whereas discrete FHS measures were higher in BV-repair patients. Peak oxygen consumption was low across all groups, and was positively correlated with larger initial tricuspid valve z-score (P < .001), with an enhanced effect within the BV-repair group.

CONCLUSIONS

Late patient-perceived physical FHS and measured EC are reduced, regardless of PAIVS repair pathway, with an important dichotomy whereby patients with PAIVS believe they are doing well despite important physical impediments. For those with smaller initial tricuspid valve z-score, achievement of survival with BV repair may be at a cost of late deficits in exercise capacity, emphasizing that better outcomes may be achieved for borderline patients with a 1.5V- or UV-repair strategy.

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.

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.

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.

Trends in endocarditis hospitalizations at US children's hospitals: impact of the 2007 American Heart Association Antibiotic Prophylaxis Guidelines

BACKGROUND

In 2007, the American Heart Association recommended cessation of antibiotic prophylaxis for infective endocarditis (IE) before dental procedures for all but those at highest risk for adverse outcomes from IE. The impact of these guidelines is unclear. We evaluated IE hospitalizations at US children's hospitals during this period.

METHODS

Children <18 years old hospitalized from 2003 to 2010 with IE at 37 centers in the Pediatric Health Information Systems Database were included. Using Poisson regression, we evaluated the number IE hospitalizations over time (raw and indexed to total hospital admissions).

RESULTS

A total of 1157 IE cases were identified; 68% had congenital heart disease (CHD). The raw number of IE cases did not change significantly over time (+1.6% difference post vs pre guidelines, 95% CI -6.4% to +10.3%, P = .7). When the number of IE cases was indexed per 1,000 hospital admissions, there was a significant decline during the time period before the guidelines (annual change: -5.9%, 95% CI -9.9 to -1.8, P = .005) and a similar decline in the post guidelines period such that the difference between the 2 periods was not significant (P = .15). In subgroup analysis, no significant change over time in IE cases (raw or indexed) was found in the CHD subset, those 5 to 18 years old (subgroup most likely receiving dental care), or in cases coded as oral streptococci.

CONCLUSIONS

We found no evidence that release of new antibiotic prophylaxis guidelines was associated with a significant change in IE admissions across 37 US children's hospitals.

Perioperative methylprednisolone and outcome in neonates undergoing heart surgery

BACKGROUND

Recent studies have called into question the benefit of perioperative corticosteroids in children undergoing heart surgery, but have been limited by the lack of placebo control, limited power, and grouping of various steroid regimens together in analysis. We evaluated outcomes across methylprednisolone regimens versus no steroids in a large cohort of neonates.

METHODS

Clinical data from the Society of Thoracic Surgeons Database were linked to medication data from the Pediatric Health Information Systems Database for neonates (≤30 days) undergoing heart surgery (2004-2008) at 25 participating centers. Multivariable analysis adjusting for patient and center characteristics, surgical risk category, and within-center clustering was used to evaluate the association of methylprednisolone regimen with outcome.

RESULTS

A total of 3180 neonates were included: 22% received methylprednisolone on both the day before and day of surgery, 12% on the day before surgery only, and 28% on the day of surgery only; 38% did not receive any perioperative steroids. In multivariable analysis, there was no significant mortality or length-of-stay benefit associated with any methylprednisolone regimen versus no steroids, and no difference in postoperative infection. In subgroup analysis by surgical-risk group, there was a significant association of methylprednisolone with infection consistent across all regimens (overall odds ratio 2.6, 95% confidence interval 1.3-5.2) in the lower-surgical-risk group.

CONCLUSIONS

This multicenter observational analysis did not find any benefit associated with methylprednisolone in neonates undergoing heart surgery and suggested increased infection in certain subgroups. These data reinforce the need for a large randomized trial in this population.

Association of center volume with mortality and complications in pediatric heart surgery

OBJECTIVE

Previous analyses have suggested center volume is associated with outcome in children undergoing heart surgery. However, data are limited regarding potential mediating factors, including the relationship of center volume with postoperative complications and mortality in those who suffer a complication. We examined this association in a large multicenter cohort.

METHODS

Children 0 to 18 years undergoing heart surgery at centers participating in the Society of Thoracic Surgeons Congenital Heart Surgery Database (2006-2009) were included. In multivariable analysis, we evaluated outcomes associated with annual center volume, adjusting for patient factors and surgical risk category.

RESULTS

A total of 35 776 patients (68 centers) were included. Overall, 40.6% of patients had ≥1 complication, and the in-hospital mortality rate was 3.9%. The mortality rate in those patients with a complication was 9.0%. In multivariable analysis, lower center volume was significantly associated with higher in-hospital mortality. There was no association of center volume with the rate of postoperative complications, but lower center volume was significantly associated with higher mortality in those with a complication (P = .03 when volume examined as a continuous variable; odds ratio in centers with <150 vs >350 cases per year = 1.59 [95% confidence interval: 1.16-2.18]). This association was most prominent in the higher surgical risk categories.

CONCLUSIONS

These data suggest that the higher mortality observed at lower volume centers in children undergoing heart surgery may be related to a higher rate of mortality in those with postoperative complications, rather than a higher rate of complications alone.

Comparative analysis of antifibrinolytic medications in pediatric heart surgery

OBJECTIVES

Recent studies suggest adverse events associated with aprotinin in adults may not occur in children, and there is interest in further pediatric study of aprotinin. However, there are limited contemporary data comparing aprotinin with other available antifibrinolytics (aminocaproic acid [ACA] and tranexamic acid [TXA]) to guide current practice and aid in potential trial design. We performed a comparative analysis in a large multicenter cohort.

METHODS

The Society of Thoracic Surgeons Congenital Heart Surgery Database (2004-2008) was linked to medication data from the Pediatric Health Information Systems Database. Efficacy and safety outcomes were evaluated in multivariable analysis adjusting for patient and center factors overall and in neonates and those undergoing redo sternotomy.

RESULTS

A total of 22,258 patients (25 centers) were included: median age, 7.6 months (interquartile range, 2.6-43.4 months). Aprotinin (vs no drug) was associated with a significant reduction in combined hospital mortality/bleeding requiring surgical intervention overall (odds ratio [OR], 0.81; 95% confidence intervals [CI], 0.68-0.91) and in the redo sternotomy subgroup (OR, 0.57; 95% CI, 0.40-0.80). There was no benefit in neonates and no difference in renal failure requiring dialysis in any group. In comparative analysis, there was no difference in outcome in aprotinin versus ACA recipients. TXA (vs aprotinin) was associated with significantly reduced mortality/bleeding requiring surgical intervention overall (OR, 0.47; 95% CI, 0.30-0.74) and in neonates (OR, 0.30; 95% CI, 0.15-0.58).

CONCLUSIONS

These observational data suggest aprotinin is associated with reduced bleeding and mortality in children undergoing heart surgery with no increase in dialysis. Comparative analyses suggest similar efficacy of ACA and improved outcomes associated with TXA.

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.

Outcomes of repair of common arterial trunk with truncal valve surgery: a review of the society of thoracic surgeons congenital heart surgery database

BACKGROUND

Previous studies have suggested truncal valve insufficiency may adversely affect outcome after common arterial trunk (CAT) repair. It is unknown if truncal insufficiency requiring truncal valve surgery (TVS) at the time of primary CAT repair impacts outcome.

METHODS

Patients in The Society of Thoracic Surgeons Congenital Heart Surgery Database undergoing CAT repair from 2000 to 2009 were included. Outcomes were compared for patients with and without TVS at the time of CAT repair and were further stratified by interrupted aortic arch (IAA) repair.

RESULTS

Of 572 patients (63 centers), median age at surgery was 12 days (interquartile range, 6 to 34). Twenty-three patients underwent concomitant TVS (n=22 repair, n=1 replacement) during CAT repair, and 4 patients underwent TVS later during the same hospitalization (n=1 repair, n=3 replacement). Thirty-nine patients underwent IAA repair at the time of CAT repair, 5 of whom had concomitant TVS. Mortality for CAT repair with TVS versus isolated CAT repair was 30% versus 10% (p=0.0002). All 4 patients who required TVS later during the admission died. Truncal valve surgery was associated with increased mortality among CAT patients both with and without IAA repair, with the highest mortality (60%) among CAT patients undergoing IAA repair and TVS (n=5). Common arterial trunk plus TVS had an increased risk of mechanical support and a longer hospital stay.

CONCLUSIONS

Truncal valve surgery in patients undergoing CAT repair is associated with significant mortality. Repair of IAA and TVS at the time of CAT repair carries particularly high risk. Failure to address significant truncal insufficiency, necessitating early reoperation with TVS, had uniformly poor outcomes.

The complex relationship between center volume and outcome in patients undergoing the Norwood operation

BACKGROUND

Norwood outcomes vary across centers, and a relationship between center volume and outcome has been previously described. It is unclear whether this volume-outcome relationship exists across all levels of patient risk or holds true for all centers. We evaluated the impact of patient risk status on the relationship between center volume and outcome, and the extent to which differences in center volume account for between-center variation in outcome.

METHODS

Infants in The Society of Thoracic Surgeons Congenital Heart Surgery Database undergoing the Norwood operation (2000 to 2009) were included. Mortality associated with annual Norwood volume overall and across patient preoperative risk tertiles was evaluated in multivariable analysis. We also estimated the proportion of between-center variation in mortality explained by center volume.

RESULTS

The cohort included 2,557 infants from 53 centers: 34 centers with 0 to 10 Norwood cases per year; 13 centers with 11 to 20 cases per year; and 6 centers with more than 20 cases per year. Unadjusted in-hospital mortality was 22%. In multivariable analysis, lower center volume was associated with higher mortality (odds ratio in low-volume versus high-volume centers 1.54, 95% confidence interval: 1.02 to 2.32, p=0.04). The volume-outcome relationship did not differ across preoperative risk tertiles (p=0.7). Norwood volume explained an estimated 14% of the between-center variation in mortality observed, and significant between-center variation in mortality remained after adjusting for volume (p<0.001).

CONCLUSIONS

Center volume is modestly associated with outcome after the Norwood operation independent of patient risk status. However, this relationship explains only a portion of the between-center variation in mortality in this cohort.

Complications after the Norwood operation: an analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database

BACKGROUND

Limited multicenter data exist regarding the prevalence of postoperative complications after the Norwood operation and their associated mortality risk.

METHODS

We evaluated infants in The Society of Thoracic Surgeons Congenital Heart Surgery Database who underwent the Norwood operation from 2000 to 2009. The prevalence of postoperative complications after the Norwood operation and associated in-hospital mortality were described. Patient factors associated with complications were evaluated in multivariable analyses.

RESULTS

A total of 2,557 patients from 53 centers were included. Median age at operation was 6 days (interquartile range, 4 to 9 days) and 90% had a right dominant ventricle. Overall mortality was 22%, and 75% had 1 complication or more. Mortality increased with increasing number of complications: 1 complication, 17%; 2 complications, 21%; 3 complications, 26%; 4 complications, 33%; and 5 or more complications, 45%. Renal and cardiovascular complications carried the greatest mortality risk. Patient factors associated with 1 complication or more included weight less than 2.5 kg (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.2 to 2.1), single right versus single left ventricle (OR, 1.4; 95% CI, 1.01 to 2.0), preoperative shock (OR, 1.5; 95% CI, 1.1 to 2.1), non-cardiac/genetic abnormality (OR, 1.5; 95% CI, 1.2 to 1.9), and preoperative mechanical ventilatory (OR, 1.3; 95% CI, 1.03 to 1.6) or circulatory (OR 4.0; 95%CI, 1.6 to 10.2) support.

CONCLUSIONS

Complications after the Norwood operation are common, carry significant mortality risk, and are associated with several preoperative patient characteristics. These data may aid in providing prognostic information to families and in guiding quality improvement initiatives.

Center variation in patient age and weight at Fontan operation and impact on postoperative outcomes

BACKGROUND

The impact of age and weight on outcomes after the Fontan operation is unclear. Previous analyses have suggested that lower weight-for-age z-score is an important predictor of poor outcome in patients undergoing bidirectional Glenn. We evaluated variation in age, weight, and weight-for-age z-score at Fontan across institutions, and the impact of these variables on postoperative morbidity and mortality.

METHODS

Patients in The Society of Thoracic Surgeons Congenital Heart Surgery Database undergoing the Fontan operation (2000 to 2009) were included. Center variation in age, weight, and weight-for-age z-score were described. Multivariable analysis was performed to evaluate the impact of age, weight, and weight-for-age z-score on in-hospital mortality, Fontan failure (combined in-hospital mortality and Fontan takedown/revision), postoperative length of stay, and complications, adjusting for other patient and center factors.

RESULTS

A total of 2,747 patients (68 centers) were included: 61% male; 45% right dominant lesions (38% left dominant, 17% undifferentiated). An extracardiac conduit Fontan (versus lateral tunnel) was performed in 63%; 65% were fenestrated. Median age, median weight at Fontan operation, and proportion with weight-for-age z-score less than -2 varied across centers and ranged from 1.7 to 4.8 years, 10.5 to 16.1 kg, and 0% to 30%, respectively. In multivariable analysis, age and weight were not significantly associated with outcome. Weight-for-age z-score less than -2 was associated with increased in-hospital mortality (odds ratio 2.73, 95% confidence interval: 1.09 to 6.86), Fontan failure (odds ratio 2.59, 95% confidence interval: 1.24 to 5.40), and longer length of stay (+1.2 days, 95% confidence interval: 0.1 to 2.4).

CONCLUSIONS

Weight-for-age z-score less than -2 is associated with significant morbidity and mortality after the Fontan operation independent of other patient and center characteristics.

Care models and associated outcomes in congenital heart surgery

OBJECTIVE

Recently, there has been a shift toward care of children undergoing heart surgery in dedicated pediatric cardiac intensive care units (CICU). The impact of this trend on patient outcomes is unclear. We evaluated postoperative outcomes associated with a CICU versus other ICU models.

PATIENTS AND METHODS

Society of Thoracic Surgeons Congenital Heart Surgery Database participants (2007-2009) who completed an ICU survey were included. In multivariable analysis, we evaluated outcomes associated with a CICU versus other ICUs, adjusting for center volume, patient factors, and Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery surgical risk category.

RESULTS

A total of 20 922 patients (47 centers; 25 with a CICU) were included. Overall unadjusted mortality was 3.8%, median length of stay was 6 days (interquartile range: 4-13), and 21% had 1 or more complications. In multivariable analysis, there was no difference in mortality comparing CICUs versus other ICUs (odds ratio: 0.88 [95% confidence interval: 0.65-1.19]). In stratified analysis, CICUs were associated with lower mortality only among those in Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery category 3 (odds ratio: 0.47 [95% confidence interval: 0.25-0.86]), primarily related to atrioventricular canal repair and arterial switch operation. There was no difference in length of stay or complications overall or in stratified analysis.

CONCLUSIONS

We were not able to detect a difference in postoperative morbidity or mortality associated with the presence of a dedicated CICU for children undergoing heart surgery. There may be a survival benefit in certain subgroups .

Center variation in hospital costs for patients undergoing congenital heart surgery

BACKGROUND

Congenital heart disease consumes significant health care resources; however, there are limited data regarding factors affecting resource utilization. The purpose of this study was to evaluate variation between centers in total hospital costs for 4 congenital heart operations of varying complexity and associated factors.

METHODS AND RESULTS

The Premier Database was used to evaluate total cost in children undergoing isolated atrial septal defect (ASD) repair, ventricular septal defect (VSD) repair, tetralogy of Fallot (TOF) repair, or arterial switch operation (ASO) from 2001 to 2007. Mixed models were used to evaluate the impact of center on total hospital costs adjusting for patient and center characteristics and length of stay. A total of 2124 patients were included: 719 ASD (19 centers), 792 VSD (20 centers), 420 TOF (17 centers), and 193 ASO (13 centers). Total cost increased with complexity of operation from median $12 761 (ASD repair) to $55 430 (ASO). In multivariable analysis, models that accounted for center effects versus those that did not performed significantly better for all 4 surgeries (all P≤0.01). The proportion of total cost variation explained by center was 19% (ASD repair), 11% (VSD repair), 6% (TOF repair), and 3% (ASO). Higher-volume centers had significantly lower hospital costs for ASD and VSD repair but not for TOF repair and ASO.

CONCLUSIONS

Total hospital costs varied significantly by center for all congenital heart surgeries evaluated, even after adjustment for patient and center characteristics and length of stay. Differences among centers were most prominent for lower complexity procedures.

Heterotaxy: lessons learned about patterns of practice and outcomes from the congenital heart surgery database of the society of thoracic surgeons

According to The International Society for Nomenclature of Pediatric and Congenital Heart Disease (ISNPCHD), "Heterotaxy is synonymous with 'visceral heterotaxy' and 'heterotaxy syndrome'. Heterotaxy is defined as an abnormality where the internal thoraco-abdominal organs demonstrate abnormal arrangement across the left-right axis of the body. By convention, heterotaxy does not include patients with either the expected usual or normal arrangement of the internal organs along the left-right axis, also known as 'situs solitus', or patients with complete mirror-imaged arrangement of the internal organs along the left-right axis also known as `situs inversus'." or patients with complete mirror-image arrangement of the internal organs along the left-right axis, also known as situs inversus. The purpose of this article is to review the data about heterotaxy in the Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database. The investigators examined all index operations in the STS Congenital Heart Surgery Database over 12 years from January 1, 1998 to December 31, 2009, inclusive. This analysis resulted in a cohort of 77 153 total index operations. Of these, 1505 operations (1.95%) were performed in patients with heterotaxy. Of the 1505 index operations performed in patients with heterotaxy, 1144 were in patients with asplenia and 361 were in patients with polysplenia. In every STS -EACTS Congenital Heart Surgery Mortality Category, discharge mortality is higher in patients with heterotaxy compared with patients without heterotaxy (EACTS = European Association for Cardio-Thoracic Surgery). Discharge mortality after systemic to pulmonary artery shunt is 6.6% in a cohort of all single-ventricle patients except those with heterotaxy, whereas it is 10.8% in single-ventricle patients with heterotaxy. Discharge mortality after Fontan is 1.8% in a cohort of all single-ventricle patients except those with heterotaxy, whereas it is 4.2% in single-ventricle patients with heterotaxy. The STS Congenital Heart Surgery Database is largest congenital heart surgery database in North America. This review of data from the STS Congenital Heart Surgery Database allows for unique documentation of practice patterns and outcomes. From this analysis, it is clear that heterotaxy is a challenging problem with increased discharge mortality in most subgroups.

Celiac artery flow pattern in infants with single right ventricle following the Norwood procedure with a modified Blalock-Taussig or right ventricle to pulmonary artery shunt

A potential advantage of the right ventricle to pulmonary artery versus modified Blalock-Taussig shunt in patients undergoing the Norwood procedure is limitation of diastolic runoff from the systemic to pulmonary circulation. We evaluated mesenteric flow patterns and gastrointestinal outcomes following the Norwood procedure associated with either shunt type. Patients randomized to a right ventricle to pulmonary artery versus modified Blalock-Taussig shunt in the Pediatric Heart Network Single Ventricle Reconstruction Trial at centers participating in this ancillary study were eligible for inclusion; those with active necrotizing enterocolitis, sepsis, or end-organ dysfunction were excluded. Celiac artery flow characteristics and gastrointestinal outcomes were collected at discharge. Forty-four patients (five centers) were included. Median age at surgery was 5 days [interquartile range (IQR) = 4-8 days]. Median celiac artery resistive index (an indicator of resistance to perfusion) was higher in the modified Blalock-Taussig shunt group (n = 19) versus the right ventricle to pulmonary artery shunt group (n = 25) [1.00 (IQR = 0.84-1.14) vs. 0.82 (IQR = 0.74-1.00), p = 0.02]. There was no difference in interstage weight gain, necrotizing enterocolitis, or feeding intolerance episodes between the groups. The celiac artery resistive index was higher in patients with the modified Blalock-Taussig shunt versus the right ventricle to pulmonary artery shunt but was not associated with measured gastrointestinal outcomes.