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The Society of Thoracic Surgeons Congenital Heart Surgery Database: 2018 Update on Research
OUTCOMES ANALYSIS, QUALITY IMPROVEMENT, AND PATIENT SAFETY
The Society of Thoracic Surgeons Congenital Heart Surgery Database: 2018 Update on Research Marshall L. Jacobs, MD, Jeffrey P. Jacobs, MD, Kevin D. Hill, MPH, Sean M. O’Brien, PhD, Sara K. Pasquali, MD, MHS, David Vener, MD, S. Ram Kumar, MD, PhD, Karen Chiswell, PhD, Robert H. Habib, PhD, David M. Shahian, MD, and Felix G. Fernandez, MD Johns Hopkins University School of Medicine, Baltimore, Maryland; Johns Hopkins All Children’s Heart Institute, Johns Hopkins All Children’s Hospital, St. Petersburg, Florida; Florida Hospital for Children, Orlando, Florida; Duke University, Durham, North Carolina; Duke Clinical Research Institute, Duke University, Durham, North Carolina; C.S. Mott Children’s Hospital, University of Michigan, Ann Arbor, Michigan; Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas; Children’s Hospital of Los Angeles, Keck University of Southern California School of Medicine, Los Angeles, California; The Society of Thoracic Surgeons Research Center, Chicago, Illinois; Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; and Emory University School of Medicine, Atlanta, Georgia
The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS CHSD) is the largest congenital and pediatric cardiac surgical clinical data registry in the world. The most recent biannual feedback report to participants includes analysis of data submitted from 125 hospitals, representing nearly all centers performing pediatric and congenital heart operations in the United States and Canada. In addition to serving as a platform for reporting of outcomes and for quality improvement, the database continues to be a primary data source for clinical research and for innovations related to quality measurement. Over the past year, several investigative teams reported analyses of data in the STS CHSD pertaining to various processes of care, including assessment of variation in specific practices and patient
characteristics across centers participating in the STS CHSD, and their associations with outcomes. Additional ongoing projects involve the development of new or refined metrics for quality measurement and reporting of outcomes and center level performance. To meet the needs of investigators, the STS Research Center and Workforce on Research Development has created multiple pathways through which investigators may propose and, ultimately, perform outcomes research projects based on STS CHSD data. This article reviews published outcomes research and quality improvement projects from the past year and describes ongoing research related to quality measurement.
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for CHD and is current with respect to contemporary perspectives in the broader context of outcomes reporting and quality measurement. Updates are engineered to maintain the utility of the “legacy” data that have previously been entered into the database using earlier versions. This strategy makes it possible for investigators to conduct research that is relevant with respect to the most contemporary challenges and trends in patient management and at the same time being informative with respect to the evolution of practice and trends in outcomes across eras. The last such updated version of the data collection form has been in use since January 2016, at which time implementation of version 3.3 of the STS CHSD took place [2]. The STS CHSD Task Force has nearly completed its work on the next update, with the expectation that the new version of the data collection form will be implemented beginning in January 2019. The Duke Clinical Research Institute (DCRI) serves as the data warehouse and analytic center for the STS CHSD and performs the biannual data analysis of all STS CHSD data collected during each preceding 4-year period, with
he Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (CHSD) has grown steadily to become the largest congenital and pediatric cardiac surgical clinical data registry in the world. More than 95% of centers in North America with programs for surgical management of pediatric and congenital heart disease (CHD) participate in the STS CHSD. Between 2002 and 2017, data pertaining to 434,647 operations have been entered, including 157,471 operations during the last 4-year data collection cycle of July 1, 2013, through June 30, 2017 [1]. Since 2010, the STS CHSD has included an anesthesia module that was developed in conjunction with the Congenital Cardiac Anesthesia Society. The STS CHSD data collection platform is thoroughly reviewed, assessed, and updated approximately every 3 years to ensure that data collection is relevant and up to date with respect to innovations in the practice of surgery
Address correspondence to Dr Marshall L. Jacobs, Division of Cardiac Surgery, The Johns Hopkins Hospital, Zayed 7107, 1800 Orleans St, Baltimore, MD 21287; email: [email protected].
Ó 2018 by The Society of Thoracic Surgeons Published by Elsevier Inc.
(Ann Thorac Surg 2018;106:654–63) Ó 2018 by The Society of Thoracic Surgeons
0003-4975/$36.00 https://doi.org/10.1016/j.athoracsur.2018.06.032
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analyses performed and feedback reports generated twice yearly. In the past year, DCRI and STS CHSD have changed to a year-round continuous submission process with two brief closed “lockdown” periods when data submissions will close and analysis reports will be generated based on the data currently submitted. Continuous data harvesting facilitates the generation of more frequent data quality reports, giving participant centers more opportunities and time to improve data quality by correcting any missing or conflicting data elements. The DCRI also collaborates with the STS Workforce on National Databases and the STS Quality Measurement Task Force (QMTF) to provide state-of-theart statistical and analytic expertise for the development of robust tools for quality measurement, including the current STS CHSD Mortality Risk Model for reporting of risk-adjusted outcomes [3, 4]. These metrics, including risk models, are key to the understanding and equitable reporting of outcomes and to facilitating quality improvement (QI).
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launched to allow analysis at investigators’ institutions of national-scale deidentified data from the database. The PUF program was designed primarily as an option for investigators to pose research questions, quickly obtain quality data, analyze these data themselves, receive feedback, and develop their efforts into abstracts and manuscripts [6]. Several “congenital” projects proposed to the PUF Research Program are presently underway. Proposals to the PUF Research Program may be submitted at any time and are continuously reviewed. The following is a summary of CHSD-based outcomes research articles published in peer-reviewed journals during the past year. These represent the work product of STS member investigators with support from the Congenital Heart Surgery Committee of the STS A&P Task Force, the STS CHSD Task Force, and the analytics team at DCRI. Brief synopses of these recently published articles are followed by additional reports describing ongoing research related to quality measurement.
STS CHSD Research Updates
“Effect of Obesity and Underweight Status on Outcomes of Congenital Heart Operations in Children, Adolescents, and Young Adults”
The STS CHSD is a suitable and accessible platform for clinical investigations broadly divided into two major categories: outcomes research and quality measurement. Outcomes research based on the STS CHSD mainly involves the investigation of associations between patient factors, procedural factors, processes of care, and surgical outcomes. Individual investigations may focus on specific diagnostic and procedural groups, age-defined cohorts, or the entire population of patients undergoing pediatric and congenital heart operations. Most studies are hypothesis driven and help to advance the understanding of factors affecting surgical outcomes. In addition, the STS CHSD is used for descriptive analyses aiming to elucidate patterns of practice and shed light on dissemination and adoption of new therapeutic modalities or on variation in care across participants. The latter, when significant, may point to target areas for QI initiatives. Most STS CHSD-related outcome studies continue to be initiated by database participants and their colleagues through submission of a proposal to the Congenital Heart Surgery Committee of the STS Access and Publications (A&P) Task Force. The STS A&P research program and its rules, processes, and procedures are described on the STS website. Submission forms for research proposals and data requests can be downloaded from the site [5]. Submission and evaluation of A&P proposals takes place twice yearly, in the spring and the fall. STS CHSD-based outcomes research can also be proposed through the STS Task Force on Funded Research, formerly the Task Force on Longitudinal FollowUp and Linked Registries, or the STS Participant User File (PUF) Research Program. The Task Force on Funded Research pathway is appropriate for evaluation of proposals that involve linkage of STS CHSD to other registries or sources of administrative data. These studies are usually funded by investigator institutions or other external funding sources. The STS PUF program was recently
This analysis by O’Byrne and associates [7] examined the association of body mass index (BMI) and perioperative outcome among children, adolescents, and young adults (overall range age, 10 to 35 years) undergoing congenital cardiac operations at 118 hospitals in the United States (US) between January 1, 2010, and December 31, 2015. To determine whether extreme BMI (either very high or very low) was associated with increased risk of adverse perioperative outcome, the investigators converted BMI to BMI percentile for age and sex, and assigned patients into strata defined by the US Centers for Disease Control and Prevention. Of 18,337 patients (118 centers), 16% were obese, 15% were overweight, 53% were normal weight, 7% were underweight, and 9% were severely underweight. Two primary outcomes were assessed. Operative mortality was based on the STS CHSD definition. A composite outcome was based on occurrence of any one or more of the following: operative mortality, major adverse event, wound infection, and prolonged length of stay (postoperative length of stay >14 days). The major adverse event end point was defined on the basis of previously described STS CHSD major complications [8], including temporary or permanent renal failure requiring dialysis, new neurologic deficit persisting at discharge, atrioventricular block or arrhythmia requiring permanent pacemaker, postoperative mechanical circulatory support, phrenic nerve injury, and unplanned reoperation or unplanned catheter intervention during the postoperative period. Wound infection was defined as any of the following: wound dehiscence, wound infection, including deep wound infection, mediastinitis, and superficial wound infection. Observed rates of operative mortality (p ¼ 0.04) and composite outcome (p < 0.0001) were higher in severely underweight and obese patients. Severely underweight BMI was associated with increased unplanned cardiac operation and reoperation for bleeding. Obesity was
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Fig 1. Results are shown for a linear spline model for the risk of a composite outcome by body mass index (BMI) percentile. The line of best fit (red line), knots (red circles), and 95% confidence intervals (black hashed line) are shown. For the composite outcome, the nonlinear association depicted is statistically significant. The odds of a composite outcome are increased at either extreme of BMI. Above the inflection point (a BMI percentile of 57%), increasing BMI increases the risk of a composite outcome. Below that same inflection point, decreasing BMI is also associated with increased risk of a composite outcome. Compared with a patient with normal weight (BMI percentile of 64%), the odds of a composite outcome are 1.53:1 for a severely underweight patient (BMI percentile of 5%) and 1.21:1 for an obese patient (BMI percentile of 95%). (Reproduced from O’Byrne and colleagues [7] with permission from the American Heart Association, Inc.)
associated with increased risk of wound infection. In multivariable analysis, the association between BMI and operative mortality was no longer significant. Obese (odds ratio [OR], 1.28; p ¼ 0.008), severely underweight (OR, 1.29; p < 0.0001), and underweight (OR, 1.39; p ¼ 0.002) patients were associated with increased risk of the composite outcome (Fig 1). The operations included in the study cohort evaluated by O’Byrne and associates included the full range of congenital heart operations performed in the specified age group (10 to 35 years). The authors observed that more than one-third of patients in the analytic cohort had a BMI associated with increased risk of an adverse perioperative outcome, underscoring the potential effect of interventions that address the nutritional status of patients with CHD. Previous studies have relied on data from administrative database sources to evaluate potential associations between obesity and diabetes mellitus and outcomes after cardiac operations in children. This was the first large, multiinstitutional study relying on clinical registry data and incorporating patient-level and procedure-level risk adjustment in multivariable logistic regression models to evaluate the associations between extremes of BMI and adverse outcomes among children, adolescents, and young adults undergoing congenital cardiac operations.
“Association of Surgeon Age and Experience with Congenital Heart Surgery Outcomes” For this study, Anderson and associates [9] used linked data from the American Medical Association Physician
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Masterfile and the STS-CHSD to examine associations between surgeon years since medical school and major morbidity/mortality for children undergoing cardiac operations. Surgeon age, years since completion of medical school, and years since terminal training were derived from the American Medical Association Physician Masterfile, a public registry of current and historic data on virtually all physicians training or practicing in the US. Investigators built a Pediatric Cardiothoracic Surgeon (PCS) Masterfile, including training and licensing characteristics for all US pediatric cardiothoracic surgeons. For surgeons graduating from non-US medical schools or training abroad, data were supplemented with self-reported data from The Cardiothoracic Surgery Network database [10]. The resulting PCS Masterfile was linked by National Provider Index Number to the STS-CHSD, and a limited data set, including only coded surgeon and patient identifiers, was abstracted. The analytic data set included all index cardiovascular operations in patients aged younger than 18 years undergoing a cardiac operation in the US, with or without cardiopulmonary bypass, at institutions contributing data to the STSCHSD between 2010 and 2014 that met criteria for inclusion in STS CHSD mortality analyses. Investigators identified 206 congenital heart surgeons from 91 centers performing 62,851 index operations (2010 to 2014). Median time from school was 25 years (range, 9 to 55 years). Average surgeon volumes were lowest among the youngest surgeons, peaked among mid-career and senior surgeons, and then tapered among the most senior. Early-career surgeons appeared to perform fewer STS– European Association for Cardio-Thoracic Surgery Congenital Heart Surgery (STAT) Mortality Category 5 and STS Morbidity Category 5 procedures. On average, very senior congenital heart surgeons operate on fewer of the highest risk patients than do their midcareer and senior colleagues. But, these very senior surgeons were more likely than their younger counterparts to perform operations on children who had previously undergone congenital heart operations (31.9% vs 27.4%, p < 0.0001). The primary objective of analysis was to examine associations between surgeon years since medical school and major morbidity/mortality for children undergoing cardiac operations. Logistic mixed-effects models were constructed to assess the effect of surgeon experience on outcomes, while adjusting for patient and procedural factors. Mortality was determined in accordance with the STS CHSD definition of operative mortality. Major morbidity was defined as one or more of six previously defined major complications. A major morbidity/mortality occurred in 11.5% of cases. In multivariable analyses, the odds of major morbidity/ mortality were similar for early-career (<15 years from medical school, w<40 years old), mid-career (15 to 24 years, w40 to 50 years old), and senior surgeons (25 to 35 years, w50 to 60 years old). Figure 2 displays the riskadjusted odds ratio (OR) of the composite outcome of
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“Shunt Failure-Risk Factors and Outcomes: An Analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database”
Fig 2. Restricted cubic splines are used to visually display the risk-adjusted odds ratio (OR) of the composite outcome of major morbidity or mortality as a function of surgeon years since medical school graduation, including upper and lower 95% confidence intervals (CIs). Vertical lines demarcate surgeon experience categories and a reference value of 10 years since medical school graduation. (Reproduced from Anderson and colleagues [9] with permission from the American Heart Association, Inc.)
major morbidity or mortality as a function of surgeon years since medical school graduation. The odds of major morbidity/mortality were approximately 25% higher for operations performed by very senior surgeons (35 to 55 years from school, w60 to 80 years old; n ¼ 9,044 cases). Results were driven by differences in morbidity. An extensive sensitivity analyses that adjusted for a variety of measures of team experience as well as for surgeon volume and center (team) volume showed these effects remained constant. Surgeon experience was not significantly associated with mortality when assessed as an independent outcome but was significantly associated with increased odds of major morbidity for patients operated on by surgeons with the most years of experience. The odds of major morbidity or mortality were approximately 25% higher for patients operated on by the very senior surgeons. The magnitude of this effect remained similar before and after adjusting for known confounders, including patient characteristics, center volumes, and surgeon team experience. Authors observed that patient outcomes for surgeons with the fewest years of experience were comparable to those of their mid-career and senior colleagues, within the context of existing referral and support practices. Based on these findings, authors suggested that contemporary approaches to training, referral, mentoring, surgical planning, and other support practices, or a combination of these, may contribute to the observed outcomes of junior congenital heart surgeons being comparable to those of more experienced colleagues. They suggested that understanding and disseminating these practices might benefit the medical community at large.
Shunt operations connecting the pulmonary arteries to a systemic artery or the systemic ventricle are common in the management of neonates and infants with CHD. Systemic-to-pulmonary shunt failure is a potentially catastrophic complication. Do and associates [11] analyzed data from the STS CHSD to describe the prevalence and evaluate risk factors for early shunt failure. Infants (aged <365 days) undergoing shunt operations (systemic artery-to-pulmonary artery or systemic ventricle-to-pulmonary artery) in 2010 to 2015 were included. Multivariable logistic regression was used to evaluate risk factors for in-hospital shunt failure. Model covariates included patient characteristics, preoperative factors, procedural factors, including shunt type, and center effects. Of 9,172 shunt operations performed on neonates and infants at 118 centers, in-hospital shunt failure occurred in 674 (7.3%). The event rate for in-hospital shunt failure varied across centers, with median of 6.2% (interquartile range: 3.3%, 10.6%). In multivariable analysis, risk factors for in-hospital shunt failure included lower weight at operation (OR, 1.35; p < 0.001), preoperative hypercoagulable state (OR, 2.47; p < 0.031), and the presence of any other STS-CHSD preoperative risk factors (OR, 1.24; p < 0.038). Shunt failure was less likely with a systemic ventricle-topulmonary artery shunt than a systemic artery-topulmonary artery shunt (OR, 0.65; p ¼ 0.020). Neither cardiopulmonary bypass nor single ventricle diagnosis was a risk factor for shunt failure. Results of the multivariable analysis were unchanged after all patients with systemic ventricle-to-pulmonary artery shunts (Norwood, Sano modification) were excluded, with the same covariates being identified as risk factors for in-hospital shunt failure. Patients with in-hospital shunt failure had significantly higher rates of operative mortality and major morbidity and a longer median postoperative length of stay among survivors (Table 1). After all patients with a systemic ventricle-to-pulmonary artery shunt were excluded from
Table 1. Outcomes: Shunt Failure and No Shunt Failure Groups (Unadjusted)a Shunt Failure (n ¼ 674)
No Shunt Failure (n ¼ 8,498)
1,122 (12.2) 215 (31.9) 1,159 (12.6) 215 (31.9) 3,071 (33.5) 569 (84.4) 23.0 45.0 (12.0, 42.0) (27.0, 84.0)
907 (10.7) 944 (11.1) 2,502 (29.4) 22.0 (12.0, 39.0)
Overall (N ¼ 9,172) Discharge mortality Operative mortality Morbidity composite Postoperative length of stay for hospital survivors, days a
Reproduced from Do and colleagues [11] with permission from The Society of Thoracic Surgeons. Data are presented as number (%) or as median (interquartile range).
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the analytic cohort, the comparison of secondary end points remained essentially unchanged. This was the largest study to date looking at shunt failure in infants, a complex and incompletely understood problem. The findings emphasize the scope and magnitude of the problem and help to clarify the characteristics of patients who may be at greatest risk. This information may help to identify individual patients that warrant expectant surveillance, enhanced pharmacologic management, or other strategies to reduce the risk of shunt failure. It also provides information that may be helpful in the design of future clinical trials or collaborative QI initiatives designed to reduce the cost in lives and resources that is associated with early shunt dysfunction.
“Associations Between Unplanned Cardiac Reinterventions and Outcomes After Pediatric Cardiac Operations” Unplanned cardiac reinterventions after pediatric cardiac operations may become necessary because of important residual anatomic defect(s), an incomplete preoperative diagnosis, or a failed therapeutic plan. A report in 2016 from the United Kingdom’s National Congenital Heart Disease Audit database found that 3.5% of patients underwent early reoperations, 15.8% of whom died [12]. A single-center study reported 11% of neonates underwent an early unplanned cardiac reintervention, the occurrence of which was a strong, independent risk factor for death [13]. Costello and associates [14] used the STS CHSD to determine the epidemiology of and risk factors for unplanned cardiac reinterventions during the same hospitalization as the index cardiac surgical operation and to explore associations between unplanned cardiac reinterventions and adverse outcomes. The study population included 84,404 patients who underwent an index cardiac operation at 117 institutions. Unplanned cardiac reinterventions were performed during the same hospitalization as the index operation in 4,743 patients (5.6%). Of these 4,743 patients, an unplanned cardiac surgical reoperation was performed in 2,804 (59%), an unplanned interventional cardiovascular catheterization procedure in 1,417 (30%), and both types of reintervention in 522 (11%). Of patients who underwent an unplanned cardiac reoperation, 89% underwent only one reoperation, 8.4% underwent two reoperations, 2.2% underwent three reoperations, and 0.6% underwent four or more reoperations. Rates of unplanned cardiac reinterventions were highest among neonates, followed by infants (Fig 3). Within the neonatal and infant subsets of patients, unplanned cardiac reinterventions were more common in patients who were smaller (Fig 4). By multivariable analysis, risk factors for unplanned cardiac reinterventions included nonwhite race, younger age, the presence of noncardiac anatomic abnormalities and genetic syndromes, prior cardiac operations, preoperative mechanical ventilation and other preoperative risk factors, and greater surgical complexity, according to stratification by STAT Mortality Category (adjusted p < 0.001 for all). Unplanned reintervention was a strong,
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Fig 3. Unplanned cardiac reintervention rates by age category. (Reproduced from Costello and colleagues [14] with permission from The Society of Thoracic Surgeons.) (Cath ¼ interventional catheterization; Reop ¼ unplanned cardiac reoperation.)
independent risk factor for operative mortality (adjusted OR, 5.3; 95% confidence interval, 4.8 to 5.8; p < 0.001) and longer postoperative length of stay (adjusted relative risk, 2.3; 95% confidence interval, 2.2 to 2.4; p < 0.001). Operative mortality occurred in 948 of 4,743 patients (20.0%) who underwent an unplanned cardiac reintervention and in 1,957 patients (2.5%) who did not (p < 0.0001; Fig 5). This study revealed that unplanned cardiac reinterventions were performed in greater than 5% of patients after pediatric cardiac operations. Reinterventions were
Fig 4. Rates of unplanned cardiac reinterventions by weight quintiles in (A) neonates and (B) infants. (Reproduced from Costello and colleagues [14] with permission from The Society of Thoracic Surgeons.)
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Fig 5. Operative mortality by performance of an unplanned cardiac reintervention (Reint). (Reproduced from Costello and colleagues [14] with permission from The Society of Thoracic Surgeons.) (Cath ¼ interventional catheterization; Reop ¼ unplanned cardiac reoperation.)
quite heterogeneous in nature, occurred in association with a broad spectrum of primary cardiac surgical procedures, and were strongly associated with adverse outcomes. Patients at increased risk may be identified preoperatively, presenting an opportunity for QI.
“Hybrid Palliation: Outcomes After the Comprehensive Stage 2 Procedure” The hybrid stage 1 procedure is an alternative initial palliative strategy for patients with single ventricle physiology and systemic ventricular outflow tract obstruction. It includes placement of bilateral pulmonary artery bands and frequently includes stent deployment to maintain patency of the arterial duct. Atrial septostomy may be undertaken at the time of hybrid stage 1 palliation or some time thereafter. For some patients, the hybrid stage 1 procedure serves as a “bridge” to a Norwood stage 1 procedure, a biventricular repair, or cardiac transplantation. But for many patients, the “comprehensive stage 2 procedure” (CS2) is the next planned surgical operation for these patients in anticipation of eventual completion of the Fontan circulation. The CS2 procedure consists of bilateral pulmonary artery band removal, with or without pulmonary artery patch angioplasty, patent ductus arteriosus stent removal with aortic arch reconstruction, amalgamation of the proximal main pulmonary trunk with the ascending aorta and reconstructed arch, atrial septectomy, and bidirectional superior cavopulmonary anastomosis. Cua and associates [15] undertook an analysis of STS CHSD data to describe CS2 outcomes and differences between survivors of CS2 (s-CS2) and nonsurvivors (nons-CS2). A review of the database revealed that from 2010 through 2016, 209 patients underwent CS2 as the index operation of their hospitalization at 49 centers. The most prevalent diagnosis was hypoplastic left heart syndrome (67.5%). There was a 17.0% incidence of premature birth and 8.0% incidence of associated noncardiac anomalies and syndromes. The incidence of an interventional catheterization procedure before the CS2 was
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9.1%. Age at operation was 181.4 62.0 days, weight was 6.3 1.2 kg, and cardiopulmonary bypass time was 250.0 76.1 minutes. Concomitant procedures performed at the time of CS2 included tricuspid valve procedures (2.4%), interventional catheterization procedures (4.8%), and extracorporeal membrane oxygenation (ECMO) cannulations (2.4%). Overall hospital length of stay was 25.1 27.4 days. Operative mortality was 12.4% (26 of 209). Postoperative major complications occurred in 56 patients (26.8%) and included unplanned postoperative interventions in 43 (20.6%), paralyzed diaphragm in 7 (3.4%), and postoperative ECMO in 17 (8.1%). Operative mortality was 71% (12 of 17) for patients who required postoperative ECMO support after CS2. Comparison of data pertaining to s-CS2 versus nons-CS2 revealed no significant differences in baseline demographics, overall prevalence of preoperative risk factors (53.9% vs 39.0%, p ¼ 0.15), or number of prior cardiothoracic operations (1.38 0.94 vs 1.17 0.66, p ¼ 0.28). Prevalence of other cardiac interventions before CS2 did not differ between the two groups. Cardiopulmonary bypass times, cross-clamp times, and circulatory arrest times were not different between non-CS2 and s-CS2. Frequency of concomitant tricuspid valve procedures was higher in the nons-CS2 patients. No other differences were found in concomitant procedures at the time of CS2. Evaluation of outcomes data revealed that nons-CS2 patients had a higher overall prevalence of the six major STS-CHSD postoperative complications than s-CS2 patients (53.9% vs 23.0%, respectively; p < 0.01). There was a higher prevalence of postoperative ECMO (46.2% vs 2.7%, p < 0.01) and renal failure requiring dialysis (7.7% vs 0.6%, respectively; p ¼ 0.04) in the nons-CS2 than in the s-CS2 group. No difference was observed in hospital length of stay between nons-CS2 and s-CS2 (20.2 20.2 days vs 25.7 28.3 days). CS2 procedures were performed in 22 additional patients, but not as the index operation, including instances in which hybrid stage 1 and CS2 took place during the same hospitalization. For these patients, who were not included in the primary analytic cohort, operative mortality was 63.6% (14 of 22). Notably, inspection of data reported in the Fall 2017 STS CHSD feedback report to participants [1] reveals that for the period July1, 2013, through June 30, 2017, there were 141 hybrid approach CS2 procedures, with operative mortality of 6.4% (10 patients). The observed diminution in operative mortality for CS2 operations across these time periods is unexplained. Whether differences in patient characteristics and preoperative factors may account for some of the difference remains at present, a matter of speculation.
Multicenter Quality Improvement Sternal Wound Infections in Pediatric Cardiac Surgery Patients Sternal wound infections (SWIs) in children undergoing cardiac operations are costly for patients, providers, and health care institutions. Numerous single-center projects
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to improve surveillance and prevent pediatric SWIs have been reported. A multicenter collaborative effort in Ohio developed a surgical site infection (SSI) prevention bundle. The collaborative program included pediatric cardiac surgical patients but excluded children who had delayed sternal closure (DSC) [16], a subgroup that is known to be at increased risk for SWIs. Woodward and associates [17] proposed and organized a nationwide multicenter QI project to evaluate the efficacy of a protocolized approach to reduce SWIs in pediatric cardiac surgery. An SWI Prevention Protocol was adopted by the 9 pediatric cardiac surgery programs that agreed to participate. The protocol interventions were based largely on the protocol used in a single-center QI project previously conducted by Woodward and colleagues [18] at the Pediatric Congenital Cardiac Center at University Health System in San Antonio, Texas. Implementation of the evidence-based protocol in that singlecenter project was associated with reduction of the SWI rate by 64% between year 1 and year 2 of the protocol. The multicenter QI project began after informational and training webinars had prepared the 9 programs for the project. Data were collected for pediatric cardiac surgical patients (age <18 years) who underwent operations from July 1, 2013, to June 30, 2015. Data collected by each participating site using its STS-compliant software were migrated to a program database created specifically for the QI project. This data set included all patients aged younger than 18 years who underwent a cardiac operation with cardiopulmonary bypass and sternotomy from July 1, 2011, to June 30, 2015, thus providing standardized and reliable “preprotocol data” as a baseline. Only the initial surgical case per patient per admission was counted. Ultimately, 9 children’s hospitals prospectively collected compliance data on 4,198 children (aged <18 years) who underwent sternotomy for a cardiac operation. In addition, programs migrated their “in-house registry” STS-CHSD data for 4,690 patients preprotocol and 4,143 patients postprotocol. The overall compliance with the protocol was 76.7% the first quarter of year 1 and 91.3% the final quarter of year 2 (Fig 6). Compliance with each of the interventions improved over the course of the 2-year project, with the exception of single-dose bolus preoperative antibiotic administration timing (0 to 60 minutes before incision), which remained more than 90% for the entire project (exclusive of vancomycin with administration timing 60 to 120 minutes before incision). Administration of any preoperative antibiotics within the prescribed timing window was associated with statistically significant decreased SWI rate. SWI occurred preprotocol in 90 of 4,690 children (1.9%) and in 64 of 4,143 children (1.5%) postprotocol, a 21% decrease (p ¼ 0.18). Overall, the days between infections preprotocol and postprotocol increased by 48%. Compliance data identified 657 patients (15%) who had DSC after the cardiac operation. The infection rate for the DSC group postprotocol was 5%, with 18 (5.7%) infections during year 1 and 14 (4.3%) in year 2, a 25% decrease (p ¼ 0.43). The median days between the operation and
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Fig 6. Percentage protocol compliance by year (Yr) and quarter (Qtr). (Reproduced from Woodward and colleagues [17] with permission from SAGE Publications.)
sternal closure was 3 days (mean, 4.3 days; range, 1 to 45 days). For DSC patients, there was a trend toward increased risk of SWI by 1.046 for each day the sternum remained open (p ¼ 0.067). A 49% difference in infection rates was documented for DSC patients who received preoperative antibiotics according to the protocol compared with those when the protocol was not followed: 4.6% versus 9.1%. QI projects are fundamentally different from clinical trials or other clinical research investigations, including those designed for assessment of clinical effectiveness. For this QI project, the protocol included several preoperative and postoperative elements aimed at reducing contamination of the skin and wound. The organizers intent was not to determine which of the elements made the most difference but, rather, to use a bundled approach as a method to reduce infections. One strength of this multicenter project was in the overall numbers of patients. But even with 4,690 patients, only 64 infections were reported over 2 years (SWI rate, 1.5%), too few to claim a statistically significant difference in the rate of infections after initiation of the protocol, despite observed decreases in rates of occurrence of wound infections at all levels (superficial, deep wound, and mediastinitis). The use of STS CHSD definitions allowed for data standardization across centers, and the use of each participating center’s in-house STS-compliant registry software made it possible to compare event rates and patient characteristics after implementation of the protocol against those in the 2-year period that preceded the beginning of the QI initiative.
Research Related to Quality Measurement “Refining The Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (CHSD) Mortality Risk Model with Enhanced Adjustment for Chromosomal Abnormalities, Syndromes, and Noncardiac Congenital Anatomic Abnormalities” Adjusting for case mix in congenital heart surgery is challenging due to the vast number of diagnoses,
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procedures, and potential risk factors, including chromosomal abnormalities (CAs), syndromes (Ss), noncardiac anatomic abnormalities (NCAAs), and comorbidities such as renal failure, acidosis, sepsis, and shock. Since 2015, the current STS CHSD Mortality Risk Model has been used in the analyses that produce the outcomes data in the feedback reports to participants [3, 4]. In addition to adjusting for procedural factors, this model adjusts for patient factors, including the binary presence or absence of a CA, S, or NCAA. Coefficients of the risk model are reestimated twice yearly, using data from the contemporary 4-year analytic window, to coincide with the production of each STS-CHSD participant feedback report. To further refine adjustment for case mix, a project to augment the STS CHSD Mortality Risk Model has been undertaken. The intent is to update the selection of covariates in the STS CHSD Mortality Risk Model to include a more detailed adjustment for CAs, Ss, and NCAAs. Adding more granular adjustment for individual CAs, Ss, and NCAAs is consistent with a hypothesis that associated mortality risk differs between individual conditions. To avoid double counting, Ss and CAs corresponding to the same condition were merged to a single condition code (eg, Edwards syndrome/trisomy 18). For Ss and CAs with at least 10 deaths in neonates and infants and at least 10 deaths in children and adults, ORs were estimated for the effect of the CA/S separately in neonates/infants and in children/adults. In addition to these condition/ age interactions, clinically relevant condition/age/procedure interactions were also explored. So for Down syndrome, the condition’s effect was estimated within separate subgroups based on age and specific procedure types, including atrioventricular canal repair and single ventricle palliation. Analysis included 107,062 operations at 100 centers (2010 to 2015). Overall observed operative mortality was 3,629 (3.4%). ORs were estimated for all individual Ss and CAs (and for specified CAs/Ss and age and procedural interactions). After estimating within-category heterogeneity by number of groups, five maximally homogeneous groups of CAs/Ss were created from 81 candidate CAs/Ss variables using Bayesian logistic regression modelling. A standard logistic regression model then incorporated indicator variables for the five categories of CAs/Ss, seven unique NCAAs, and all other covariates in the current STS CHSD Mortality Risk Model. The C statistic of the augmented STS CHSD Mortality Model in the development sample was 0.875. This investigation and the resultant refined risk model are representative of ongoing efforts by the STS QMTF and the STS CHSD Task Force to assure that adjustment for case mix in the outcomes reports of the STS CHSD is as complete as possible and that it is informed by contemporary empiric data.
Development of the First Congenital Heart Surgery Composite Quality Measure Current pediatric and congenital heart surgery quality measures focus on operative mortality. There is growing
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interest in the development of more comprehensive measures that incorporate additional outcome metrics and have the potential to reflect additional components of quality. The STS CHSD is the ideal data source and platform for the development of the first congenital heart surgery composite quality measure. For the past several years, a team of investigators led by Dr Sara Pasquali has embarked on a project to develop such a measure. The effort involves collaborations between the STS QMTF, the STS CHSD Task Force, Dr Pasquali and her colleagues at the University of Michigan C.S. Mott Children’s Hospital, and DCRI. Methodology and initial results of the project were presented by Dr Pasquali as the Richard E. Clark Memorial Paper for Congenital Heart Surgery at the STS 54th Annual Meeting in 2018. Individual measures considered for potential inclusion in the composite were reviewed within the context of the Donabedian triad and the Institute of Medicine quality domains. The final composite measure comprised two domains: (1) a mortality domain (operative mortality), and (2) a morbidity domain composed of two parts: (a) the 6 major complications endorsed by the STS and the Congenital Heart Surgeons’ Society plus cardiac arrest, and (b) postoperative length of stay. The composite measure was developed using the STS CHSD (2012 to 2015 data) and the current STS CHSD risk model for case-mix adjustment. Analysis was based on 78,425 operations at 100 centers. Mortality was weighted to have the greatest influence on the overall composite score, followed by major complications, and finally, postoperative length of stay (correlation with overall composite score of 0.87, 0.69, and 0.47, respectively). Reliability of the composite measure was high (0.73) and better than reliability for mortality alone (0.59). The overall distribution of centers across composite measure performance categories (defined by whether the 95% credible interval overlapped the STS average) was 75% (same as expected), 9% (worse than expected), and 16% (better than expected). The development of the first composite quality measure for pediatric and congenital cardiac surgery marks a major advance in the field of outcomes reporting, quality assessment, and performance measurement. The composite measure includes a mortality domain and morbidity domain and provides a more comprehensive view of quality than mortality alone. It also has greater ability to discriminate hospital performance through effectively increasing the number of end points. It is anticipated that in the future, the composite measure and its individual components will be included in STS-CHSD feedback reports to participating centers.
Leveraging Existing Resources to Improve Clinical Trials: A “Trial Within a Registry” of Perioperative Steroids to Improve Outcomes After Neonatal and Infant Cardiopulmonary Bypass Surgery Hill and colleagues [19] have developed a first-of-its-kind STS-CHSD Global Rank Endpoint (Table 2). The Global Rank approach involves ranking of outcomes in a composite measure commensurate with their perceived
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Table 2. Components of the Global Rank Endpoint Are All Captured Within The Society of Thoracic Surgeons Congenital Heart Surgery Databasea
Outcome
Assigned Rankb
Marginal Prevalence (N ¼ 11,408) No. (%)
Cumulative Prevalence (N ¼ 11,408) No. (%)
97 96 95
1,041 (9.1) 40 (0.4) 173 (1.5)
1,041 (9.1) 1,081 (9.5) 1,254 (11.0)
94
933 (8.2)
2,187 (19.2)
93
894 (7.8)
3,081 (27.0)
92
987 (8.7)
4,068 (35.7)
91 90–0
63 (0.6) 7,277 (63.8)
4,131 (36.2) 11,408 (100.0)
Operative mortality Heart transplant during hospitalization Renal failure with permanent dialysis, neurologic deficit persistent at discharge, or respiratory failure requiring tracheostomy Postoperative mechanical circulatory support or unplanned cardiac reoperation (exclusive of reoperation for bleeding) Reoperation for bleeding, delayed sternal closure, or postoperative unplanned interventional cardiac catheterization Postoperative cardiac arrest, multisystem organ failure, renal failure with temporary dialysis, or prolonged ventilator support (>7 days) Prolonged postoperative length of stay (>90 days, binary end point) Postoperative length of stay (assigned rank ¼ length of stay in days) a
Marginal and cumulative prevalence of the various outcomes are summarized. Reproduced from Hill and colleagues [19] with permission from the b American Heart Association, Inc. Patients were assigned ranks based on their highest ranking outcome.
clinical significance. Advantages of this approach include improved study power, the potential to combine binary and continuous outcome measures in a single composite, and the ability to better capture directionality of a treatment effect (eg, is a reoperation a bad outcome or an outcome that potentially prevents an operative mortality). The global rank approach improved study power compared with mortality alone (39% increased power) or a traditional composite end point using the same binary components as the Global Rank measure (þ3%). Power was further increased when hospital length of stay was incorporated as one of the rank outcomes (þ12%; Fig 7). Although the Global Rank Endpoint is applicable to outcomes analyses, in this instance, it was developed specifically for a planned registry-based randomized controlled trial. The STRESS trial (STeroids to REduce Systemic inflammation after infant heart Surgery trial) is a nested randomized controlled trial being conducted within the existing infrastructure of the STS CHSD. The trial is funded by the National Center for Advancing Translational Science (U01-TR-001803-01, NCT03229538 at ClinicalTrials.gov) and began enrolling in early 2018. Planned enrollment is for 1,200 infants, with 1:1 randomization to intraoperative methylprednisolone versus placebo, a strategy supported by the existence of clinical equipoise [20]. Currently, 15 sites are participating in the trial. There is a plan to increase participation to include up to 40 sites across the US and Canada. The bulk of data collection relies on the STS CHSD. The “trial within a registry” concept is a transformative approach that can reduce costs and expand the reach of randomized controlled trials, particularly in patients with rare diseases. Use of registry data helps to provide optimal trial design, provides quality control measures for data collection, and leverages mature infrastructure to compile, analyze, and disseminate data at a lower cost.
Conclusion The STS CHSD is a unique resource for research projects that are undertaken to further our understanding of associations between diagnoses, patient factors, treatment strategies, procedural factors, and outcomes. Summarized here are reports of STS CHSD-based research published during the past year and ongoing research efforts related to quality measurement. At all times, the STS QMTF is involved in the development, refinement, and validation of tools for quality measurement pertinent to pediatric and congenital heart surgery, working in collaboration with STS members and their colleagues and with the analytic and statistical teams at DCRI. Continuing growth of the STS CHSD, together with the numerous pathways for data access by qualified investigators, virtually ensures that the STS CHSD will
Fig 7. In simulations performed using The Society of Thoracic Surgeons data, the Global Rank Endpoint was compared with mortality alone and with an unranked composite end point consisting of the same binary outcome measures as the Global Rank Endpoint. Study power was increased by approximately 3% with ranking of the end points and by a further 12% when length of stay (LOS) was included in the Global Rank Score, regardless of the relative odds of a given outcome. (Reproduced from Hill and colleagues [19] with permission from the American Heart Association, Inc.)
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continually and increasingly be a resource for research that has the potential, ultimately, to benefit patients by providing evidence and insights that support meaningful progress in patient care. Dr S. Pasquali, Dr J.P. Jacobs, and coinvestigators received support from the National Heart, Lung, and Blood Institute (R01-HL122261). Dr K. Hill, Dr J.P. Jacobs, and Dr M. Jacobs and coinvestigators received support from the National Center for Advancing Translational Sciences (U01-TR-001803-01).
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8.
9. 10. 11.
References 1. Jacobs JP, Jacobs ML, Mavroudis C, Tchervenkov CI, Pasquali SK. Executive summary: The Society of Thoracic Surgeons Congenital Heart Surgery Database—twentyseventh harvest—(July 1, 2013 through June 30). Fall 2017 Harvest. The Society of Thoracic Surgeons (STS and Duke Clinical Research Institute (DCRI). Durham, NC: Duke University Medical Center; 2017. 2. The Society of Thoracic Surgeons Congenital Heart Database. Data collection form version 3.3. Available at https:// www.sts.org/sites/default/files/documents/CongenitalDCF_ v3_3_Annotated_Updated20160119.pdf. Accessed June 3, 2018. 3. O’Brien SM, Jacobs JP, Pasquali SK, et al. Society of Thoracic Surgeons Congenital Heart Surgery Database Mortality Risk Model: part 1-statistical methodology. Ann Thorac Surg 2015;100:1054–62. 4. Jacobs JP, O’Brien SM, Pasquali SK, et al. Society of Thoracic Surgeons Congenital Heart Surgery Database Mortality Risk Model: part 2-clinical application. Ann Thorac Surg 2015;100: 1063–8. 5. The Society of Thoracic Surgeons. Access & Publications. Access to data from the STS National Database. Available at https://www.sts.org/registries-research-center/sts-researchcenter/access-publications. Accessed June 3, 2018. 6. The Society of Thoracic Surgeons. Participant User File Research Program. Available at https://www.sts.org/ registries-research-center/sts-research-center/participantuser-file-research-program. Accessed June 3, 2018. 7. O’Byrne ML, Kim S, Hornik CP, et al. Effect of obesity and underweight status on perioperative outcomes of congenital heart operations in children, adolescents, and
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young adults: an analysis of data from The Society of Thoracic Surgeons Database. Circulation 2017;136:704–18. Jacobs ML, O’Brien SM, Jacobs JP, et al. An empirically based tool for analyzing morbidity associated with operations for congenital heart disease. J Thorac Cardiovasc Surg 2013;145: 1046–57. Anderson BR, Wallace AS, Hill KD, et al. Association of surgeon age and experience with congenital heart surgery outcomes. Circ Cardiovasc Qual Outcomes 2017;10:e003533. CTSNet (Cardiothoracic Surgery Network). Search for surgeons. Available at https://www.ctsnet.org/surgeons. Accessed June 3, 2018. Do N, Hill KD, Wallace AS, et al. Shunt failure—risk factors and outcomes: an analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database. Ann Thorac Surg 2018;105:857–64. Fiorentino F, Stickley J, Dorobantu D, et al. Early reoperations in a 5-year national cohort of pediatric patients with congenital heart disease. Ann Thorac Surg 2016;101:1522–9. Mazwi ML, Brown DW, Marshall AC, et al. Unplanned reinterventions are associated with postoperative mortality in neonates with critical congenital heart disease. J Thorac Cardiovasc Surg 2013;145:671–7. Costello JM, Mong e MC, Hill KD, et al. Associations between unplanned cardiac reinterventions and outcomes after pediatric cardiac operations. Ann Thorac Surg 2018;105: 1255–63. Cua CL, McConnell PI, Meza JM, et al. Hybrid palliation: outcomes after the comprehensive stage 2 procedure. Ann Thorac Surg 2018;105:1455–60. Toltzis P, O’Riordan M, Cunningham D, et al. A statewide collaborative to reduce pediatric surgical site infections. Pediatrics 2014;134:1174–80. Woodward C, Taylor R, Son M, et al. Multicenter quality improvement project to prevent sternal wound infections in pediatric cardiac surgery patients. World J Pediatr Congenit Heart Surg 2017;8:453–9. Woodward CS, Son M, Taylor R, Husain SA. Prevention of sternal wound infection in pediatric cardiac surgery: a protocolized approach. World J Pediatr Congenit Heart Surg 2012;3:463–6. Hill KD, O’Brien S, Baldwin HS, et al. Abstract 16573: Overcoming underpowering: simulation study to evaluate an STS Global Rank Endpoint for Trials in Congenital Heart Surgery. Circulation 2017;136:A16573. Hill KD, Kannankeril PJ. Perioperative corticosteroids in children undergoing congenital heart surgery: five decades of clinical equipoise. World J Pediatr Congenit Heart Surg 2018;9:294–6.
The Society of Thoracic Surgeons Congenital Heart Surgery Database: 2018 Update on Research Marshall L. Jacobs, MD, Jeffrey P. Jacobs, MD, Kevin D. Hill, MPH, Sean M. O’Brien, PhD, Sara K. Pasquali, MD, MHS, David Vener, MD, S. Ram Kumar, MD, PhD, Karen Chiswell, PhD, Robert H. Habib, PhD, David M. Shahian, MD, and Felix G. Fernandez, MD Johns Hopkins University School of Medicine, Baltimore, Maryland; Johns Hopkins All Children’s Heart Institute, Johns Hopkins All Children’s Hospital, St. Petersburg, Florida; Florida Hospital for Children, Orlando, Florida; Duke University, Durham, North Carolina; Duke Clinical Research Institute, Duke University, Durham, North Carolina; C.S. Mott Children’s Hospital, University of Michigan, Ann Arbor, Michigan; Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas; Children’s Hospital of Los Angeles, Keck University of Southern California School of Medicine, Los Angeles, California; The Society of Thoracic Surgeons Research Center, Chicago, Illinois; Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; and Emory University School of Medicine, Atlanta, Georgia
The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS CHSD) is the largest congenital and pediatric cardiac surgical clinical data registry in the world. The most recent biannual feedback report to participants includes analysis of data submitted from 125 hospitals, representing nearly all centers performing pediatric and congenital heart operations in the United States and Canada. In addition to serving as a platform for reporting of outcomes and for quality improvement, the database continues to be a primary data source for clinical research and for innovations related to quality measurement. Over the past year, several investigative teams reported analyses of data in the STS CHSD pertaining to various processes of care, including assessment of variation in specific practices and patient
characteristics across centers participating in the STS CHSD, and their associations with outcomes. Additional ongoing projects involve the development of new or refined metrics for quality measurement and reporting of outcomes and center level performance. To meet the needs of investigators, the STS Research Center and Workforce on Research Development has created multiple pathways through which investigators may propose and, ultimately, perform outcomes research projects based on STS CHSD data. This article reviews published outcomes research and quality improvement projects from the past year and describes ongoing research related to quality measurement.
T
for CHD and is current with respect to contemporary perspectives in the broader context of outcomes reporting and quality measurement. Updates are engineered to maintain the utility of the “legacy” data that have previously been entered into the database using earlier versions. This strategy makes it possible for investigators to conduct research that is relevant with respect to the most contemporary challenges and trends in patient management and at the same time being informative with respect to the evolution of practice and trends in outcomes across eras. The last such updated version of the data collection form has been in use since January 2016, at which time implementation of version 3.3 of the STS CHSD took place [2]. The STS CHSD Task Force has nearly completed its work on the next update, with the expectation that the new version of the data collection form will be implemented beginning in January 2019. The Duke Clinical Research Institute (DCRI) serves as the data warehouse and analytic center for the STS CHSD and performs the biannual data analysis of all STS CHSD data collected during each preceding 4-year period, with
he Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (CHSD) has grown steadily to become the largest congenital and pediatric cardiac surgical clinical data registry in the world. More than 95% of centers in North America with programs for surgical management of pediatric and congenital heart disease (CHD) participate in the STS CHSD. Between 2002 and 2017, data pertaining to 434,647 operations have been entered, including 157,471 operations during the last 4-year data collection cycle of July 1, 2013, through June 30, 2017 [1]. Since 2010, the STS CHSD has included an anesthesia module that was developed in conjunction with the Congenital Cardiac Anesthesia Society. The STS CHSD data collection platform is thoroughly reviewed, assessed, and updated approximately every 3 years to ensure that data collection is relevant and up to date with respect to innovations in the practice of surgery
Address correspondence to Dr Marshall L. Jacobs, Division of Cardiac Surgery, The Johns Hopkins Hospital, Zayed 7107, 1800 Orleans St, Baltimore, MD 21287; email: [email protected].
Ó 2018 by The Society of Thoracic Surgeons Published by Elsevier Inc.
(Ann Thorac Surg 2018;106:654–63) Ó 2018 by The Society of Thoracic Surgeons
0003-4975/$36.00 https://doi.org/10.1016/j.athoracsur.2018.06.032
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analyses performed and feedback reports generated twice yearly. In the past year, DCRI and STS CHSD have changed to a year-round continuous submission process with two brief closed “lockdown” periods when data submissions will close and analysis reports will be generated based on the data currently submitted. Continuous data harvesting facilitates the generation of more frequent data quality reports, giving participant centers more opportunities and time to improve data quality by correcting any missing or conflicting data elements. The DCRI also collaborates with the STS Workforce on National Databases and the STS Quality Measurement Task Force (QMTF) to provide state-of-theart statistical and analytic expertise for the development of robust tools for quality measurement, including the current STS CHSD Mortality Risk Model for reporting of risk-adjusted outcomes [3, 4]. These metrics, including risk models, are key to the understanding and equitable reporting of outcomes and to facilitating quality improvement (QI).
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launched to allow analysis at investigators’ institutions of national-scale deidentified data from the database. The PUF program was designed primarily as an option for investigators to pose research questions, quickly obtain quality data, analyze these data themselves, receive feedback, and develop their efforts into abstracts and manuscripts [6]. Several “congenital” projects proposed to the PUF Research Program are presently underway. Proposals to the PUF Research Program may be submitted at any time and are continuously reviewed. The following is a summary of CHSD-based outcomes research articles published in peer-reviewed journals during the past year. These represent the work product of STS member investigators with support from the Congenital Heart Surgery Committee of the STS A&P Task Force, the STS CHSD Task Force, and the analytics team at DCRI. Brief synopses of these recently published articles are followed by additional reports describing ongoing research related to quality measurement.
STS CHSD Research Updates
“Effect of Obesity and Underweight Status on Outcomes of Congenital Heart Operations in Children, Adolescents, and Young Adults”
The STS CHSD is a suitable and accessible platform for clinical investigations broadly divided into two major categories: outcomes research and quality measurement. Outcomes research based on the STS CHSD mainly involves the investigation of associations between patient factors, procedural factors, processes of care, and surgical outcomes. Individual investigations may focus on specific diagnostic and procedural groups, age-defined cohorts, or the entire population of patients undergoing pediatric and congenital heart operations. Most studies are hypothesis driven and help to advance the understanding of factors affecting surgical outcomes. In addition, the STS CHSD is used for descriptive analyses aiming to elucidate patterns of practice and shed light on dissemination and adoption of new therapeutic modalities or on variation in care across participants. The latter, when significant, may point to target areas for QI initiatives. Most STS CHSD-related outcome studies continue to be initiated by database participants and their colleagues through submission of a proposal to the Congenital Heart Surgery Committee of the STS Access and Publications (A&P) Task Force. The STS A&P research program and its rules, processes, and procedures are described on the STS website. Submission forms for research proposals and data requests can be downloaded from the site [5]. Submission and evaluation of A&P proposals takes place twice yearly, in the spring and the fall. STS CHSD-based outcomes research can also be proposed through the STS Task Force on Funded Research, formerly the Task Force on Longitudinal FollowUp and Linked Registries, or the STS Participant User File (PUF) Research Program. The Task Force on Funded Research pathway is appropriate for evaluation of proposals that involve linkage of STS CHSD to other registries or sources of administrative data. These studies are usually funded by investigator institutions or other external funding sources. The STS PUF program was recently
This analysis by O’Byrne and associates [7] examined the association of body mass index (BMI) and perioperative outcome among children, adolescents, and young adults (overall range age, 10 to 35 years) undergoing congenital cardiac operations at 118 hospitals in the United States (US) between January 1, 2010, and December 31, 2015. To determine whether extreme BMI (either very high or very low) was associated with increased risk of adverse perioperative outcome, the investigators converted BMI to BMI percentile for age and sex, and assigned patients into strata defined by the US Centers for Disease Control and Prevention. Of 18,337 patients (118 centers), 16% were obese, 15% were overweight, 53% were normal weight, 7% were underweight, and 9% were severely underweight. Two primary outcomes were assessed. Operative mortality was based on the STS CHSD definition. A composite outcome was based on occurrence of any one or more of the following: operative mortality, major adverse event, wound infection, and prolonged length of stay (postoperative length of stay >14 days). The major adverse event end point was defined on the basis of previously described STS CHSD major complications [8], including temporary or permanent renal failure requiring dialysis, new neurologic deficit persisting at discharge, atrioventricular block or arrhythmia requiring permanent pacemaker, postoperative mechanical circulatory support, phrenic nerve injury, and unplanned reoperation or unplanned catheter intervention during the postoperative period. Wound infection was defined as any of the following: wound dehiscence, wound infection, including deep wound infection, mediastinitis, and superficial wound infection. Observed rates of operative mortality (p ¼ 0.04) and composite outcome (p < 0.0001) were higher in severely underweight and obese patients. Severely underweight BMI was associated with increased unplanned cardiac operation and reoperation for bleeding. Obesity was
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Fig 1. Results are shown for a linear spline model for the risk of a composite outcome by body mass index (BMI) percentile. The line of best fit (red line), knots (red circles), and 95% confidence intervals (black hashed line) are shown. For the composite outcome, the nonlinear association depicted is statistically significant. The odds of a composite outcome are increased at either extreme of BMI. Above the inflection point (a BMI percentile of 57%), increasing BMI increases the risk of a composite outcome. Below that same inflection point, decreasing BMI is also associated with increased risk of a composite outcome. Compared with a patient with normal weight (BMI percentile of 64%), the odds of a composite outcome are 1.53:1 for a severely underweight patient (BMI percentile of 5%) and 1.21:1 for an obese patient (BMI percentile of 95%). (Reproduced from O’Byrne and colleagues [7] with permission from the American Heart Association, Inc.)
associated with increased risk of wound infection. In multivariable analysis, the association between BMI and operative mortality was no longer significant. Obese (odds ratio [OR], 1.28; p ¼ 0.008), severely underweight (OR, 1.29; p < 0.0001), and underweight (OR, 1.39; p ¼ 0.002) patients were associated with increased risk of the composite outcome (Fig 1). The operations included in the study cohort evaluated by O’Byrne and associates included the full range of congenital heart operations performed in the specified age group (10 to 35 years). The authors observed that more than one-third of patients in the analytic cohort had a BMI associated with increased risk of an adverse perioperative outcome, underscoring the potential effect of interventions that address the nutritional status of patients with CHD. Previous studies have relied on data from administrative database sources to evaluate potential associations between obesity and diabetes mellitus and outcomes after cardiac operations in children. This was the first large, multiinstitutional study relying on clinical registry data and incorporating patient-level and procedure-level risk adjustment in multivariable logistic regression models to evaluate the associations between extremes of BMI and adverse outcomes among children, adolescents, and young adults undergoing congenital cardiac operations.
“Association of Surgeon Age and Experience with Congenital Heart Surgery Outcomes” For this study, Anderson and associates [9] used linked data from the American Medical Association Physician
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Masterfile and the STS-CHSD to examine associations between surgeon years since medical school and major morbidity/mortality for children undergoing cardiac operations. Surgeon age, years since completion of medical school, and years since terminal training were derived from the American Medical Association Physician Masterfile, a public registry of current and historic data on virtually all physicians training or practicing in the US. Investigators built a Pediatric Cardiothoracic Surgeon (PCS) Masterfile, including training and licensing characteristics for all US pediatric cardiothoracic surgeons. For surgeons graduating from non-US medical schools or training abroad, data were supplemented with self-reported data from The Cardiothoracic Surgery Network database [10]. The resulting PCS Masterfile was linked by National Provider Index Number to the STS-CHSD, and a limited data set, including only coded surgeon and patient identifiers, was abstracted. The analytic data set included all index cardiovascular operations in patients aged younger than 18 years undergoing a cardiac operation in the US, with or without cardiopulmonary bypass, at institutions contributing data to the STSCHSD between 2010 and 2014 that met criteria for inclusion in STS CHSD mortality analyses. Investigators identified 206 congenital heart surgeons from 91 centers performing 62,851 index operations (2010 to 2014). Median time from school was 25 years (range, 9 to 55 years). Average surgeon volumes were lowest among the youngest surgeons, peaked among mid-career and senior surgeons, and then tapered among the most senior. Early-career surgeons appeared to perform fewer STS– European Association for Cardio-Thoracic Surgery Congenital Heart Surgery (STAT) Mortality Category 5 and STS Morbidity Category 5 procedures. On average, very senior congenital heart surgeons operate on fewer of the highest risk patients than do their midcareer and senior colleagues. But, these very senior surgeons were more likely than their younger counterparts to perform operations on children who had previously undergone congenital heart operations (31.9% vs 27.4%, p < 0.0001). The primary objective of analysis was to examine associations between surgeon years since medical school and major morbidity/mortality for children undergoing cardiac operations. Logistic mixed-effects models were constructed to assess the effect of surgeon experience on outcomes, while adjusting for patient and procedural factors. Mortality was determined in accordance with the STS CHSD definition of operative mortality. Major morbidity was defined as one or more of six previously defined major complications. A major morbidity/mortality occurred in 11.5% of cases. In multivariable analyses, the odds of major morbidity/ mortality were similar for early-career (<15 years from medical school, w<40 years old), mid-career (15 to 24 years, w40 to 50 years old), and senior surgeons (25 to 35 years, w50 to 60 years old). Figure 2 displays the riskadjusted odds ratio (OR) of the composite outcome of
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“Shunt Failure-Risk Factors and Outcomes: An Analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database”
Fig 2. Restricted cubic splines are used to visually display the risk-adjusted odds ratio (OR) of the composite outcome of major morbidity or mortality as a function of surgeon years since medical school graduation, including upper and lower 95% confidence intervals (CIs). Vertical lines demarcate surgeon experience categories and a reference value of 10 years since medical school graduation. (Reproduced from Anderson and colleagues [9] with permission from the American Heart Association, Inc.)
major morbidity or mortality as a function of surgeon years since medical school graduation. The odds of major morbidity/mortality were approximately 25% higher for operations performed by very senior surgeons (35 to 55 years from school, w60 to 80 years old; n ¼ 9,044 cases). Results were driven by differences in morbidity. An extensive sensitivity analyses that adjusted for a variety of measures of team experience as well as for surgeon volume and center (team) volume showed these effects remained constant. Surgeon experience was not significantly associated with mortality when assessed as an independent outcome but was significantly associated with increased odds of major morbidity for patients operated on by surgeons with the most years of experience. The odds of major morbidity or mortality were approximately 25% higher for patients operated on by the very senior surgeons. The magnitude of this effect remained similar before and after adjusting for known confounders, including patient characteristics, center volumes, and surgeon team experience. Authors observed that patient outcomes for surgeons with the fewest years of experience were comparable to those of their mid-career and senior colleagues, within the context of existing referral and support practices. Based on these findings, authors suggested that contemporary approaches to training, referral, mentoring, surgical planning, and other support practices, or a combination of these, may contribute to the observed outcomes of junior congenital heart surgeons being comparable to those of more experienced colleagues. They suggested that understanding and disseminating these practices might benefit the medical community at large.
Shunt operations connecting the pulmonary arteries to a systemic artery or the systemic ventricle are common in the management of neonates and infants with CHD. Systemic-to-pulmonary shunt failure is a potentially catastrophic complication. Do and associates [11] analyzed data from the STS CHSD to describe the prevalence and evaluate risk factors for early shunt failure. Infants (aged <365 days) undergoing shunt operations (systemic artery-to-pulmonary artery or systemic ventricle-to-pulmonary artery) in 2010 to 2015 were included. Multivariable logistic regression was used to evaluate risk factors for in-hospital shunt failure. Model covariates included patient characteristics, preoperative factors, procedural factors, including shunt type, and center effects. Of 9,172 shunt operations performed on neonates and infants at 118 centers, in-hospital shunt failure occurred in 674 (7.3%). The event rate for in-hospital shunt failure varied across centers, with median of 6.2% (interquartile range: 3.3%, 10.6%). In multivariable analysis, risk factors for in-hospital shunt failure included lower weight at operation (OR, 1.35; p < 0.001), preoperative hypercoagulable state (OR, 2.47; p < 0.031), and the presence of any other STS-CHSD preoperative risk factors (OR, 1.24; p < 0.038). Shunt failure was less likely with a systemic ventricle-topulmonary artery shunt than a systemic artery-topulmonary artery shunt (OR, 0.65; p ¼ 0.020). Neither cardiopulmonary bypass nor single ventricle diagnosis was a risk factor for shunt failure. Results of the multivariable analysis were unchanged after all patients with systemic ventricle-to-pulmonary artery shunts (Norwood, Sano modification) were excluded, with the same covariates being identified as risk factors for in-hospital shunt failure. Patients with in-hospital shunt failure had significantly higher rates of operative mortality and major morbidity and a longer median postoperative length of stay among survivors (Table 1). After all patients with a systemic ventricle-to-pulmonary artery shunt were excluded from
Table 1. Outcomes: Shunt Failure and No Shunt Failure Groups (Unadjusted)a Shunt Failure (n ¼ 674)
No Shunt Failure (n ¼ 8,498)
1,122 (12.2) 215 (31.9) 1,159 (12.6) 215 (31.9) 3,071 (33.5) 569 (84.4) 23.0 45.0 (12.0, 42.0) (27.0, 84.0)
907 (10.7) 944 (11.1) 2,502 (29.4) 22.0 (12.0, 39.0)
Overall (N ¼ 9,172) Discharge mortality Operative mortality Morbidity composite Postoperative length of stay for hospital survivors, days a
Reproduced from Do and colleagues [11] with permission from The Society of Thoracic Surgeons. Data are presented as number (%) or as median (interquartile range).
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the analytic cohort, the comparison of secondary end points remained essentially unchanged. This was the largest study to date looking at shunt failure in infants, a complex and incompletely understood problem. The findings emphasize the scope and magnitude of the problem and help to clarify the characteristics of patients who may be at greatest risk. This information may help to identify individual patients that warrant expectant surveillance, enhanced pharmacologic management, or other strategies to reduce the risk of shunt failure. It also provides information that may be helpful in the design of future clinical trials or collaborative QI initiatives designed to reduce the cost in lives and resources that is associated with early shunt dysfunction.
“Associations Between Unplanned Cardiac Reinterventions and Outcomes After Pediatric Cardiac Operations” Unplanned cardiac reinterventions after pediatric cardiac operations may become necessary because of important residual anatomic defect(s), an incomplete preoperative diagnosis, or a failed therapeutic plan. A report in 2016 from the United Kingdom’s National Congenital Heart Disease Audit database found that 3.5% of patients underwent early reoperations, 15.8% of whom died [12]. A single-center study reported 11% of neonates underwent an early unplanned cardiac reintervention, the occurrence of which was a strong, independent risk factor for death [13]. Costello and associates [14] used the STS CHSD to determine the epidemiology of and risk factors for unplanned cardiac reinterventions during the same hospitalization as the index cardiac surgical operation and to explore associations between unplanned cardiac reinterventions and adverse outcomes. The study population included 84,404 patients who underwent an index cardiac operation at 117 institutions. Unplanned cardiac reinterventions were performed during the same hospitalization as the index operation in 4,743 patients (5.6%). Of these 4,743 patients, an unplanned cardiac surgical reoperation was performed in 2,804 (59%), an unplanned interventional cardiovascular catheterization procedure in 1,417 (30%), and both types of reintervention in 522 (11%). Of patients who underwent an unplanned cardiac reoperation, 89% underwent only one reoperation, 8.4% underwent two reoperations, 2.2% underwent three reoperations, and 0.6% underwent four or more reoperations. Rates of unplanned cardiac reinterventions were highest among neonates, followed by infants (Fig 3). Within the neonatal and infant subsets of patients, unplanned cardiac reinterventions were more common in patients who were smaller (Fig 4). By multivariable analysis, risk factors for unplanned cardiac reinterventions included nonwhite race, younger age, the presence of noncardiac anatomic abnormalities and genetic syndromes, prior cardiac operations, preoperative mechanical ventilation and other preoperative risk factors, and greater surgical complexity, according to stratification by STAT Mortality Category (adjusted p < 0.001 for all). Unplanned reintervention was a strong,
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Fig 3. Unplanned cardiac reintervention rates by age category. (Reproduced from Costello and colleagues [14] with permission from The Society of Thoracic Surgeons.) (Cath ¼ interventional catheterization; Reop ¼ unplanned cardiac reoperation.)
independent risk factor for operative mortality (adjusted OR, 5.3; 95% confidence interval, 4.8 to 5.8; p < 0.001) and longer postoperative length of stay (adjusted relative risk, 2.3; 95% confidence interval, 2.2 to 2.4; p < 0.001). Operative mortality occurred in 948 of 4,743 patients (20.0%) who underwent an unplanned cardiac reintervention and in 1,957 patients (2.5%) who did not (p < 0.0001; Fig 5). This study revealed that unplanned cardiac reinterventions were performed in greater than 5% of patients after pediatric cardiac operations. Reinterventions were
Fig 4. Rates of unplanned cardiac reinterventions by weight quintiles in (A) neonates and (B) infants. (Reproduced from Costello and colleagues [14] with permission from The Society of Thoracic Surgeons.)
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Fig 5. Operative mortality by performance of an unplanned cardiac reintervention (Reint). (Reproduced from Costello and colleagues [14] with permission from The Society of Thoracic Surgeons.) (Cath ¼ interventional catheterization; Reop ¼ unplanned cardiac reoperation.)
quite heterogeneous in nature, occurred in association with a broad spectrum of primary cardiac surgical procedures, and were strongly associated with adverse outcomes. Patients at increased risk may be identified preoperatively, presenting an opportunity for QI.
“Hybrid Palliation: Outcomes After the Comprehensive Stage 2 Procedure” The hybrid stage 1 procedure is an alternative initial palliative strategy for patients with single ventricle physiology and systemic ventricular outflow tract obstruction. It includes placement of bilateral pulmonary artery bands and frequently includes stent deployment to maintain patency of the arterial duct. Atrial septostomy may be undertaken at the time of hybrid stage 1 palliation or some time thereafter. For some patients, the hybrid stage 1 procedure serves as a “bridge” to a Norwood stage 1 procedure, a biventricular repair, or cardiac transplantation. But for many patients, the “comprehensive stage 2 procedure” (CS2) is the next planned surgical operation for these patients in anticipation of eventual completion of the Fontan circulation. The CS2 procedure consists of bilateral pulmonary artery band removal, with or without pulmonary artery patch angioplasty, patent ductus arteriosus stent removal with aortic arch reconstruction, amalgamation of the proximal main pulmonary trunk with the ascending aorta and reconstructed arch, atrial septectomy, and bidirectional superior cavopulmonary anastomosis. Cua and associates [15] undertook an analysis of STS CHSD data to describe CS2 outcomes and differences between survivors of CS2 (s-CS2) and nonsurvivors (nons-CS2). A review of the database revealed that from 2010 through 2016, 209 patients underwent CS2 as the index operation of their hospitalization at 49 centers. The most prevalent diagnosis was hypoplastic left heart syndrome (67.5%). There was a 17.0% incidence of premature birth and 8.0% incidence of associated noncardiac anomalies and syndromes. The incidence of an interventional catheterization procedure before the CS2 was
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9.1%. Age at operation was 181.4 62.0 days, weight was 6.3 1.2 kg, and cardiopulmonary bypass time was 250.0 76.1 minutes. Concomitant procedures performed at the time of CS2 included tricuspid valve procedures (2.4%), interventional catheterization procedures (4.8%), and extracorporeal membrane oxygenation (ECMO) cannulations (2.4%). Overall hospital length of stay was 25.1 27.4 days. Operative mortality was 12.4% (26 of 209). Postoperative major complications occurred in 56 patients (26.8%) and included unplanned postoperative interventions in 43 (20.6%), paralyzed diaphragm in 7 (3.4%), and postoperative ECMO in 17 (8.1%). Operative mortality was 71% (12 of 17) for patients who required postoperative ECMO support after CS2. Comparison of data pertaining to s-CS2 versus nons-CS2 revealed no significant differences in baseline demographics, overall prevalence of preoperative risk factors (53.9% vs 39.0%, p ¼ 0.15), or number of prior cardiothoracic operations (1.38 0.94 vs 1.17 0.66, p ¼ 0.28). Prevalence of other cardiac interventions before CS2 did not differ between the two groups. Cardiopulmonary bypass times, cross-clamp times, and circulatory arrest times were not different between non-CS2 and s-CS2. Frequency of concomitant tricuspid valve procedures was higher in the nons-CS2 patients. No other differences were found in concomitant procedures at the time of CS2. Evaluation of outcomes data revealed that nons-CS2 patients had a higher overall prevalence of the six major STS-CHSD postoperative complications than s-CS2 patients (53.9% vs 23.0%, respectively; p < 0.01). There was a higher prevalence of postoperative ECMO (46.2% vs 2.7%, p < 0.01) and renal failure requiring dialysis (7.7% vs 0.6%, respectively; p ¼ 0.04) in the nons-CS2 than in the s-CS2 group. No difference was observed in hospital length of stay between nons-CS2 and s-CS2 (20.2 20.2 days vs 25.7 28.3 days). CS2 procedures were performed in 22 additional patients, but not as the index operation, including instances in which hybrid stage 1 and CS2 took place during the same hospitalization. For these patients, who were not included in the primary analytic cohort, operative mortality was 63.6% (14 of 22). Notably, inspection of data reported in the Fall 2017 STS CHSD feedback report to participants [1] reveals that for the period July1, 2013, through June 30, 2017, there were 141 hybrid approach CS2 procedures, with operative mortality of 6.4% (10 patients). The observed diminution in operative mortality for CS2 operations across these time periods is unexplained. Whether differences in patient characteristics and preoperative factors may account for some of the difference remains at present, a matter of speculation.
Multicenter Quality Improvement Sternal Wound Infections in Pediatric Cardiac Surgery Patients Sternal wound infections (SWIs) in children undergoing cardiac operations are costly for patients, providers, and health care institutions. Numerous single-center projects
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to improve surveillance and prevent pediatric SWIs have been reported. A multicenter collaborative effort in Ohio developed a surgical site infection (SSI) prevention bundle. The collaborative program included pediatric cardiac surgical patients but excluded children who had delayed sternal closure (DSC) [16], a subgroup that is known to be at increased risk for SWIs. Woodward and associates [17] proposed and organized a nationwide multicenter QI project to evaluate the efficacy of a protocolized approach to reduce SWIs in pediatric cardiac surgery. An SWI Prevention Protocol was adopted by the 9 pediatric cardiac surgery programs that agreed to participate. The protocol interventions were based largely on the protocol used in a single-center QI project previously conducted by Woodward and colleagues [18] at the Pediatric Congenital Cardiac Center at University Health System in San Antonio, Texas. Implementation of the evidence-based protocol in that singlecenter project was associated with reduction of the SWI rate by 64% between year 1 and year 2 of the protocol. The multicenter QI project began after informational and training webinars had prepared the 9 programs for the project. Data were collected for pediatric cardiac surgical patients (age <18 years) who underwent operations from July 1, 2013, to June 30, 2015. Data collected by each participating site using its STS-compliant software were migrated to a program database created specifically for the QI project. This data set included all patients aged younger than 18 years who underwent a cardiac operation with cardiopulmonary bypass and sternotomy from July 1, 2011, to June 30, 2015, thus providing standardized and reliable “preprotocol data” as a baseline. Only the initial surgical case per patient per admission was counted. Ultimately, 9 children’s hospitals prospectively collected compliance data on 4,198 children (aged <18 years) who underwent sternotomy for a cardiac operation. In addition, programs migrated their “in-house registry” STS-CHSD data for 4,690 patients preprotocol and 4,143 patients postprotocol. The overall compliance with the protocol was 76.7% the first quarter of year 1 and 91.3% the final quarter of year 2 (Fig 6). Compliance with each of the interventions improved over the course of the 2-year project, with the exception of single-dose bolus preoperative antibiotic administration timing (0 to 60 minutes before incision), which remained more than 90% for the entire project (exclusive of vancomycin with administration timing 60 to 120 minutes before incision). Administration of any preoperative antibiotics within the prescribed timing window was associated with statistically significant decreased SWI rate. SWI occurred preprotocol in 90 of 4,690 children (1.9%) and in 64 of 4,143 children (1.5%) postprotocol, a 21% decrease (p ¼ 0.18). Overall, the days between infections preprotocol and postprotocol increased by 48%. Compliance data identified 657 patients (15%) who had DSC after the cardiac operation. The infection rate for the DSC group postprotocol was 5%, with 18 (5.7%) infections during year 1 and 14 (4.3%) in year 2, a 25% decrease (p ¼ 0.43). The median days between the operation and
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Fig 6. Percentage protocol compliance by year (Yr) and quarter (Qtr). (Reproduced from Woodward and colleagues [17] with permission from SAGE Publications.)
sternal closure was 3 days (mean, 4.3 days; range, 1 to 45 days). For DSC patients, there was a trend toward increased risk of SWI by 1.046 for each day the sternum remained open (p ¼ 0.067). A 49% difference in infection rates was documented for DSC patients who received preoperative antibiotics according to the protocol compared with those when the protocol was not followed: 4.6% versus 9.1%. QI projects are fundamentally different from clinical trials or other clinical research investigations, including those designed for assessment of clinical effectiveness. For this QI project, the protocol included several preoperative and postoperative elements aimed at reducing contamination of the skin and wound. The organizers intent was not to determine which of the elements made the most difference but, rather, to use a bundled approach as a method to reduce infections. One strength of this multicenter project was in the overall numbers of patients. But even with 4,690 patients, only 64 infections were reported over 2 years (SWI rate, 1.5%), too few to claim a statistically significant difference in the rate of infections after initiation of the protocol, despite observed decreases in rates of occurrence of wound infections at all levels (superficial, deep wound, and mediastinitis). The use of STS CHSD definitions allowed for data standardization across centers, and the use of each participating center’s in-house STS-compliant registry software made it possible to compare event rates and patient characteristics after implementation of the protocol against those in the 2-year period that preceded the beginning of the QI initiative.
Research Related to Quality Measurement “Refining The Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (CHSD) Mortality Risk Model with Enhanced Adjustment for Chromosomal Abnormalities, Syndromes, and Noncardiac Congenital Anatomic Abnormalities” Adjusting for case mix in congenital heart surgery is challenging due to the vast number of diagnoses,
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procedures, and potential risk factors, including chromosomal abnormalities (CAs), syndromes (Ss), noncardiac anatomic abnormalities (NCAAs), and comorbidities such as renal failure, acidosis, sepsis, and shock. Since 2015, the current STS CHSD Mortality Risk Model has been used in the analyses that produce the outcomes data in the feedback reports to participants [3, 4]. In addition to adjusting for procedural factors, this model adjusts for patient factors, including the binary presence or absence of a CA, S, or NCAA. Coefficients of the risk model are reestimated twice yearly, using data from the contemporary 4-year analytic window, to coincide with the production of each STS-CHSD participant feedback report. To further refine adjustment for case mix, a project to augment the STS CHSD Mortality Risk Model has been undertaken. The intent is to update the selection of covariates in the STS CHSD Mortality Risk Model to include a more detailed adjustment for CAs, Ss, and NCAAs. Adding more granular adjustment for individual CAs, Ss, and NCAAs is consistent with a hypothesis that associated mortality risk differs between individual conditions. To avoid double counting, Ss and CAs corresponding to the same condition were merged to a single condition code (eg, Edwards syndrome/trisomy 18). For Ss and CAs with at least 10 deaths in neonates and infants and at least 10 deaths in children and adults, ORs were estimated for the effect of the CA/S separately in neonates/infants and in children/adults. In addition to these condition/ age interactions, clinically relevant condition/age/procedure interactions were also explored. So for Down syndrome, the condition’s effect was estimated within separate subgroups based on age and specific procedure types, including atrioventricular canal repair and single ventricle palliation. Analysis included 107,062 operations at 100 centers (2010 to 2015). Overall observed operative mortality was 3,629 (3.4%). ORs were estimated for all individual Ss and CAs (and for specified CAs/Ss and age and procedural interactions). After estimating within-category heterogeneity by number of groups, five maximally homogeneous groups of CAs/Ss were created from 81 candidate CAs/Ss variables using Bayesian logistic regression modelling. A standard logistic regression model then incorporated indicator variables for the five categories of CAs/Ss, seven unique NCAAs, and all other covariates in the current STS CHSD Mortality Risk Model. The C statistic of the augmented STS CHSD Mortality Model in the development sample was 0.875. This investigation and the resultant refined risk model are representative of ongoing efforts by the STS QMTF and the STS CHSD Task Force to assure that adjustment for case mix in the outcomes reports of the STS CHSD is as complete as possible and that it is informed by contemporary empiric data.
Development of the First Congenital Heart Surgery Composite Quality Measure Current pediatric and congenital heart surgery quality measures focus on operative mortality. There is growing
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interest in the development of more comprehensive measures that incorporate additional outcome metrics and have the potential to reflect additional components of quality. The STS CHSD is the ideal data source and platform for the development of the first congenital heart surgery composite quality measure. For the past several years, a team of investigators led by Dr Sara Pasquali has embarked on a project to develop such a measure. The effort involves collaborations between the STS QMTF, the STS CHSD Task Force, Dr Pasquali and her colleagues at the University of Michigan C.S. Mott Children’s Hospital, and DCRI. Methodology and initial results of the project were presented by Dr Pasquali as the Richard E. Clark Memorial Paper for Congenital Heart Surgery at the STS 54th Annual Meeting in 2018. Individual measures considered for potential inclusion in the composite were reviewed within the context of the Donabedian triad and the Institute of Medicine quality domains. The final composite measure comprised two domains: (1) a mortality domain (operative mortality), and (2) a morbidity domain composed of two parts: (a) the 6 major complications endorsed by the STS and the Congenital Heart Surgeons’ Society plus cardiac arrest, and (b) postoperative length of stay. The composite measure was developed using the STS CHSD (2012 to 2015 data) and the current STS CHSD risk model for case-mix adjustment. Analysis was based on 78,425 operations at 100 centers. Mortality was weighted to have the greatest influence on the overall composite score, followed by major complications, and finally, postoperative length of stay (correlation with overall composite score of 0.87, 0.69, and 0.47, respectively). Reliability of the composite measure was high (0.73) and better than reliability for mortality alone (0.59). The overall distribution of centers across composite measure performance categories (defined by whether the 95% credible interval overlapped the STS average) was 75% (same as expected), 9% (worse than expected), and 16% (better than expected). The development of the first composite quality measure for pediatric and congenital cardiac surgery marks a major advance in the field of outcomes reporting, quality assessment, and performance measurement. The composite measure includes a mortality domain and morbidity domain and provides a more comprehensive view of quality than mortality alone. It also has greater ability to discriminate hospital performance through effectively increasing the number of end points. It is anticipated that in the future, the composite measure and its individual components will be included in STS-CHSD feedback reports to participating centers.
Leveraging Existing Resources to Improve Clinical Trials: A “Trial Within a Registry” of Perioperative Steroids to Improve Outcomes After Neonatal and Infant Cardiopulmonary Bypass Surgery Hill and colleagues [19] have developed a first-of-its-kind STS-CHSD Global Rank Endpoint (Table 2). The Global Rank approach involves ranking of outcomes in a composite measure commensurate with their perceived
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Table 2. Components of the Global Rank Endpoint Are All Captured Within The Society of Thoracic Surgeons Congenital Heart Surgery Databasea
Outcome
Assigned Rankb
Marginal Prevalence (N ¼ 11,408) No. (%)
Cumulative Prevalence (N ¼ 11,408) No. (%)
97 96 95
1,041 (9.1) 40 (0.4) 173 (1.5)
1,041 (9.1) 1,081 (9.5) 1,254 (11.0)
94
933 (8.2)
2,187 (19.2)
93
894 (7.8)
3,081 (27.0)
92
987 (8.7)
4,068 (35.7)
91 90–0
63 (0.6) 7,277 (63.8)
4,131 (36.2) 11,408 (100.0)
Operative mortality Heart transplant during hospitalization Renal failure with permanent dialysis, neurologic deficit persistent at discharge, or respiratory failure requiring tracheostomy Postoperative mechanical circulatory support or unplanned cardiac reoperation (exclusive of reoperation for bleeding) Reoperation for bleeding, delayed sternal closure, or postoperative unplanned interventional cardiac catheterization Postoperative cardiac arrest, multisystem organ failure, renal failure with temporary dialysis, or prolonged ventilator support (>7 days) Prolonged postoperative length of stay (>90 days, binary end point) Postoperative length of stay (assigned rank ¼ length of stay in days) a
Marginal and cumulative prevalence of the various outcomes are summarized. Reproduced from Hill and colleagues [19] with permission from the b American Heart Association, Inc. Patients were assigned ranks based on their highest ranking outcome.
clinical significance. Advantages of this approach include improved study power, the potential to combine binary and continuous outcome measures in a single composite, and the ability to better capture directionality of a treatment effect (eg, is a reoperation a bad outcome or an outcome that potentially prevents an operative mortality). The global rank approach improved study power compared with mortality alone (39% increased power) or a traditional composite end point using the same binary components as the Global Rank measure (þ3%). Power was further increased when hospital length of stay was incorporated as one of the rank outcomes (þ12%; Fig 7). Although the Global Rank Endpoint is applicable to outcomes analyses, in this instance, it was developed specifically for a planned registry-based randomized controlled trial. The STRESS trial (STeroids to REduce Systemic inflammation after infant heart Surgery trial) is a nested randomized controlled trial being conducted within the existing infrastructure of the STS CHSD. The trial is funded by the National Center for Advancing Translational Science (U01-TR-001803-01, NCT03229538 at ClinicalTrials.gov) and began enrolling in early 2018. Planned enrollment is for 1,200 infants, with 1:1 randomization to intraoperative methylprednisolone versus placebo, a strategy supported by the existence of clinical equipoise [20]. Currently, 15 sites are participating in the trial. There is a plan to increase participation to include up to 40 sites across the US and Canada. The bulk of data collection relies on the STS CHSD. The “trial within a registry” concept is a transformative approach that can reduce costs and expand the reach of randomized controlled trials, particularly in patients with rare diseases. Use of registry data helps to provide optimal trial design, provides quality control measures for data collection, and leverages mature infrastructure to compile, analyze, and disseminate data at a lower cost.
Conclusion The STS CHSD is a unique resource for research projects that are undertaken to further our understanding of associations between diagnoses, patient factors, treatment strategies, procedural factors, and outcomes. Summarized here are reports of STS CHSD-based research published during the past year and ongoing research efforts related to quality measurement. At all times, the STS QMTF is involved in the development, refinement, and validation of tools for quality measurement pertinent to pediatric and congenital heart surgery, working in collaboration with STS members and their colleagues and with the analytic and statistical teams at DCRI. Continuing growth of the STS CHSD, together with the numerous pathways for data access by qualified investigators, virtually ensures that the STS CHSD will
Fig 7. In simulations performed using The Society of Thoracic Surgeons data, the Global Rank Endpoint was compared with mortality alone and with an unranked composite end point consisting of the same binary outcome measures as the Global Rank Endpoint. Study power was increased by approximately 3% with ranking of the end points and by a further 12% when length of stay (LOS) was included in the Global Rank Score, regardless of the relative odds of a given outcome. (Reproduced from Hill and colleagues [19] with permission from the American Heart Association, Inc.)
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continually and increasingly be a resource for research that has the potential, ultimately, to benefit patients by providing evidence and insights that support meaningful progress in patient care. Dr S. Pasquali, Dr J.P. Jacobs, and coinvestigators received support from the National Heart, Lung, and Blood Institute (R01-HL122261). Dr K. Hill, Dr J.P. Jacobs, and Dr M. Jacobs and coinvestigators received support from the National Center for Advancing Translational Sciences (U01-TR-001803-01).
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8.
9. 10. 11.
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