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

Clinical Risk Assessment and Prediction in Congenital Heart Disease Across the Lifespan: JACC Scientific Statement

Congenital heart disease (CHD) comprises a range of structural anomalies, each with a unique natural history, evolving treatment strategies, and distinct long-term consequences. Current prediction models are challenged by generalizability, limited validation, and questionable application to extended follow-up periods. In this JACC Scientific Statement, we tackle the difficulty of risk measurement across the lifespan. We appraise current and future risk measurement frameworks and describe domains of risk specific to CHD. Risk of adverse outcomes varies with age, sex, genetics, era, socioeconomic status, behavior, and comorbidities as they evolve through the lifespan and across care settings. Emerging technologies and approaches promise to improve risk assessment, but there is also need for large, longitudinal, representative, prospective CHD cohorts with multidimensional data and consensus-driven methodologies to provide insight into time-varying risk. Communication of risk, particularly with patients and their families, poses a separate and equally important challenge, and best practices are reviewed.

Textbook Outcome for Superior Cavopulmonary Connection: A Metric for Single Ventricle Heart Surgery

Background: To develop a more holistic measure of congenital heart center performance beyond mortality, we created a composite "textbook outcome" (TO) for the Glenn operation. We hypothesized that meeting TO would have a positive prognostic and financial impact. Methods: This was a single center retrospective study of patients undergoing superior cavopulmonary connection (bidirectional Glenn or Kawashima ± concomitant procedures) from 2005 to 2021. Textbook outcome was defined as freedom from operative mortality, reintervention, 30-day readmission, extracorporeal membrane oxygenation, major thrombotic complication, length of stay (LOS) >75th percentile (17d), and mechanical ventilation duration >75th percentile (2d). Multivariable logistic regression and Cox proportional hazards modeling were used. Results: Fifty-one percent (137/269) of patients met TO. Common reasons for TO failure were prolonged LOS (78/132, 59%) and ventilator duration (67/132, 51%). In multivariable analysis, higher weight [odds ratio, OR: 1.44 (95% confidence interval, CI: 1.15-1.84), P = .002] was a positive predictor of TO achievement while right ventricular dominance [OR 0.47 (0.27-0.81), P = .007] and higher preoperative pulmonary vascular resistance [OR 0.58 (0.40-0.82), P = .003] were negative predictors. After controlling for preoperative factors and excluding operative mortalities, TO achievement was independently associated with a decreased risk of death over long-term follow-up [hazard ratio: 0.50 (0.25-0.99), P = .049]. Textbook outcome achievement was also associated with lower direct cost of care [$137,626 (59,333-167,523) vs $262,299 (114,200-358,844), P < .0001]. Conclusion: Achievement of the Glenn TO is associated with long-term survival and lower costs and can be predicted by certain risk factors. As outcomes continue to improve within congenital heart surgery, operative mortality will become a less informative metric. Textbook outcome analysis may represent a more balanced measure of a successful outcome.

Center-Level Variation in Failure to Rescue After Pediatric Cardiac Surgery

BACKGROUND

Although failure to rescue (FTR) is increasingly recognized as a quality metric, studies in congenital cardiac surgery remain sparse. Within a national cohort of children undergoing cardiac operations, we characterized the presence of center-level variation in FTR and hypothesized a strong association with mortality but not complications.

METHODS

All children undergoing congenital cardiac operations were identified in the 2013 to 2019 Nationwide Readmissions Database. FTR was defined as in-hospital death after cardiac arrest, ventricular tachycardia/fibrillation, prolonged mechanical ventilation, pneumonia, stroke, venous thromboembolism, or sepsis, among other complications. Hierarchical models were used to generate hospital-specific, risk-adjusted rates of mortality, complications, and FTR. Centers in the highest decile of FTR were identified and compared with others.

RESULTS

Of an estimated 74,070 patients, 1.9% died before discharge, at least 1 perioperative complication developed in 43.0%, and 4.1% experienced FTR. After multilevel modeling, decreasing age, nonelective admission, and increasing operative complexity were associated with greater odds of FTR. Variations in overall mortality and FTR exhibited a strong, positive relationship (r = 0.97), whereas mortality and complications had a negligible association (r = -0.02). Compared with others, patients at centers with high rates of FTR had similar distributions of age, sex, chronic conditions, and operative complexity.

CONCLUSIONS

In the present study, center-level variations in mortality were more strongly explained by differences in FTR than complications. Our findings suggest the utility of FTR as a quality metric for congenital heart surgery, although further study is needed to develop a widely accepted definition and appropriate risk-adjustment models.

Contemporary Relationship Between Hospital Volume and Outcomes in Congenital Heart Surgery

BACKGROUND

Studies examining the volume-outcome relationship in congenital heart surgery (CHS) are more than a decade old. Since then, mortality has declined, and case-mix adjustment has evolved. We determined the current relationship between hospital CHS volume and outcomes.

METHODS

Patients aged ≤18 years undergoing index operations in The Society of Thoracic Surgeons-Congenital Heart Surgery Database (2017-2020) were included. Associations between annual hospital volume and case-mix-adjusted operative mortality, major complications, failure to rescue (FTR), and postoperative length of stay (PLOS) were assessed using Bayesian hierarchical models, overall, by The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) category, and for the Norwood procedure.

RESULTS

Across 101 centers (76,714 index operations), median annual volume was 144 operations/y. Operative mortality was 2.7%. Lower-volume hospitals had higher mortality, with an apparent transition zone at ∼190 operations/y (95% credible interval [CrI], 115-450 operations/y), below which a sustained uptick in the estimated odds of death occurred. Odds of death compared with a 450 operations/y reference were 50 operations/y (odds ratio [OR], 1.84; 95% CrI, 1.41-2.37), 100 operations/y (OR, 1.37; 95% CrI, 1.08-1.71), 200 operations/y (OR, 0.92; 95% CrI, 0.1-1.18), 300 operations/y (OR, 0.89; 95% CrI, 0.76-1.04). The volume-outcome effect was more apparent for STAT 4 to 5 than STAT 1 to 3 operations. In the overall cohort, PLOS and complications were similar across hospital volumes, whereas FTR rates were higher at lower-volume hospitals. Lower-volume hospitals had worse outcomes after the Norwood procedure, most notably mortality and FTR.

CONCLUSIONS

Hospital volume is associated with mortality and FTR after CHS. The relationship is strongest for high-risk operations. These data can inform ongoing initiatives to improve CHS care.

Contemporary Patterns of Care in Tetralogy of Fallot: Analysis of The Society of Thoracic Surgeons Data

BACKGROUND

Against the background of earlier studies, recent patterns in surgical management of tetralogy of Fallot (TOF) were assessed.

METHODS

A retrospective review of The Society of Thoracic Surgeons (STS) Congenital Database (2010-2020) was performed on patients aged <18 years with TOF or pulmonary stenosis and primary procedure TOF surgical repair or palliation. Procedural frequencies were examined by epoch. Demographics, clinical variables, and outcomes were compared between the initial palliation and primary repair groups. Among those operated on at 0 to 60 days of age, variation in palliation rates across hospitals was assessed.

RESULTS

The 12,157 operations included 11,307 repairs (93.0%) and 850 palliations (7.0%); 68.5% of all palliations were modified Blalock-Taussig-Thomas shunts. Of 1105 operations on neonates, 45.4% (502) were palliations. Among neonates, palliations declined from 49.0% (331 of 675) in epoch 1 (2010-2015) to 39.8% (171 of 430) in epoch 2 (2016-2020; P = .0026). Overall, the most prevalent repair technique (5196 of 11,307; 46.0%) was ventriculotomy with transanular patch, which was also used in 520 of 894 (58.2%) of repairs after previous cardiac operations. Patients undergoing initial palliation demonstrated more preoperative STS risk factors (50.1% vs 24.3% respectively; P < .0001) and more major morbidity and mortality than patients undergoing primary repair (21.2% vs 7.46%; P < .0001). In the 0- to 60-day age group, risk factor-adjusted palliation rates across centers varied considerably, with 32 of 99 centers performing significantly more or significantly fewer palliations than predicted on the basis of their case mix.

CONCLUSIONS

Surgical palliation rates have decreased across all age groups despite increasing prevalence of risk factors. Ventriculotomy with transanular patch remains the most prevalent repair type. The considerable center-level variation in rates of palliation was not completely explained by case mix.

Textbook outcome for the Norwood operation-an informative quality metric in congenital heart surgery

Objectives

To develop a more holistic measure of center performance than operative mortality, we created a composite "textbook outcome" for the Norwood operation using several postoperative end points. We hypothesized that achieving the textbook outcome would have a positive prognostic and financial impact.

Methods

This was a single-center retrospective study of primary Norwood operations from 2005 to 2021. Through interdisciplinary clinician consensus, textbook outcome was defined as freedom from operative mortality, open or catheter-based reintervention, 30-day readmission, extracorporeal membrane oxygenation, cardiac arrest, reintubation, length of stay >75%ile from Society of Thoracic Surgeons data report (66 days), and mechanical ventilation duration >75%ile (10 days). Multivariable logistic regression and Cox proportional hazards modeling were used to determine predictive factors for textbook outcome achievement and association of the outcome with long-term survival, respectively.

Results

Overall, 30% (58/196) of patients met the textbook outcome. Common reasons for failure to attain textbook outcome were prolonged ventilation (68/138, 49%) and reintubation (63/138, 46%). In multivariable analysis, greater weight (odds ratio [OR], 2.11; 95% confidence interval [CI], 1.17-3.95; P = .02) was associated with achieving the textbook outcome whereas preoperative shock (OR, 0.36; 95% CI, 0.13-0.87; P = .03) and longer bypass time (OR, 0.99; 95% CI, 0.98-1.00; P = .002) were negatively associated. Patients who met the outcome incurred fewer hospital costs ($152,430 [141,798-177,983] vs $269,070 [212,451-372,693], P < .001), and after adjusting for patient factors, achieving textbook outcome was independently associated with decreased risk of all-cause mortality (hazard ratio, 0.45; 95% CI, 0.22-0.89; P = .02).

Conclusions

Outcomes continue to improve within congenital heart surgery, making operative mortality a less-sensitive metric. The Norwood textbook outcome may represent a balanced measure of a successful episode of care.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Characterization of "ICU-30": A Binary Composite Outcome for Neonates With Critical Congenital Heart Disease

Background

Neonates with heart disease requiring cardiopulmonary bypass surgery are at high risk for mortality and morbidity. As it is rare, short‐term mortality is difficult to use as a primary outcome for clinical studies. We proposed “ICU‐30” as a binary composite “poor” outcome consisting of: (1) mortality within 30 days, (2) intensive care unit (ICU) admission ≥30 days, or (3) ICU readmission before day 30. To measure the utility of this composite, we assessed its prognostic properties for 6‐ and 12‐month mortality.

Methods and Results

This was a retrospective single‐center cohort study of neonates requiring cardiopulmonary bypass between 2013 and 2020. Mortality among patients with and without the ICU‐30 outcome was compared using log‐rank tests and Cox regression. Areas under the receiver operating characteristic curves assessed the ability of the composite to predict 12‐month mortality. In 887 neonates, 232 (26.2%) experienced the ICU‐30 outcome, with more prolonged ICU stays and readmissions (both ≥9%) than 30‐day mortality (4.2%). ICU‐30 was associated with higher rates of 6‐ and 12‐month mortality (log‐rank P<0.001) and predicted 12‐month mortality with area under the receiver operating characteristic of 0.81 (95% CI, 0.77–0.85). In 30‐day survivors, both prolonged ICU stay (hazard ratio, 12.3; 95% CI, 6.70–22.7; P<0.001) and ICU readmission (hazard ratio, 2.99; 95% CI, 1.17–7.63; P=0.02) were associated with 12‐month mortality.

Conclusions

ICU‐30, a composite outcome of mortality, ICU length of stay, or ICU readmission by 30 days was associated with 6‐ and 12‐month mortality in neonates requiring cardiopulmonary bypass. ICU‐30 is captured in routine data collection and appears to be a valid binary patient‐centered outcome.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Comparison of Postoperative, In-Hospital Outcomes After Complete Repair of Tetralogy of Fallot Between 22q11.2 Deletion Syndrome and Trisomy 21

22q11.2 deletion syndrome (22q11) and trisomy 21 (T21) are frequently associated with tetralogy of Fallot (TOF). We hypothesized that there are differences in postoperative length of stay (LOS) and occurrence of postoperative interventions after complete repair of TOF when comparing children with 22q11 to those with T21. Using the Pediatric Health Information System, we performed a retrospective cohort study of patients who underwent complete repair of TOF from 2004 to 2019. Three groups were identified: 22q11, T21, and controls (those without a coded genetic syndrome). Outcomes were postoperative LOS and composite occurrence (yes/no) of at least one postoperative intervention. Bivariate and multivariate comparisons were made among groups; odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using the control group as the comparator. There were 6924 subjects (n = 493 22q11, n = 455 T21, n = 5976 controls). In bivariate analysis, 22q11 was associated with a longer LOS compared to T21 (OR 2.37 [2.16, 2.60] vs. 1.25 [1.12, 1.39], p < 0.001), and 22q11 more often underwent postoperative intervention (OR 3.42 [CI 2.56, 4.57] vs. 1.38 [CI 0.91, 2.11]; p < 0.001). In multivariate analysis, 22q11 was also associated with longer LOS (adjusted OR 1.35 [1.26, 1.44] vs. 1.12 [1.04, 1.20]; p < 0.001), but there was no difference in the adjusted odds of postoperative intervention. Children with 22q11 are more likely to experience adverse outcomes after repair of TOF compared to those with T21; the differences are most pronounced for LOS.

Evolving Cost-Quality Relationship in Pediatric Heart Surgery

BACKGROUND

For the >40,000 US children undergoing congenital heart surgery annually, the relationship between hospital quality and costs remains unclear. Prior studies report conflicting results and clinical outcomes have continued to improve over time. We examined a large contemporary cohort, aiming to better inform ongoing initiatives seeking to optimize healthcare value in this population.

METHODS

Clinical information (Society of Thoracic Surgeons Congenital Database) was merged with standardized cost data (Pediatric Health Information Systems) for children undergoing heart surgery from 2010-2015. In-hospital cost variability was analyzed using Bayesian hierarchical models adjusted for case-mix. Quality metrics examined included in-hospital mortality, post-operative complications, length of stay (PLOS), and a composite.

RESULTS

Overall 32 hospitals (n=45,315 patients) were included. Median adjusted cost/case varied across hospitals from $67,700 to $51,200 in the high vs. low cost tertile (ratio 1.32, 95% credible interval 1.29-1.35), and all quality metrics also varied across hospitals. Across cost tertiles there were no significant differences in the quality metrics examined, with the exception of PLOS. The PLOS findings were driven by high-risk STAT 4-5 cases [adjusted median LOS 16.8 vs. 14.9 days in high vs. low cost tertile (ratio 1.13, 1.05-1.24)], and ICU PLOS.

CONCLUSIONS

Contemporary congenital heart surgery costs vary across hospitals but were not associated with most quality metrics examined, highlighting that performance in one area does not necessarily convey to others. Cost variability was associated with PLOS, particularly related to ICU PLOS and high-risk cases. Care processes influencing PLOS may provide targets for value-based initiatives in this population.

The Society of Thoracic Surgeons Congenital Heart Surgery Database: 2020 Update on Outcomes and Research

The Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (CHSD) continues to be a highly regarded, comprehensive clinical outcomes database that captures more than 90% of all congenital heart surgery cases in the United States and has more than 90% of all congenital heart surgery centers as participants. This report includes aggregate information on clinical outcomes evaluated at the aggregate and The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) category levels for the period July 1, 2015, through June 30, 2019. It also includes the published research activities that use data from the STS CHSD. Also included is information on the STS CHSD auditing function, a summary of the significant revisions to the data, which is collected on each patient, and an update on efforts to update the risk-adjustment methods for evaluation of the outcomes.

National Variation in Congenital Heart Surgery Outcomes

BACKGROUND

Optimal strategies to improve national congenital heart surgery outcomes and reduce variability across hospitals remain unclear. Many policy and quality improvement efforts have focused primarily on higher-risk patients and mortality alone. Improving our understanding of both morbidity and mortality and current variation across the spectrum of complexity would better inform future efforts.

METHODS

Hospitals participating in the Society of Thoracic Surgeons Congenital Heart Surgery Database (2014-2017) were included. Case mix-adjusted operative mortality, major complications, and postoperative length of stay were evaluated using Bayesian models. Hospital variation was quantified by the interdecile ratio (IDR, upper versus lower 10%) and 95% credible intervals (CrIs). Stratified analyses were performed by risk group (Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery [STAT] category) and simulations evaluated the potential impact of reductions in variation.

RESULTS

A total of 102 hospitals (n=84 407) were included, representing ≈85% of US congenital heart programs. STAT category 1 to 3 (lower risk) operations comprised 74% of cases. All outcomes varied significantly across hospitals: adjusted mortality by 3-fold (upper versus lower decile 5.0% versus 1.6%, IDR 3.1 [95% CrI 2.5-3.7]), mean length of stay by 1.8-fold (19.2 versus 10.5 days, IDR 1.8 [95% CrI 1.8-1.9]), and major complications by >3-fold (23.5% versus 7.0%, IDR 3.4 [95% CrI 3.0-3.8]). The degree of variation was similar or greater for low- versus high-risk cases across outcomes, eg, ≈3-fold mortality variation across hospitals for STAT 1 to 3 (IDR 3.0 [95% CrI 2.1-4.2]) and STAT 4 or 5 (IDR 3.1 [95% CrI 2.4-3.9]) cases. High-volume hospitals had less variability across outcomes and risk categories. Simulations suggested potential reductions in deaths (n=282), major complications (n=1539), and length of stay (101 183 days) over the 4-year study period if all hospitals were to perform at the current median or better, with 37% to 60% of the improvement related to the STAT 1 to 3 (lower risk) group across outcomes.

CONCLUSIONS

We demonstrate significant hospital variation in morbidity and mortality after congenital heart surgery. Contrary to traditional thinking, a substantial portion of potential improvements that could be realized on a national scale were related to variability among lower-risk cases. These findings suggest modifications to our current approaches to optimize care and outcomes in this population are needed.

Improvement in Pediatric Cardiac Surgical Outcomes Through Interhospital Collaboration

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Society of Thoracic Surgeons National Database 2019 Annual Report

The Society of Thoracic Surgeons (STS) National Database was established in 1989 as an initiative for quality improvement and patient safety for cardiothoracic surgery. The STS National Database has 4 components, each focusing on a distinct discipline-Adult Cardiac Surgery, General Thoracic Surgery, Congenital Heart Surgery, and mechanical circulatory support with the STS Interagency Registry for Mechanical Circulatory Support (Intermacs)/Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) Database. In December 2015, The Annals of Thoracic Surgery began publishing a monthly series of scholarly articles on outcomes analysis, quality improvement, and patient safety. This article provides the fourth annual summary of the status of the STS National Database.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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