The importance of patient-specific preoperative factors: an analysis of the society of thoracic surgeons congenital heart surgery database

Comparing apples to apples: Exploring public reporting of congenital cardiac surgery outcomes based on common congenital heart operations

OBJECTIVE

We sought to simplify reporting of outcomes in congenital heart surgery that compares well-defined patient groups and accommodates multiple stakeholder needs while being easily understandable.

METHODS

We selected 19 commonly performed congenital heart surgeries ranging in complexity from repair of atrial septal defects to the Norwood procedure. Strict inclusion/exclusion criteria ensured the creation of 19 well-defined diagnosis/procedure cohorts. Preoperative, procedural, and postoperative data were collected for consecutive eligible patients from 9 centers between January 1, 2016, and December 31, 2021. Unadjusted operative mortality rates and hospital length of stay for each of the 19 diagnosis/procedure cohorts were summarized in aggregate and stratified by each center.

RESULTS

Of 8572 eligible cases included, numbers in the 19 diagnosis/procedure cohorts ranged from 73 for tetralogy of Fallot repair after previous palliation to 1224 for ventricular septal defect (VSD) repair for isolated VSD. In aggregate, the unadjusted mortality ranged from 0% for atrial septal defect repair to 28.4% for hybrid stage I. There was significant heterogeneity in case mix and mortality for different diagnosis/procedure cohorts across centers (eg, arterial switch operation/VSD, n = 7-42, mortality 0%-7.4%; Norwood procedure, n = 16-122, mortality 5.3%-25%).

CONCLUSIONS

Reporting of institutional case volumes and outcomes within well-defined diagnosis/procedure cohorts can enable centers to benchmark outcomes, understand trends in mortality, and direct quality improvement. When made public, this type of report could provide parents with information on institutional volumes and outcomes and allow them to better understand the experience of each program with operations for specific congenital heart defects.

Cardiac Arrest With or Without Need for Extracorporeal Life Support After Congenital Cardiac Surgery

BACKGROUND

Postoperative cardiac arrest (CA) with or without need for extracorporeal cardiopulmonary resuscitation (ECPR) is one of the most significant complications in the early postoperative period after pediatric cardiac operation. The objective of this study was to develop and to validate a predictive model of postoperative CA with or without ECPR.

METHODS

In this retrospective cohort study, we reviewed data from patients who underwent cardiac surgery with cardiopulmonary bypass (CPB) between July 20, 2020, and December 31, 2021. Variables included demographic data, presence of preoperative risk factors, The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery mortality categories, perioperative data, residual lesion score (RLS), and vasoactive-inotropic score (VIS). We used multivariable logistic regression analysis to develop a predictive model.

RESULTS

The incidence of CA with or without ECPR was 4.4% (n = 24/544). Patients who experienced postoperative CA with or without ECPR were younger (age, 130 [54-816.5] days vs 626 [127.5-2497.5] days; P < .050) and required longer CPB (253 [154-332.5] minutes vs 130 [87-186] minutes; P < .010) and cross-clamp (116.5 [75.5-143.5] minutes vs 64 [30-111] minutes; P < .020) times; 37.5% of patients with an outcome had at least 1 preoperative risk factor (vs 16.9%; P < .010). Our multivariable logistic regression determined that the presence of at least 1 preoperative risk factor (P = .005), CPB duration (P = .003), intraoperative residual lesion score (P = .009), and postsurgery vasoactive-inotropic score (P = .010) were predictors of the incidence of CA with or without ECPR.

CONCLUSIONS

We developed a predictive model of postoperative CA with or without ECPR after congenital cardiac operation. Our model performed better than the individual scores and risk factors.

Prognostic utility of a novel risk prediction model of 1-year mortality in patients surviving to discharge after surgery for congenital or acquired heart disease

OBJECTIVE

We sought to develop a novel risk prediction model of 1-year mortality after congenital heart surgery that accounts for clinical, anatomic, echocardiographic, and socioeconomic factors.

METHODS

This was a single-center, retrospective review of consecutive index operations for congenital or acquired heart disease, from January 2011 to January 2021, among patients with known survival status at 1 year after discharge from the index hospitalization. The primary outcome was postdischarge mortality at 1 year. Variables of interest included age, prematurity, noncardiac anomalies or syndromes, the Childhood Opportunity Index, primary procedure, major adverse postoperative complications, and the Residual Lesion Score. Logistic regression was used to develop a weighted risk score for the primary outcome. Internal validation using a bootstrap-resampling approach was performed.

RESULTS

Of 10,412 consecutive operations for congenital or acquired heart disease, 8808 (84.6%) cases met entry criteria, including survival to discharge. There were 190 (2.2%) deaths at 1 year postdischarge. A weighted risk score was formulated on the basis of the variables in the final risk prediction model, which included all aforementioned risk factors of interest. This model had a C-statistic of 0.82 (95% confidence interval, 0.80-0.85). The median risk score was 6 (interquartile range, 4-8) points. Patients were categorized as low (score 0-5), medium (score 6-10), high (score 11-15), or very high (score 16-20) risk. The expected probability of mortality was 0.4% ± 0.2%, 2.0% ± 1.1%, 10.1% ± 5.0%, and 36.6% ± 9.6% for low-risk, medium-risk, high-risk, and very high-risk patients, respectively.

CONCLUSIONS

A risk prediction model of 1-year mortality may guide prognostication and follow-up of patients after discharge after surgery for congenital or acquired heart disease.

Risk factors for long post-operative hospital stays after cardiopulmonary bypass surgery in full-term neonates

BACKGROUND

Long hospital stays for neonates following cardiac surgery can be detrimental to short- and long-term outcomes. Furthermore, it can impact resource allocation within heart centres' daily operations. We aimed to explore multiple clinical variables and complications that can influence and predict the post-operative hospital length of stay.

METHODS

We conducted a retrospective observational review of the full-term neonates (<30 days old) who had cardiac surgery in a tertiary paediatric cardiac surgery centre - assessment of multiple clinical variables and their association with post-operative hospital length of stay.

RESULTS

A total of 273 neonates were screened with a mortality rate of 8%. The survivors (number = 251) were analysed; 83% had at least one complication. The median post-operative hospital length of stay was 19.5 days (interquartile range 10.5, 31.6 days). The median post-operative hospital length of stay was significantly different among patients with complications (21.5 days, 10.5, 34.6 days) versus the no-complication group (14 days, 9.6, 19.5 days), p < 0.01. Among the non-modifiable variables, gastrostomy, tracheostomy, syndromes, and single ventricle physiology are significantly associated with longer post-operative hospital length of stay. Among the modifiable variables, deep vein thrombosis and cardiac arrest were associated with extended post-operative hospital length of stay.

CONCLUSIONS

Complications following cardiac surgery can be associated with longer hospital stay. Some complications are modifiable. Deep vein thrombosis and cardiac arrest are among the complications that were associated with longer hospital stay and offer a direct opportunity for prevention which may be reflected in better outcomes and shorter hospital stay.

Surgical repair of neonatal total anomalous pulmonary venous connection: A single institutional experience with 241 cases

Objective

Challenges persist in surgery for neonatal total anomalous pulmonary venous connection (neoTAPVC), with the high mortality risk not mitigated over time.

Methods

A prospectively collected single-center database containing all neonates with TAPVC undergoing biventricular repair in 2012 to 2020 was retrospectively reviewed. The primary outcome was death or postoperative pulmonary venous obstruction (PPVO). Based on the preoperative admission location in our hospital, patients were classified into those being admitted to cardiac intensive care unit versus neonatal intensive care unit or general pediatric intensive care unit. Access to dedicated presurgical care (DPC) was defined as patients who were preoperatively admitted to the cardiac intensive care unit.

Results

Overall, 241 patients with a median age at surgery of 14 days (interquartile range [IQR], 9-21 days) were included. Anomalous return was supracardiac in 38.6%, cardiac in 26.1%, infracardiac in 28.6%, and mixed in 6.6%. Patients receiving DPC had better survival (96.3% vs 84.3%; P = .0028) and lower incidence of PPVO (15.2% vs 28.6%; P = .011) compared with those without DPC. Patients in the DPC group were less likely to undergo operation within 24 hours on presentation (27.1% vs 40.3%; P = .041), had improved lactate clearance (1.5 [IQR, 1.0-2.2] vs 2.8 [IQR, 1.8-4.1]; P < .001), and had lower incidence of postoperative pulmonary hypertension crisis (2.8% vs 18.7%; P < .001) compared with those in no-DPC group. After matching, no difference in PPVO could be observed in patients undergoing conventional versus sutureless repair (22.6% vs 12.9%; P = .29).

Conclusions

Access to DPC potentially improves outcomes in the neoTAPVC setting; freedom from PPVO were similar using conventional versus sutureless repair.

Risk factors and early outcomes of repeat sternotomy in 1960 adults with congenital heart disease: A 30-year, single-center study

OBJECTIVE

Patients with congenital heart disease (CHD) increasingly live into adulthood, often requiring cardiac reoperation. We aimed to assess the outcomes of adults with CHD (ACHD) undergoing repeat sternotomy at our institution.

METHODS

Review of our institution's cardiac surgery database identified 1960 ACHD patients undergoing repeat median sternotomy from 1993 to 2023. The primary outcome was early mortality, and the secondary outcome was a composite end point of mortality and significant morbidity. Univariable and multivariable logistic regression models were used to determine factors independently associated with outcomes.

RESULTS

Of the 1960 ACHDs patient undergoing repeat sternotomy, 1183 (60.3%) underwent a second, third (n = 506, 25.8%), fourth (n = 168, 8.5%), fifth (n = 70, 3.5%), and sixth sternotomy or greater (n = 33, 1.6%). CHD diagnoses were minor complexity (n = 145, 7.4%), moderate complexity (n = 1380, 70.4%), and major complexity (n = 435, 22.1%). Distribution of procedures included valve (n = 549, 28%), congenital (n = 625, 32%), aortic (n = 104, 5.3%), and major procedural combinations (n = 682, 34.7%). Overall early mortality was 3.1%. Factors independently associated with early mortality were older age at surgery, CHD of major complexity, preoperative renal failure, preoperative ejection fraction, urgent operation, and postoperative blood transfusion. In addition, sternotomy number and bypass time were independently associated with the composite outcome.

CONCLUSIONS

Despite the increase in early mortality with sternotomy number, sternotomy number was not independently associated with early mortality but with increased morbidity. Improvement strategies should target factors leading to urgent operations, early referral, along with operative efficiency including bypass time and blood conservation.

Racial and Ethnic Variation in ECMO Utilization and Outcomes in Pediatric Cardiac ICU Patients

Background

Previous studies have reported racial disparities in extracorporeal membrane oxygenation (ECMO) utilization in pediatric cardiac patients.

Objectives

The objective of this study was to determine if there was racial/ethnic variation in ECMO utilization and, if so, whether mortality was mediated by differences in ECMO utilization.

Methods

This is a multicenter, retrospective cohort study of the Pediatric Cardiac Critical Care Consortium clinical registry. Analyses were stratified by hospitalization type (medical vs surgical). Logistic regression models were adjusted for confounders and evaluated the association between race/ethnicity with ECMO utilization and mortality. Secondary analyses explored interactions between race/ethnicity, insurance, and socioeconomic status with ECMO utilization and mortality.

Results

A total of 50,552 hospitalizations from 34 hospitals were studied. Across all hospitalizations, 2.9% (N = 1,467) included ECMO. In medical and surgical hospitalizations, Black race and Hispanic ethnicity were associated with severity of illness proxies. In medical hospitalizations, race/ethnicity was not associated with the odds of ECMO utilization. Hospitalizations of other race had higher odds of mortality (adjusted odds ratio [aOR]: 1.61; 95% CI: 1.22-2.12; P = 0.001). For surgical hospitalizations, Black (aOR: 1.24; 95% CI: 1.02-1.50; P = 0.03) and other race (aOR: 1.50; 95% CI: 1.17-1.93; P = 0.001) were associated with higher odds of ECMO utilization. Hospitalizations of Hispanic patients had higher odds of mortality (aOR: 1.31; 95% CI: 1.03-1.68; P = 0.03). No significant interactions were demonstrated between race/ethnicity and socioeconomic status indicators with ECMO utilization or mortality.

Conclusions

Black and other races were associated with increased ECMO utilization during surgical hospitalizations. There were racial/ethnic disparities in outcomes not explained by differences in ECMO utilization. Efforts to mitigate these important disparities should include other aspects of care.

Model-driven survival prediction after congenital heart surgery

OBJECTIVES

The objective of the study was to improve postoperative risk assessment in congenital heart surgery by developing a machine-learning model based on readily available peri- and postoperative parameters.

METHODS

Our bicentric retrospective data analysis from January 2014 to December 2019 of established risk parameters for dismal outcome was used to train and test a model to predict postoperative survival within the first 30 days. The Freiburg training data consisted of 780 procedures; the Heidelberg test data comprised 985 procedures. STAT mortality score, age, aortic cross-clamp time and postoperative lactate values over 24 h were considered.

RESULTS

Our model showed an area under the curve (AUC) of 94.86%, specificity of 89.48% and sensitivity of 85.00%, resulting in 3 false negatives and 99 false positives.The STAT mortality score and the aortic cross-clamp time each showed a statistically highly significant impact on postoperative mortality. Interestingly, a child's age was barely statistically significant. Postoperative lactate values indicated an increased mortality risk if they were either constantly at a high level or low during the first 8 h postoperatively with an increase afterwards.When considering parameters available before, at the end of and 24 h after surgery, the predictive power of the complete model achieved the highest AUC. This, compared to the already high predictive power alone (AUC 88.9%) of the STAT mortality score, translates to an error reduction of 53.5%.

CONCLUSIONS

Our model predicts postoperative survival after congenital heart surgery with great accuracy. Compared with preoperative risk assessments, our postoperative risk assessment reduces prediction error by half. Heightened awareness of high-risk patients should improve preventive measures and thus patient safety.

Operative mortality after Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Mortality Category 1 to 3 procedures: Deficiencies and opportunities for quality improvement

OBJECTIVES

We examined cases of operative mortality at a single quaternary academic center for patients undergoing relatively lower-risk (Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Mortality Category 1-3) procedures, as a means of identifying systemic weaknesses and opportunities for quality improvement.

METHODS

A retrospective review of all operative mortality events for patients who underwent a Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Mortality Category 1, 2, or 3 index procedure (2009-2020) at our institution was performed. After a detailed chart review was performed by 2 independent faculty for each case, factors and system deficiencies that contributed to mortality were identified.

RESULTS

A total of 42 mortalities were identified. A total of 37 patients (88%) had at least 1 Society of Thoracic Surgeons-designated risk factor, including prior cardiac operations (48%), extracardiac malformations (43%), and preoperative ventilation (33%). Eight patients (19%) had non-Society of Thoracic Surgeons-designated preoperative patient-level variables considered as at potential risk, including severe ventricular dysfunction, pulmonary hypertension, lung hypoplasia, and undiagnosed severe coronary abnormalities. Four patients (10%) had no identified preoperative risk factors. After detailed chart review, 5 broad categories were identified: patient-related factors (n = 33; 78%), postoperative infection (n = 13; 31%), postoperative residual lesions (n = 7; 17%), Fontan physiology failure (n = 4; 10%), and unexplained left ventricular failure after tetralogy of Fallot repair (n = 3; 7%). A total of 74% of patients had at least 1 preoperative, intraoperative, or postoperative system deficiency. A total of 50% of surgeries were urgent or emergency.

CONCLUSIONS

Operative mortality after Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Mortality Category 1 to 3 procedures is related to the presence of multifactorial risk patterns (Society of Thoracic Surgeons and non-Society of Thoracic Surgeons-designated patient-level risk factors and variables, broad risk categories, system deficiencies, emergency surgery). A multidisciplinary approach to care, with early recognition and treatment of modifiable additional burdens, could reduce this risk.

Age at surgery and outcomes following neonatal cardiac surgery: An analysis from the Pediatric Cardiac Critical Care Consortium

OBJECTIVE

The optimal timing for neonatal cardiac surgery is a potentially modifiable factor that may affect outcomes. We studied the relationship between age at surgery (AAS) and outcomes across multiple hospitals, focusing on neonatal operations where timing appears is not emergency.

METHODS

We studied neonates ≥37 weeks' gestation and ≥2.5 kg admitted to a treating hospital on or before day of life 2 undergoing selected index cardiac operations. The impact of AAS on outcomes was evaluated across the entire cohort and a standard risk subgroup (ie, free of preoperative mechanical ventilation, mechanical circulatory support, or other organ failure). Outcomes included mortality, major morbidity (ie, cardiac arrest, mechanical circulatory support, unplanned cardiac reintervention, or neurologic complication), and postoperative cardiac intensive care unit and hospital length of stay. Post hoc analyses focused on operations undertaken between day of life 2 and 7.

RESULTS

We studied 2536 neonates from 47 hospitals. AAS from day of life 2 through 7 was not associated with risk adjusted mortality or major morbidity among the entire cohort and the standard risk subgroup. Older AAS, although associated with modest increases in postoperative cardiac intensive care unit and hospital length of stay in the entire cohort, was not associated with hospital length of stay in the standard risk subgroup.

CONCLUSIONS

Among select nonemergency neonatal cardiac operations, AAS between day of life 2 and 7 was not found to be associated with risk adjusted mortality or major morbidity. Although delays in surgical timing may modestly increase preoperative resource use, studies of AAS and outcomes not evident at the time of discharge are needed.

Variation in hospital costs and resource utilisation after congenital heart surgery

BACKGROUND

Children undergoing cardiac surgery have overall improving survival, though they consume substantial resources. Nationwide inpatient cost estimates and costs at longitudinal follow-up are lacking.

METHODS

Retrospective cohort study of children <19 years of age admitted to Pediatric Health Information System administrative database with an International Classification of Diseases diagnosis code undergoing cardiac surgery. Patients were grouped into neonates (≤30 days of age), infants (31-365 days of age), and children (>1 year) at index procedure. Primary and secondary outcomes included hospital stay and hospital costs at index surgical admission and 1- and 5-year follow-up.

RESULTS

Of the 99,670 cohort patients, neonates comprised 27% and had the highest total hospital costs, though daily hospital costs were lower. Mortality declined (5.6% in 2004 versus 2.5% in 2015, p < 0.0001) while inpatient costs rose (5% increase/year, p < 0.0001). Neonates had greater index diagnosis complexity, greater inpatient costs, required the greatest ICU resources, pharmacotherapy, and respiratory therapy. We found no relationship between hospital surgical volume, mortality, and hospital costs. Neonates had higher cumulative hospital costs at 1- and 5-year follow-up compared to infants and children.

CONCLUSIONS

Inpatient hospital costs rose during the study period, driven primarily by longer stay. Neonates had greater complexity index diagnosis, required greater hospital resources, and have higher hospital costs at 1 and 5 years compared to older children. Surgical volume and in-hospital mortality were not associated with costs. Further analyses comprising merged clinical and administrative data are necessary to identify longer stay and cost drivers after paediatric cardiac surgery.

Novel cfDNA Methylation Biomarkers Reveal Delayed Cardiac Cell Death after Open-heart Surgery

The use of cardiopulmonary bypass (CPB) is thought to cause delayed cardiac damage. DNA methylation-based liquid biopsies are novel biomarkers for monitoring acute cardiac cell death. We assessed cell-free DNA molecules as markers for cardiac damage after open-heart surgery. Novel cardiomyocyte-specific DNA methylation markers were applied to measure cardiac cfDNA in the plasma of 42 infants who underwent open-heart surgery. Cardiac cfDNA was elevated following surgery, reflecting direct surgery-related tissue damage, and declined thereafter in most patients. The concentration of cardiac cfDNA post-surgery correlated with the duration of CPB and aortic cross clamping. Strikingly, cardiac cfDNA at 6 h predicted duration of mechanical ventilation and maximal vasoactive-inotropic score better than did maximal troponin levels. Cardiac cfDNA reveals heart damage associated with CPB, and can be used to monitor cardiac cell death, to predict clinical outcome of surgery and to assess performance of cardioprotective interventions.

Outcomes of Children with Unoperated Congenital Heart Disease Admitted to PICU-A Single-Center Experience

OBJECTIVES

To evaluate the outcomes of children with congenital heart disease (CHD) awaiting surgery admitted to a pediatric intensive care unit (PICU) with acute illness.

METHODS

In this retrospective study from a single center, the outcomes of children up to 18 y of age with unoperated CHD admitted to PICU with acute illness and factors affecting the outcomes, were evaluated.

RESULTS

Fifty-eight (41 boys) children were included. Median age was 3.2 (1.5, 6) mo. Thirty-six (62%) children had acyanotic CHD (ACHD), and 22 (38%) had cyanotic CHD (CCHD). Most common ACHD was ventricular septal defect (n = 14; 38.8%) and CCHD was double-outlet right ventricle (n = 6; 27.2%). Twenty-four (41%) children underwent surgery - 10 (41.6%) palliative procedure and 14 (58.3%) corrective procedure. Hospital mortality was 50%. Of the operated children, 37.5% died and of the nonoperated children, 58.8% died. Type of the heart disease and surgical intervention was not associated with mortality (p = 0.27 and 0.11). Requirement of vasoactive agents was associated with increased mortality (p = 0.02). In children with ACHD, factors associated with mortality were lower score for weight for age (p = 0.03) and weight for length (p = 0.04), lower admission pH (p = 0.02), hemodynamic instability at admission (p = 0.002), and requirement of vasoactive agents (p = 0.04).

CONCLUSION

Children with unoperated CHD with acute illness have high morbidity and mortality. Early diagnosis and surgical interventions in children with CHD are warranted.

TRIAL REGISTRATION

Trial Registration No. IECPG-571/21.10.2020.

Associations With Extubation Failure and Predictive Value of Risk Analytics Algorithms With Extubation Readiness Tests Following Congenital Cardiac Surgery

OBJECTIVES

Extubation failure is associated with morbidity and mortality in children following cardiac surgery. Current extubation readiness tests (ERT) do not consider the nonrespiratory support provided by mechanical ventilation (MV) for children with congenital heart disease. We aimed to identify factors associated with extubation failure in children following cardiac surgery and assess the performance of two risk analytics algorithms for patients undergoing an ERT.

DESIGN

Retrospective cohort study.

SETTING

CICU at a tertiary-care children's hospital.

PATIENTS

Children receiving MV greater than 48 hours following cardiac surgery between January 1, 2017, and December 31, 2019.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Six hundred fifty encounters were analyzed with 49 occurrences (8%) of reintubation. Extubation failure occurred most frequently within 6 hours of extubation. On multivariable analysis, younger age (per each 3-mo decrease: odds ratio [OR], 1.06; 95% CI, 1.001-1.12), male sex (OR, 2.02; 95% CI, 1.03-3.97), Society of Thoracic Surgery-European Association for Cardiothoracic Surgery category 5 procedure (p equals to 0.005), and preoperative respiratory support (OR, 2.08; 95% CI, 1.09-3.95) were independently associated with unplanned reintubation. Our institutional ERT had low sensitivity to identify patients at risk for reintubation (23.8%; 95% CI, 9.7-47.6%). The addition of the inadequate delivery of oxygen (IDO2) index to the ERT increased the sensitivity by 19.0% (95% CI, -2.5 to 40.7%; p = 0.05), but the sensitivity remained low and the accuracy of the test dropped by 8.9% (95% CI, 4.7-13.1%; p < 0.01).

CONCLUSIONS

Preoperative respiratory support, younger age, and more complex operations are associated with postoperative extubation failure. IDO2 and IVCO2 provide unique cardiorespiratory monitoring parameters during ERTs but require further investigation before being used in clinical evaluation for extubation failure.

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

BACKGROUND

As the cardiac community strives to improve outcomes, accurate methods of risk stratification are imperative. Since adoption of International Classification of Disease-10th Revision (ICD-10) in 2015, there is no published method for congenital heart surgery risk stratification for administrative data.

OBJECTIVES

This study sought to develop an empirically derived, publicly available Risk Stratification for Congenital Heart Surgery (RACHS-2) tool for ICD-10 administrative data.

METHODS

The RACHS-2 stratification system was iteratively and empirically refined in a training dataset of Pediatric Health Information Systems claims to optimize sensitivity and specificity compared with corresponding locally held Society of Thoracic Surgeons-Congenital Heart Surgery (STS-CHS) clinical registry data. The tool was validated in a second administrative data source: New York State Medicaid claims. Logistic regression was used to compare the ability of RACHS-2 in administrative data to predict operative mortality vs STAT Mortality Categories in registry data.

RESULTS

The RACHS-2 system captured 99.6% of total congenital heart surgery registry cases, with 1.0% false positives. RACHS-2 predicted operative mortality in both training and validation administrative datasets similarly to STAT Mortality Categories in registry data. C-statistics for models for operative mortality in training and validation administrative datasets-adjusted for RACHS-2-were 0.76 and 0.84 (95% CI: 0.72-0.80 and 0.80-0.89); C-statistics for models for operative mortality-adjusted for STAT Mortality Categories-in corresponding clinical registry data were 0.75 and 0.84 (95% CI: 0.71-0.79 and 0.79-0.89).

CONCLUSIONS

RACHS-2 is a risk stratification system for pediatric cardiac surgery for ICD-10 administrative data, validated in 2 administrative-registry-linked datasets. Statistical code is publicly available upon request.

Characteristics of in-hospital mortality of congenital heart disease (CHD) after surgical treatment in children from 2005 to 2017: a single-center experience

Background

To evaluate trends in the in-hospital mortality rate for pediatric cardiac surgery procedures between 2005 and 2017 in our center, and to discuss the mortality characteristics of children’s CHD after thoracotomy.

Methods

This retrospective data were collected from medical records of children underwent CHD surgery between 2005 and 2017.

Results

A total of 19,114 children with CHD underwent surgery and 444 children died, with the in-hospital mortality was 2.3%. Complex mixed defect CHD had the highest fatality rate (8.63%), left obstructive lesion CHD had the second highest fatality rate (4.49%), right to left shunt CHD had the third highest mortality rate (3.51%), left to right shunt CHD had the lowest mortality rate (χ2 = 520.3,P < 0.05). The neonatal period has the highest mortality rate (12.17%), followed by infant mortality (2.58%), toddler age mortality (1.16%), and preschool age mortality (0.94%), the school age and adolescent mortality rate was the lowest (χ2 = 529.3,P < 0.05). In addition, the fatality rate in boys was significantly higher than that in girls (2.77% versus 1.62%, χ2 = 26.4, P < 0.05).

Conclusions

The mortality rate of CHD surgery in children decreased year by year. The younger the age and the more complicated the cyanotic heart disease, the higher the mortality rate may be.

Benchmarking in Congenital Heart Surgery Using Machine Learning-Derived Optimal Classification Trees

Background: We have previously shown that the machine learning methodology of optimal classification trees (OCTs) can accurately predict risk after congenital heart surgery (CHS). We have now applied this methodology to define benchmarking standards after CHS, permitting case-adjusted hospital-specific performance evaluation. Methods: The European Congenital Heart Surgeons Association Congenital Database data subset (31 792 patients) who had undergone any of the 10 "benchmark procedure group" primary procedures were analyzed. OCT models were built predicting hospital mortality (HM), and prolonged postoperative mechanical ventilatory support time (MVST) or length of hospital stay (LOS), thereby establishing case-adjusted benchmarking standards reflecting the overall performance of all participating hospitals, designated as the "virtual hospital." These models were then used to predict individual hospitals' expected outcomes (both aggregate and, importantly, for risk-matched patient cohorts) for their own specific cases and case-mix, based on OCT analysis of aggregate data from the "virtual hospital." Results: The raw average rates were HM = 4.4%, MVST = 15.3%, and LOS = 15.5%. Of 64 participating centers, in comparison with each hospital's specific case-adjusted benchmark, 17.0% statistically (under 90% confidence intervals) overperformed and 26.4% underperformed with respect to the predicted outcomes for their own specific cases and case-mix. For MVST and LOS, overperformers were 34.0% and 26.4%, and underperformers were 28.3% and 43.4%, respectively. OCT analyses reveal hospital-specific patient cohorts of either overperformance or underperformance. Conclusions: OCT benchmarking analysis can assess hospital-specific case-adjusted performance after CHS, both overall and patient cohort-specific, serving as a tool for hospital self-assessment and quality improvement.

Capturing Adult Congenital Heart Disease: Framework for Development of an ACHD Mortality Risk Model

BACKGROUND

As a formative step toward development of adult congenital heart disease (ACHD) risk-adjusted metrics, we describe the STS ACHD population, procedural frequency, and early mortality.

METHODS

Adults (>18 years) with CHD (2014-2019) were identified in the STS Adult Cardiac Surgery (ASCD) and the Congenital Heart Surgery (CHSD) Databases. Following deduplication, variable mapping, data concatenation, and harmonization of pre-procedure factors, procedures were grouped and unadjusted mortality catalogued for overall cohort and the cohort excluding patients with isolated bicuspid aortic valve (BAV).

RESULTS

Among 171,186 ACSD and 18,281 CHSD records, 152,731 unique records met inclusion criteria. Twenty-eight congenital diagnoses accounted for 86% of the overall cohort, and prevalence of ACHD increased over the study timeframe. ACHD patients underwent operations to treat both acquired and CHD. Most common procedures overall and after excluding isolated BAV were: aortic valve replacement (AVR), ascending aortic surgery, and coronary artery bypass grafting (CABG). After excluding isolated BAV, major procedure combinations occurred in 46% (31% had 2 and 3% >4 major procedures) and most prevalent combinations included: AVR + CABG (n=2,352), AVR + subaortic stenosis repair (n=1,481) and AVR + ascending aortic surgery (n=1,239). Unadjusted 30-day mortality was procedure dependent, 2.8% overall and 3.6% with isolated BAV excluded.

CONCLUSIONS

The ACHD surgical population is heterogenous, and patients undergo surgery for CHD-related and adult/acquired procedure combinations. Early mortality is variable and influenced by surgical complexity. Excluding isolated BAV patients and developing procedure-based ACHD mortality risk models may be ideal but will require empirically-derived grouping and collaboration.

Outcomes of Infants Undergoing Modified Blalock-Taussig Shunt Procedures in Oman: A retrospective study

Objectives

A modified Blalock-Taussig (mBT) shunt procedure is a common palliative surgery used to treat infants and children with cyanotic congenital heart disease (CCHD). This study aimed to report the outcomes of infants and children undergoing mBT shunt procedures in Oman. In addition, risk factors associated with early mortality, inter-stage mortality and reintervention were assessed.

Methods

This retrospective cohort study was conducted from January 2016 to December 2018 at the National Heart Centre, Muscat, Oman. All paediatric patients with CCHD undergoing mBT shunt procedures as a primary palliative procedure during this period were included. Data were retrieved from electronic hospital records. Kaplan-Meier survival curves were used to describe overall survival.

Results

A total of 50 infants and children were included in this study. The in-hospital mortality and interstage mortality rates were 10% and 6.7%, respectively. Preoperative mechanical ventilation (odds ratio [OR] = 3.00, 95% confidence interval [CI]: 1.98–4.76; P = 0.007) and cardiopulmonary bypass (OR = 4.09, 95% CI: 2.44–6.85; P = 0.002) were significant risk factors for early mortality. In-hospital and interval surgical reintervention rates were 12% and 13.3%, respectively. Following the primary shunt procedure, the median time to second-stage surgery was 15.5 months (range: 5.0–34.0 months).

Conclusion

The findings of this study support those reported in international research regarding the risks associated with mBT shunt surgeries. In particular, preoperative mechanical ventilation and cardiopulmonary bypass were significant risk factors for early mortality.

Risk evaluation in adult congenital heart surgery: analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database risk models on data from the European Congenital Heart Surgeons Association Congenital Database

 

OBJECTIVES

We sought to evaluate the predictive power of the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) mortality score and the adult congenital heart surgery (ACHS) mortality score for the adults undergoing congenital heart operations entered into the European Congenital Heart Surgeons Association (ECHSA) database.

METHODS

The data set comprised 17 662 major operations performed between 1997 and 2019, on patients 18 years of age or older, in European centres participating in the ECHSA database. Each operation was assigned a STAT mortality score and category and an ACHS mortality score. Operative mortality was based on the 30-day status and on the status at hospital discharge. The discriminatory power of the STAT and ACHS scores was assessed using the area under the receiver operating characteristic curve (c-index).

RESULTS

A total of 17 214 (97.46%) operations were assigned ACHS scores. The 3 most frequent primary procedures were closure of the atrial septal defect (19.0%), aortic valve replacement (8.8%) and non-valve-sparing aortic root replacement (6.1%). Operative mortality for ACHS-coded operations was 2.07%. The procedures with the highest mortality were atrial septal defect creation/enlargement (19.0%), lung transplantation (18.8%) and heart transplantation (18.2%). A total of 17 638 (99.86%) operations were assigned a STAT score and category. The operative mortality for STAT-coded operations was 2.27%. The c-index for mortality was 0.720 for the STAT mortality score and 0.701 for the ACHS score.

CONCLUSIONS

The ACHS mortality score and the STAT mortality score reached similar, moderate predictive power in adult patients undergoing congenital heart surgery in ECHSA database.

Prognostic Model to Predict Postoperative Adverse Events in Pediatric Patients With Aortic Coarctation

Background: Postoperative adverse events remain excessively high in surgical patients with coarctation of aorta (CoA). Currently, there is no generally accepted strategy to predict these patients' individual outcomes.

Objective: This study aimed to develop a risk model for the prediction of postoperative risk in pediatric patients with CoA.

Methods: In total, 514 patients with CoA at two centers were enrolled. Using daily clinical practice data, we developed a model to predict 30-day or in-hospital adverse events after the operation. The least absolute shrinkage and selection operator approach was applied to select predictor variables and logistic regression was used to develop the model. Model performance was estimated using the receiver-operating characteristic curve, the Hosmer–Lemeshow test and the calibration plot. Net reclassification improvement (NRI) and integrated discrimination improvement (IDI) compared with existing risk strategies were assessed.

Results: Postoperative adverse events occurred in 195 (37.9%) patients in the overall population. Nine predictive variables were identified, including incision of left thoracotomy, preoperative ventilation, concomitant ventricular septal defect, preoperative cardiac dysfunction, severe pulmonary hypertension, height, weight-for-age z-score, left ventricular ejection fraction and left ventricular posterior wall thickness. A multivariable logistic model [area under the curve = 0.8195 (95% CI: 0.7514–0.8876)] with adequate calibration was developed. Model performance was significantly improved compared with the existing Aristotle Basic Complexity (ABC) score (NRI = 47.3%, IDI = 11.5%) and the Risk Adjustment for Congenital Heart Surgery (RACHS-1) (NRI = 75.0%, IDI = 14.9%) in the validation set.

Conclusion: Using daily clinical variables, we generated and validated an easy-to-apply postoperative risk model for patients with CoA. This model exhibited a remarkable improvement over the ABC score and the RACHS-1 method.

Resolution of postnatal shock before open-heart surgery in neonates with prenatal diagnoses

BACKGROUND

The impact of prenatal diagnosis (PreND) for congenital heart disease on outcomes after neonatal open heart surgery is undetermined. We hypothesized that PreND has a positive impact on surgical outcomes in terms of immediate postnatal intensive care, which may lead to a decreased risk of persistent shock before surgery.

METHODS

Among the 949 neonates who underwent open heart surgery between January 2002 and December 2017, 655 patients (69.0%) were diagnosed prenatally (Group-PreND) and 294 patients (31.0%) were diagnosed postnatally (Group-PostND). Procedural complexity, incidence of postnatal shock (Serum lactate >4.0 mmol/L or pH <7.2), hospitalization timing, duration of shock, resolution of shock, and in-hospital mortality were compared between the two groups.

RESULTS

In Group-PreND, procedure-dependent comprehensive Aristotle score (10.8 vs. 10.0 P < .001), incidence of extra-cardiac anomalies (13.0% vs. 7.1%, P = .008), heterotaxy syndrome (3.8% vs. 1.0%, P = .021), and postnatal shock (244/655, 37.3% vs. 78/294, 26.5%, P = .001) were higher than in Group-postND. However, patients in Group-PreND were hospitalized earlier after birth (0 day vs 5 days, P < .001), experiencing shorter duration of shock (5.3 hours vs 9.0 hours, P = .01), and, consequently, showing higher incidence of shock resolution (212/244, 87% vs. 52/78, 67%, P < .001). In-hospital mortality was comparable between the two groups (P = .070).

CONCLUSIONS

Postnatal shock is more frequently observed in Group-PreND. However, prenatal awareness of the disease leads to immediate postnatal initiation of intensive care with shorter exposure to shock, leading to higher probability of shock resolution.

Adverse Outcomes Prediction for Congenital Heart Surgery: A Machine Learning Approach

OBJECTIVE

Risk assessment tools typically used in congenital heart surgery (CHS) assume that various possible risk factors interact in a linear and additive fashion, an assumption that may not reflect reality. Using artificial intelligence techniques, we sought to develop nonlinear models for predicting outcomes in CHS.

METHODS

We built machine learning (ML) models to predict mortality, postoperative mechanical ventilatory support time (MVST), and hospital length of stay (LOS) for patients who underwent CHS, based on data of more than 235,000 patients and 295,000 operations provided by the European Congenital Heart Surgeons Association Congenital Database. We used optimal classification trees (OCTs) methodology for its interpretability and accuracy, and compared to logistic regression and state-of-the-art ML methods (Random Forests, Gradient Boosting), reporting their area under the curve (AUC or c-statistic) for both training and testing data sets.

RESULTS

Optimal classification trees achieve outstanding performance across all three models (mortality AUC = 0.86, prolonged MVST AUC = 0.85, prolonged LOS AUC = 0.82), while being intuitively interpretable. The most significant predictors of mortality are procedure, age, and weight, followed by days since previous admission and any general preoperative patient risk factors.

CONCLUSIONS

The nonlinear ML-based models of OCTs are intuitively interpretable and provide superior predictive power. The associated risk calculator allows easy, accurate, and understandable estimation of individual patient risks, in the theoretical framework of the average performance of all centers represented in the database. This methodology has the potential to facilitate decision-making and resource optimization in CHS, enabling total quality management and precise benchmarking initiatives.

Association Between Preoperative Factors and In-hospital Mortality in Neonates After Cardiac Surgery in China

Background: Little is known about preoperative factors affecting cardiac surgery outcomes of neonates in China. We sought to examine the association between characteristics of neonates with congenital heart disease (CHD) and early postoperative outcomes after cardiac repair in a tertiary care paediatric hospital. Methods: A single-centre retrospective cohort study of neonates who underwent cardiac surgery between January 2006 and December 2019 was performed. Demographic, institutional, and surgical characteristics of neonates were examined and their association with in-hospital mortality was analysed using multivariable logistic regression models. Results: During the study period, we analysed the outcomes of 1,078 neonates. In-hospital mortality decreased to 13.8% in the era 2017-2019. The overall in-hospital mortality rate was 16.3%. Normal weight at surgery [odds ratio (OR), 0.63; 95% confidence interval (CI), 0.47-0.85; P = 0.003] was associated with lower mortality risk. Poor health status (emergent: OR, 3.11; 95% CI, 1.96-4.94; P < 0.001; elective: OR, 1.63; 95% CI, 1.11-2.40; P = 0.013), higher Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) categories (STAT 5 category: OR, 2.58; 95% CI, 1.04-6.43; P = 0.042), and limited individual surgeon experience (surgeon with 5-10 operations per year: OR, 1.43; 95% CI, 1.06-1.95; P = 0.021) were associated with higher odds of early death. Conclusion: In-hospital mortality after neonatal cardiac surgery remained high in our centre over the past 10 years. Some preoperative aspects, including low-weight at surgery, poor health status, increased surgical complexity, and limited surgeon experience were significantly associated with higher mortality. Based on the observed associations, the necessary practises to be modified, especially in preoperative care, should be identified and assessed in future research.

RACHS - ANZ : A Modified Risk Adjustment in Congenital Heart Surgery Model for Outcome Surveillance in Australia and New Zealand

Background

Outcomes for pediatric cardiac surgery are commonly reported from international databases compiled from voluntary data submissions. Surgical outcomes for all children in a country or region are less commonly reported. We aimed to describe the bi‐national population‐based outcome for children undergoing cardiac surgery in Australia and New Zealand and determine whether the Risk Adjustment for Congenital Heart Surgery (RACHS) classification could be used to create a model that accurately predicts in‐hospital mortality in this population.

Methods and Results

The study was conducted in all children's hospitals performing cardiac surgery in Australia and New Zealand between January 2007 and December 2015. The performance of the original RACHS‐1 model was assessed and compared with an alternative RACHS‐ANZ (Australia and New Zealand) model, developed balancing discrimination with parsimonious variable selection. A total of 14 324 hospital admissions were analyzed. The overall hospital mortality was 2.3%, ranging from 0.5% for RACHS category 1 procedures, to 17.0% for RACHS category 5 or 6 procedures. The original RACHS‐1 model was poorly calibrated with death overpredicted (1161 deaths predicted, 289 deaths observed). The RACHS‐ANZ model had better performance in this population with excellent discrimination (Az‐ROC of 0.830) and acceptable Hosmer and Lemeshow goodness‐of‐fit (P=0.216).

Conclusions

The original RACHS‐1 model overpredicts mortality in children undergoing heart surgery in the current era. The RACHS‐ANZ model requires only 3 risk variables in addition to the RACHS procedure category, can be applied to a wider range of patients than RACHS‐1, and is suitable to use to monitor regional pediatric cardiac surgery outcomes.

Cerebral oxygenation during pediatric congenital cardiac surgery and its association with outcome: a retrospective observational study

Purpose

Non-invasive cerebral oxygen saturation (ScO₂) monitoring is an established tool in the intraoperative phase of pediatric congenital cardiac surgery (CCS). This study investigated the association between ScO₂ and postoperative outcome by investigating both baseline ScO₂ values and intraoperative desaturations from baseline.

Methods

All CCS procedures performed in the period 2010-2017 in our institution in which ScO₂ was monitored were included in this historical cohort study. Baseline ScO₂ was determined after tracheal intubation, before surgical incision. Subgroups were based on cardiac pathology and degree of intracardiac shunting. Poor outcome was defined based on length of stay (LOS) in the intensive care unit (ICU)/hospital, duration of mechanical ventilation (MV), and 30-day mortality. Intraoperatively, ScO₂ total time below baseline (TBBL) and ScO₂ time-weighted average (TWA) were calculated.

Results

Data from 565 patients were analyzed. Baseline ScO₂ was significantly associated with LOS in ICU (odds ratio [OR] per percentage decrease in baseline ScO₂, 0.95; 95% confidence interval [CI], 0.93 to 0.97; P < 0.001), with LOS in hospital (OR, 0.93; 95% CI, 0.91 to 0.96; P < 0.001), with MV duration (OR, 0.92; 95% CI, 0.90 to 0.95; P < 0.001) and with 30-day mortality (OR, 0.94; 95% CI, 0.91 to 0.98; P = 0.007). Cerebral oxygen saturation TWA had no associations, while ScO₂ TBBL had only a small association with LOS in ICU (OR, 1.02; 95% CI, 1.01 to 1.03; P < 0.001), MV duration (OR,1.02; 95% CI, 1.01 to 1.03; P = 0.002), and LOS in hospital (OR, 1.02; 95% CI, 1.01 to 1.04; P < 0.001).

Conclusion

In pediatric patients undergoing cardiac surgery, low baseline ScO₂ values measured after tracheal intubation were associated with several adverse postoperative outcomes. In contrast, the severity of actual intraoperative cerebral desaturation was not associated with postoperative outcomes. Baseline ScO₂ measured after tracheal intubation may help identify patients at increased perioperative risk.

Associations between anthropometric indices and outcomes of congenital heart operations in infants and young children: An analysis of data from the Society of Thoracic Surgeons Database

BACKGROUND

Children with congenital heart disease are at risk for growth failure due to inadequate nutrient intake and increased metabolic demands. We examined the relationship between anthropometric indices of nutrition (height-for-age z-score [HAZ], weight-for-age z-score [WAZ], weight-for-height z-score [WHZ]) and outcomes in a large sample of children undergoing surgery for congenital heart disease.

METHODS

Patients in the Society of Thoracic Surgeons Congenital Heart Surgery Database having index cardiac surgery at age 1 month to 10 years were included. Indices were calculated by comparing patients' weight and height to population norms from the World Health Organization and Centers for Disease Control and Prevention. Outcomes included operative mortality, composite mortality or major complication, major postoperative infection, and postoperative length of stay. For each outcome and index, the adjusted odds ratio (aOR) (for mortality, composite outcome, and infection) and adjusted relative change in median (for postoperative length of stay) for a 1-unit decrease in index were estimated using mixed-effects logistic and log-linear regression models.

RESULTS

Every unit decrease in HAZ was associated with 1.40 aOR of mortality (95% CI 1.32-1.48), and every unit decrease in WAZ was associated with 1.33 aOR for mortality (95% CI 1.25-1.41). The relationship between WHZ and outcome was nonlinear, with aOR of mortality of 0.84 (95% CI 0.76-0.93) for 1-unit decrease when WHZ ≥ 0 and a nonsignificant association for WHZ < 0. Trends for other outcomes were similar. Overall, the incidence of low nutritional indices was similar for 1-ventricle and 2-ventricle patients. Children between the age of 1 month and 1 year and those with lesions associated with pulmonary overcirculation had the highest incidence of low nutritional indices.

CONCLUSIONS

Lower HAZ and WAZ, suggestive of malnutrition, are associated with increased mortality and other adverse outcomes after cardiac surgery in infants and young children. Higher WHZ over zero, suggestive of obesity, is also associated with adverse outcomes.

Recent Surgical Outcomes of Congenital Heart Disease according to Korea Heart Foundation Data

BACKGROUND AND OBJECTIVES

This study presents an update of the surgical outcomes of congenital heart disease (CHD) according to Korea Heart Foundation (KHF) data.

METHODS

We investigated the data of the 7,305 patients who were economically supported by KHF in 2000-2014. Of them, we analyzed surgical outcomes of the 6,599 patients who underwent CHD surgery.

RESULTS

The median patient age was 1.9 years (range, 0-71.5 years). Of the 6,599 patients, 5,616 (85.1%) underwent biventricular repair and 983 (14.9%) underwent palliative procedures. The mean Basic Aristotle Score was 6.6±2.2. A complex procedure (defined as Basic Aristotle Score above 6) was performed in 3,368 patients (51.0%). The early mortality rate was 3.8%, while the late mortality rate was 1.8%. Previous reports of the KHF (1984-1999) showed that the early surgical and late mortality rates were 8.6%, and 5.3%, respectively. There were 491 neonates (7.4%); among them, the early mortality rate was 12.2% and late mortality rate was 3.7%. There were 2,617 infants (40.0%); among them, the early mortality rate was 6.0% and the late mortality rate was 2.3%. A total of 591 patients from 30 countries were helped by the KHF.

CONCLUSIONS

More neonatal surgeries (491 vs. 74 patients) were performed than those in the past (1984-1999). The surgical outcomes were much better than before. Our surgical outcomes revealed that the Republic of Korea has been transformed from a country receiving help to a country that helps other low socioeconomic status countries.

Association between preoperative respiratory support and outcomes in paediatric cardiac surgery

BACKGROUND

Preoperative mechanical ventilation is associated with morbidity and mortality following CHD surgery, but prior studies lack a comprehensive analysis of how preoperative respiratory support mode and timing affects outcomes.

METHODS

We retrospectively collected data on children <18 years of age undergoing cardiac surgery at an academic tertiary care medical centre. Using multivariable regression, we examined the association between modes of preoperative respiratory support (nasal cannula, high-flow nasal cannula/noninvasive ventilation, or invasive mechanical ventilation), escalation of preoperative respiratory support, and invasive mechanical ventilation on the day of surgery for three outcomes: operative mortality, postoperative length of stay, and postoperative complications. We repeated our analysis in a subcohort of neonates.

RESULTS

A total of 701 children underwent 800 surgical procedures, and 40% received preoperative respiratory support. Among neonates, 243 patients underwent 253 surgical procedures, and 79% received preoperative respiratory support. In multivariable analysis, all modes of preoperative respiratory support, escalation in preoperative respiratory support, and invasive mechanical ventilation on the day of surgery were associated with increased odds of prolonged length of stay in children and neonates. Children (odds ratio = 3.69, 95% CI 1.2-11.4) and neonates (odds ratio = 8.97, 95% CI 1.31-61.14) on high-flow nasal cannula/noninvasive ventilation had increased odds of operative mortality compared to those on room air.

CONCLUSION

Preoperative respiratory support is associated with prolonged length of stay and mortality following CHD surgery. Knowing how preoperative respiratory support affects outcomes may help guide surgical timing, inform prognostic conversations, and improve risk stratification models.

Ten Years of Data Verification: The Society of Thoracic Surgeons Congenital Heart Surgery Database Audits

BACKGROUND

The completeness and accuracy of data contained within clinical databases and registries is critical to the reliability of reports emanating from these platforms. Therefore, vigorous data verification processes are a core competency of any mature database or registry. The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS CHSD) has conducted audits of participant data for just over ten years. This report documents the validity of data elements within the STS CHSD.

METHODS

We review the various elements of a robust audit process, detail the STS CHSD audit methodology, and report completeness and agreement rates for all adjudicated fields in the most recently completed audit.

RESULTS

The rate of completeness for general data elements was 97.6% and the rate of agreement was 97.4%. The rate of completeness for variables in the mortality review was 100% and the rate of agreement was 99.3%.

CONCLUSIONS

The STS CHSD audit is a highly structured and reproducible process. The most recently completed audit documents a very high level of completeness and accuracy of data variables, particularly those most germane to outcomes measurement.

Trends in Long-Term Mortality After Congenital Heart Surgery

BACKGROUND

Congenital heart surgery has improved the survival of patients with even the most complex defects, but the long-term survival after these procedures has not been fully described.

OBJECTIVES

The purpose of this study was to evaluate the long-term survival of patients (age <21 years) who were operated on for congenital heart defects (CHDs).

METHODS

This study used the Pediatric Cardiac Care Consortium data, a U.S.-based, multicenter registry of pediatric cardiac surgery. Survival analysis included 35,998 patients who survived their first congenital heart surgery at <21 years of age and had adequate identifiers for linkage with the National Death Index through 2014. Survival was compared to that in the general population using standardized mortality ratios (SMRs).

RESULTS

After a median follow-up of 18 years (645,806 person-years), 3,191 deaths occurred with an overall SMR of 8.3 (95% confidence interval [CI]: 8.0 to 8.7). The 15-year SMR decreased from 12.7 (95% CI: 11.9 to 13.6) in the early era (1982 to 1992) to 10.0 (95% CI: 9.3 to 10.8) in the late era (1998 to 2003). The SMR remained elevated even for mild forms of CHD such as patent ductus arteriosus (SMR 4.5) and atrial septal defects (SMR 4.9). The largest decreases in SMR occurred for patients with transposition of great arteries (early: 11.0 vs. late: 3.8; p < 0.05), complete atrioventricular canal (31.3 vs. 15.3; p < 0.05), and single ventricle (53.7 vs. 31.3; p < 0.05).

CONCLUSIONS

In this large U.S. cohort, long-term mortality after congenital heart surgery was elevated across all forms of CHD. Survival has improved over time, particularly for severe defects with significant changes in their management strategy, but still lags behind the general population.

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.

Early postoperative measurement of fibroblast growth factor 23 predicts severe acute kidney injury in infants after cardiac surgery

Aims: Acute kidney injury (AKI) occurs in 30 – 40% of children after cardiac surgery (CS) and is associated with poor prognosis. Fibroblast growth factor 23 (FGF23) is a bone-derived hormone with a pivotal role in phosphorus and vitamin D metabolism. We assessed FGF23 as an early marker for severe AKI (sAKI) in infants after CS. Materials and methods: Samples were previously collected in a multicenter observational study from children after CS. Serum FGF23 (n = 41) and urine AKI biomarker levels (n = 35) were assessed 4 – 8 hours after bypass. sAKI was defined as ≥ 100% rise in serum creatinine over baseline. Non-parametric and ROC analyses were used to evaluate the association between FGF23, urine AKI markers, and sAKI in the week after CS. Results: Serum FGF23, urine NGAL, and urine KIM1 were higher in sAKI patients. The AUC-ROC for urine NGAL (0.74, [0.49 – 0.99]), urine KIM1 (0.79, [0.68 – 0.98]), and serum FGF23 (0.74, [0.5 – 0.9]) showed fair prediction of sAKI. Conclusion: Early measurement of FGF23 has predictive ability in infants who develop sAKI after CS with cardiopulmonary bypass.

A novel risk classification system for 30-day mortality in children undergoing surgery

A simple, objective and accurate way of grouping children undergoing surgery into clinically relevant risk groups is needed. The purpose of this study, is to develop and validate a preoperative risk classification system for postsurgical 30-day mortality for children undergoing a wide variety of operations. The National Surgical Quality Improvement Project-Pediatric participant use file data for calendar years 2012-2014 was analyzed to determine preoperative variables most associated with death within 30 days of operation (D30). Risk groups were created using classification tree analysis based on these preoperative variables. The resulting risk groups were validated using 2015 data, and applied to neonates and higher risk CPT codes to determine validity in high-risk subpopulations. A five-level risk classification was found to be most accurate. The preoperative need for ventilation, oxygen support, inotropic support, sepsis, the need for emergent surgery and a do not resuscitate order defined non-overlapping groups with observed rates of D30 that vary from 0.075% (Very Low Risk) to 38.6% (Very High Risk). When CPT codes where death was never observed are eliminated or when the system is applied to neonates, the groupings remained predictive of death in an ordinal manner.

Improving risk adjustment in the PRAiS (Partial Risk Adjustment in Surgery) model for mortality after paediatric cardiac surgery and improving public understanding of its use in monitoring outcomes

Background

In 2011, we developed a risk model for 30-day mortality after children’s heart surgery. The PRAiS (Partial Risk Adjustment in Surgery) model uses data on the procedure performed, diagnosis, age, weight and comorbidity. Our treatment of comorbidity was simplistic because of data quality. Software that implements PRAiS is used by the National Congenital Heart Disease Audit (NCHDA) in its audit work. The use of PRAiS triggered the temporary suspension of surgery at one unit in 2013. The public anger that surrounded this illustrated the need for public resources around outcomes monitoring.

Objectives

(1) To improve the PRAiS risk model by incorporating more information about comorbidities. (2) To develop online resources for the public to help them to understand published mortality data.

Design

Objective 1 The outcome measure was death within 30 days of the start of each surgical episode of care. The analysts worked with an expert panel of clinical and data management representatives. Model development followed an iterative process of clinical discussion of risk factors, development of regression models and assessment of model performance under cross-validation. Performance was measured using the area under the receiving operator characteristic (AUROC) curve and calibration in the cross-validation test sets. The final model was further assessed in a 2014–15 validation data set.Objective 2 We developed draft website material that we iteratively tested through four sets of two workshops (one workshop for parents of children who had undergone heart surgery and one workshop for other interested users). Each workshop recruited new participants. The academic psychologists ran two sets of three experiments to explore further understanding of the web content.

Data

We used pseudonymised NCHDA data from April 2009 to April 2014. We later unexpectedly received a further year of data (2014–15), which became a prospective validation set.

Results

Objective 1The cleaned 2009–14 data comprised 21,838 30-day surgical episodes, with 539 deaths. The 2014–15 data contained 4207 episodes, with 97 deaths. The final regression model included four new comorbidity groupings. Under cross-validation, the model had a median AUROC curve of 0.83 (total range 0.82 to 0.83), a median calibration slope of 0.92 (total range 0.64 to 1.25) and a median intercept of –0.23 (range –1.08 to 0.85). In the validation set, the AUROC curve was 0.86 [95% confidence interval (CI) 0.83 to 0.89], and its calibration slope and intercept were 1.01 (95% CI 0.83 to 1.18) and 0.11 (95% CI –0.45 to 0.67), respectively. We recalibrated the final model on 2009–15 data and updated the PRAiS software.Objective 2We coproduced a website (http://childrensheartsurgery.info/) that provides interactive exploration of the data, two animations and background information. It was launched in June 2016 and was very well received.

Limitations

We needed to use discharge status as a proxy for 30-day life status for the 14% of overseas patients without a NHS number. We did not have sufficient time or resources to extensively test the usability and take-up of the website following its launch.

Conclusions

The project successfully achieved its stated aims. A key theme throughout has been the importance of collaboration and coproduction. In particular for aim 2, we generated a great deal of generalisable learning about how to communicate complex clinical and mathematical information.

Further work

Extending our codevelopment approach to cover many other aspects of quality measurement across congenital heart disease and other specialised NHS services.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Increased Atrial β-Adrenergic Receptors and GRK-2 Gene Expression Can Play a Fundamental Role in Heart Failure After Repair of Congenital Heart Disease with Cardiopulmonary Bypass

Surgeries to correct congenital heart diseases are increasing in Brazil and worldwide. However, even with the advances in surgical techniques and perfusion, some cases, especially the more complex ones, can develop heart failure and death. A retrospective study of patients who underwent surgery for correction of congenital heart diseases with cardiopulmonary bypass (CPB) in a university tertiary-care hospital that died, showed infarction in different stages of evolution and scattered microcalcifications in the myocardium, even without coronary obstruction. CPB is a process routinely used during cardiac surgery for congenital heart disease. However, CPB has been related to increased endogenous catecholamines that can lead to major injuries in cardiomyocytes. The mechanisms involved are not completely understood. The aim of this study was to evaluate the alterations induced in the β-adrenergic receptors and GRK-2 present in atrial cardiomyocytes of infants with congenital heart disease undergoing surgical repair with CPB and correlate the alterations with functional and biochemical markers of ischemia/myocardial injury. The study consisted of right atrial biopsies of infants undergoing surgical correction in HC-FMRPUSP. Thirty-three cases were selected. Atrial biopsies were obtained at the beginning of CPB (group G1) and at the end of CPB (group G2). Real-time PCR, Western blotting, and immunofluorescence analysis were conducted to evaluate the expression of β₁, β₂-adrenergic receptors, and GRK-2 in atrial myocardium. Cardiac function was evaluated by echocardiography and biochemical analysis (N-terminal pro-brain natriuretic peptide (NT-ProBNP), lactate, and cardiac troponin I). We observed an increase in serum lactate, NT-proBNP, and troponin I at the end of CPB indicating tissue hypoxia/ischemia. Even without major clinical consequences in cardiac function, these alterations were followed by a significant increase in gene expression of β₁ and β₂ receptors and GRK-2, suggesting that this is one of the mechanisms responsible for the exacerbated response of cardiomyocytes to circulating catecholamines. These alterations could explain the irreversible myocardial damage and lipid peroxidation of membranes classically attributed to catecholamine excess, observed in some infants who develop heart failure and postoperative death. Although other factors may be involved, this study confirms that CPB acts as a potent inducer of increased gene expression of β- adrenergic receptors and GRK-2, making the myocardium of these infants more susceptible to the effects of circulating endogenous catecholamines, which may contribute to the development of irreversible myocardial damage and death.

Morbidity and mortality prediction in pediatric heart surgery: Physiological profiles and surgical complexity

OBJECTIVES

Outcome prediction for pediatric heart surgery has focused on mortality but mortality has been significantly reduced over the past 2 decades. Clinical care practices now emphasize reducing morbidity. Physiology-based profiles assessed by the Pediatric Risk of Mortality (PRISM) score are associated with new significant functional morbidity detected at hospital discharge. Our aims were to assess the relationship between new functional morbidity and surgical risk categories (Risk Adjustment for Congenital Heart Surgery [RACHS] and Society for Thoracic Surgery Congenital Heart Surgery Database Mortality Risk [STAT]), measure the performance of 3-level (intact survival, survival with new functional morbidity, or death) and 2-level (survival or death) PRISM prediction algorithms, and assess whether including RACHS or STAT complexity categories improves the PRISM predictive performance.

METHODS

Patients (newborn to age 18 years) were randomly selected from 7 sites (December 2011-April 2013). Morbidity (using the Functional Status Scale) and mortality were assessed at hospital discharge. The most recently published PRISM algorithms were tested for goodness of fit, and discrimination with and without the RACHS and STAT complexity categories.

RESULTS

The mortality rate in the 1550 patients was 3.2%. Significant new functional morbidity rate occurred in 4.8%, increasing from 1.8% to 13.9%, 1.7%, and 12.9% from the lowest to the highest RACHS and STAT categories, respectively. The 3-level and 2-level PRISM models had satisfactory goodness of fit and substantial discriminative ability. Inclusion of RACHS and STAT complexity categories did not improve model performance.

CONCLUSIONS

Both mortality and new, functional morbidity are important outcomes associated with surgical complexity and can be predicted using PRISM algorithms. Adding surgical complexity to the physiologic profiles does not improve predictor performance.

The Society of Thoracic Surgeons Congenital Heart Surgery Database Public Reporting Initiative

Three basic principles provide the rationale for the Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (CHSD) public reporting initiative: (1) Variation in congenital and pediatric cardiac surgical outcomes exist. (2) Patients and their families have the right to know the outcomes of the treatments that they will receive. (3). It is our professional responsibility to share this information with them in a format they can understand. The STS CHSD public reporting initiative facilitates the voluntary transparent public reporting of congenital and pediatric cardiac surgical outcomes using the STS CHSD Mortality Risk Model. The STS CHSD Mortality Risk Model is used to calculate risk-adjusted operative mortality and adjusts for the following variables: age, primary procedure, weight (neonates and infants), prior cardiothoracic operations, non-cardiac congenital anatomic abnormalities, chromosomal abnormalities or syndromes, prematurity (neonates and infants), and preoperative factors (including preoperative/preprocedural mechanical circulatory support [intraaortic balloon pump, ventricular assist device, extracorporeal membrane oxygenation, or cardiopulmonary support], shock [persistent at time of surgery], mechanical ventilation to treat cardiorespiratory failure, renal failure requiring dialysis and/or renal dysfunction, preoperative neurological deficit, and other preoperative factors). Operative mortality is defined in all STS databases as (1) all deaths, regardless of cause, occurring during the hospitalization in which the operation was performed, even if after 30 days (including patients transferred to other acute care facilities); and (2) all deaths, regardless of cause, occurring after discharge from the hospital, but before the end of the 30^th postoperative day. The STS CHSD Mortality Risk Model has good model fit and discrimination with an overall C statistics of 0.875 and 0.858 in the development sample and the validation sample, respectively. These C statistics are the highest C statistics ever seen in a pediatric cardiac surgical risk model. Therefore, the STS CHSD Mortality Risk Model provides excellent adjustment for case mix and should mitigate against risk aversive behavior. The STS CHSD Mortality Risk Model is the best available model to date for measuring outcomes after pediatric cardiac surgery. As of March 2016, 60% of participants in STS CHSD have agreed to publicly report their outcomes through the STS Public Reporting Online website (http://www.sts.org/quality-research-patient-safety/sts-public-reporting-online). Although several opportunities exist to improve our risk models, the current STS CHSD public reporting initiative provides the tools to report publicly, and with meaning and accuracy, the outcomes of congenital and pediatric cardiac surgery.