Pathology of explanted pediatric hearts: An 11-year study. Population characteristics and implications for outcomes

BACKGROUND

As more pediatric patients become candidates for heart transplantation (HT), understanding pathological predictors of outcome and the accuracy of the pretransplantation evaluation are important to optimize utilization of scarce donor organs and improve outcomes. The authors aimed to investigate explanted heart specimens to identify pathologic predictors that may affect cardiac allograft survival after HT.

METHODS

Explanted pediatric hearts obtained over an 11-year period were analyzed to understand the patient demographics, indications for transplant, and the clinical-pathological factors.

RESULTS

In this study, 149 explanted hearts, 46% congenital heart defects (CHD), were studied. CHD patients were younger and mean pulmonary artery pressure and resistance were significantly lower than in cardiomyopathy patients. Twenty-one died or underwent retransplantation (14.1%). Survival was significantly higher in the cardiomyopathy group at all follow-up intervals. There were more deaths and the 1-, 5- and 7-year survival was lower in patients ≤10 years of age at HT. Early rejection was significantly higher in CHD patients exposed to homograft tissue, but not late rejection. Mortality/retransplantation rate was significantly higher and allograft survival lower in CHD hearts with excessive fibrosis of one or both ventricles. Anatomic diagnosis at pathologic examination differed from the clinical diagnosis in eight cases.

CONCLUSIONS

Survival was better for the cardiomyopathy group and patients >10 years at HT. Prior homograft use was associated with a higher prevalence of early rejection. Ventricular fibrosis (of explant) was a strong predictor of outcome in the CHD group. We presented several pathologic findings in explanted pediatric hearts.

Genome Sequencing is Critical for Forecasting Outcomes following Congenital Cardiac Surgery

While genome sequencing has transformed medicine by elucidating the genetic underpinnings of both rare and common complex disorders, its utility to predict clinical outcomes remains understudied. Here, we used artificial intelligence (AI) technologies to explore the predictive value of genome sequencing in forecasting clinical outcomes following surgery for congenital heart defects (CHD). We report results for a cohort of 2,253 CHD patients from the Pediatric Cardiac Genomics Consortium with a broad range of complex heart defects, pre- and post-operative clinical variables and exome sequencing. Damaging genotypes in chromatin-modifying and cilia-related genes were associated with an elevated risk of adverse post-operative outcomes, including mortality, cardiac arrest and prolonged mechanical ventilation. The impact of damaging genotypes was further amplified in the context of specific CHD phenotypes, surgical complexity and extra-cardiac anomalies. The absence of a damaging genotype in chromatin-modifying and cilia-related genes was also informative, reducing the risk for adverse postoperative outcomes. Thus, genome sequencing enriches the ability to forecast outcomes following congenital cardiac surgery.

The Society of Thoracic Surgeons Congenital Heart Surgery Database: 2023 Update on Outcomes and Research

The Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (CHSD) continues to be the most comprehensive database of congenital and pediatric cardiothoracic surgical procedures in the world and contains information on 664,210 operations as of June 30, 2023. The 35th harvest of the STS CHSD data was undertaken in Spring 2023, spanning the 4-year period January 1, 2019, through December 31, 2022, and included 144,919 operations performed at 114 participating sites in North America. The harvest analysis was successfully executed by the STS Research and Analytic Center. The overall unadjusted mortality rate was 2.68% and has remained stable over the 4 years included in the current harvest window. Mortality is highest in neonates (7.4%) and lowest in children (1.1%). As in prior analyses, observed mortality and postoperative length of stay in the database increase with an increase in STS-European Association for Cardio-Thoracic Surgery (STAT) Congenital Heart Surgery Mortality Categories. This quality report summarizes contemporary outcomes, provides the odds ratios for the CHSD risk model variables based on this analysis, and describes on-going efforts to improve data collection and augment analytical approaches. Lastly, 5 research publications completed in the last year using data from the CHSD are also summarized.

Association Between Past and Present Operative Mortality in Congenital Heart Surgery

BACKGROUND

Mortality following congenital heart surgery is an important metric across benchmarking, quality, and reporting initiatives. All rely on estimates from prior years, and it is unclear how well these reflect current outcomes.

METHODS

STS Congenital Database index operations (2014-2019) were included. Adjusted operative mortality in "past" 4- and 1-year intervals vs. the most recent year ("present") was evaluated using Bayesian hierarchical logistic regression with results presented as odds ratios (95% credible interval).

RESULTS

Among 115,699 operations (106 hospitals), overall present observed mortality was 2.5%. Regression to the mean was evident and individual hospital's present vs. past adjusted mortality were only weakly correlated (-0.11 vs. past 1-year, 0.22 vs. past 4-year data). There was a significant relationship between past and present mortality only for the group of hospitals in the highest mortality quartile, most prominent for past 4-year data [adjusted odds ratio vs. lowest mortality quartile 2.04 (1.44-2.80)]. The proportion of present hospital mortality variation explained by past mortality quartile was 52% (20%-90%) using past 4-year and only 27% (92%-83%) using past 1-year data. Overall 66% of hospitals changed mortality quartiles from past to present (30% by ≥2 quartiles).

CONCLUSIONS

Past mortality relates to present primarily for groups of hospitals at the extremes, with past 4-year more informative than past 1-year data. For individual hospitals, past may differ from present, regression to the mean is common, and many change quartiles. Past mortality should be used thoughtfully and not as the sole factor informing present decision making.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Tissue formation and host remodeling of an elastomeric biodegradable scaffold in an ovine pulmonary leaflet replacement model

In pursuit of a suitable scaffold material for cardiac valve tissue engineering applications, an acellular, electrospun, biodegradable polyester carbonate urethane urea (PECUU) scaffold was evaluated as a pulmonary valve leaflet replacement in vivo. In sheep (n = 8), a single pulmonary valve leaflet was replaced with a PECUU leaflet and followed for 1, 6, and 12 weeks. Implanted leaflet function was assessed in vivo by echocardiography. Explanted samples were studied for gross pathology, microscopic changes in the extracellular matrix, host cellular re-population, and immune responses, and for biomechanical properties. PECUU leaflets showed normal leaflet motion at implant, but decreased leaflet motion and dimensions at 6 weeks. The leaflets accumulated α-SMA and CD45 positive cells, with surfaces covered with endothelial cells (CD31+). New collagen formation occurred (Picrosirius Red). Accumulated tissue thickness correlated with the decrease in leaflet motion. The PECUU scaffolds had histologic evidence of scaffold degradation and an accumulation of pro-inflammatory/M1 and anti-inflammatory/M2 macrophages over time in vivo. The extent of inflammatory cell accumulation correlated with tissue formation and polymer degradation but was also associated with leaflet thickening and decreased leaflet motion. Future studies should explore pre-implant seeding of polymer scaffolds, more advanced polymer fabrication methods able to more closely approximate native tissue structure and function, and other techniques to control and balance the degradation of biomaterials and new tissue formation by modulation of the host immune response.

Growth of the Neo-Aortic Root and Prognosis of Transposition of the Great Arteries

BACKGROUND

Neo-aortic root dilatation can lead to significant late morbidity after the arterial switch operation (ASO) for dextro-transposition of the great arteries (d-TGA).

OBJECTIVES

We sought to examine the growth of the neo-aortic root in d-TGA.

METHODS

A single-center, retrospective cohort study of patients who underwent the ASO between July 1, 1981 and September 30, 2022 was performed. Morphology was categorized as dextro-transposition of the great arteries with intact ventricular septum (d-TGA-IVS), dextro-transposition of the great arteries with ventricular septal defect (d-TGA-VSD), and double-outlet right ventricle-transposition of the great arteries type (DORV-TGA). Echocardiographically determined diameters and derived z scores were measured at the annulus, sinus of Valsalva, and sinotubular junction immediately before the ASO and throughout follow-up. Trends in root dimensions over time were assessed using linear mixed-effects models. The association between intrinsic morphology and the composite of moderate-severe aortic regurgitation (AR) and neo-aortic valve or root intervention was evaluated with univariable and multivariable Cox proportional hazards models.

RESULTS

Of 1,359 patients who underwent the ASO, 593 (44%), 666 (49%), and 100 (7%) patients had d-TGA-IVS, d-TGA-VSD, and DORV-TGA, respectively. Each patient underwent a median of 5 echocardiograms (Q1-Q3: 3-10 echocardiograms) over a median follow-up of 8.6 years (range: 0.1-39.3 years). At 30 years, patients with DORV-TGA demonstrated greater annular (P < 0.001), sinus of Valsalva (P = 0.039), and sinotubular junction (P = 0.041) dilatation relative to patients with d-TGA-IVS. On multivariable analysis, intrinsic anatomy, older age at ASO, at least mild AR at baseline, and high-risk root dilatation were associated with moderate-severe AR and neo-aortic valve or root intervention at late follow-up (all P < 0.05).

CONCLUSIONS

Longitudinal surveillance of the neo-aortic root is warranted long after the ASO.

Burden with No Benefit: Prior Authorization in Congenital Cardiology

Prior authorization is a process that health insurance companies use to determine if a patient's health insurance will cover certain medical treatments, procedures, or medications. Prior authorization requests are common in adult congenital and pediatric cardiology (ACPC) due to need for advanced diagnostics, complex procedures, disease-specific medications, and the heterogeneity of the ACPC population. Prior authorizations in ACPC are rarely denied, but nonetheless, they are often accompanied by significant administrative burden on clinical care teams and delays in patient care. Prior authorizations have been implicated in worsening care inequities. The prior authorization process is insurer specific with differences between commercial and public insurers. Prior authorization rejections were previously found to be more common for women, racial minorities, those with low education, and in low-income groups. Prior authorization unduly burdens routine diagnostics, routine interventional and surgical procedures, and routine cardiac specific medication use in the ACPC population. This manuscript highlights the burdens of prior authorization and advocates for the elimination of prior authorization for ACPC patients.

Natural history of aortic root dilatation and pathologic aortic regurgitation in tetralogy of Fallot and its morphological variants

OBJECTIVE

We sought to characterize the natural history of aortic root dilatation and aortic regurgitation in tetralogy of Fallot (TOF).

METHODS

A single-center review of patients who underwent TOF repair from January 1960 to December 2022 was performed. Morphology was categorized as TOF-pulmonary stenosis or TOF-variant (including TOF-pulmonary atresia and TOF-pulmonary atresia-major aortopulmonary collateral arteries). Echocardiographically determined diameters and derived z scores were measured at the annulus, sinus of Valsalva, and sinotubular junction immediately before TOF repair and throughout follow-up. Linear mixed-effects models assessed trends in dimensions over time.

RESULTS

Of 2205 patients who underwent primary repair of TOF at a median age of 4.9 months (interquartile range, 2.3-20.5 months) and survived to discharge, 1608 (72.9%) patients had TOF-pulmonary stenosis and 597 (27.1%) patients had TOF-variant. At a median postoperative follow-up of 14.4 years (interquartile range, 3.3-27.6 years; range, 0.1-62.6 years), 313 (14.2%) patients had mild or greater aortic regurgitation and 34 (1.5%) patients required an aortic valve or root intervention. The overall mean rates of annular, sinus of Valsalva, and sinotubular junction growth were 0.5 ± 0.2, 0.6 ± 0.3, and 0.7 ± 0.5 mm/year, respectively. Root z scores remained stable with time. At baseline, patients with TOF-variant had larger diameters and z scores at the annulus, sinus of Valsalva, and sinotubular junction, compared with patients with TOF-pulmonary stenosis (all P values < .05). Over time, patients with TOF-variant demonstrated relatively greater annular (P = .020), sinus of Valsalva (P < .001), and sinotubular junction (P < .001) dilatation. Patients with ≥75th percentile root growth rates had a higher incidence of mild or greater aortic regurgitation (P < .001), moderate or greater aortic regurgitation (P < .001), and aortic valve repair or replacement (P = .045).

CONCLUSIONS

Patients with TOF-variant are at comparatively greater risk of pathologic root dilatation over time, warranting closer longitudinal follow-up.

Pentagalloyl glucose-stabilized decellularized bovine jugular vein valved conduits as pulmonary conduit replacement

Congenital heart diseases (CHD) are one of the most frequently diagnosed congenital disorders, affecting approximately 40,000 live births annually in the United States. Out of the new patients diagnosed with CHD yearly, an estimated 2,500 patients require a substitute, non-native conduit artery to replace structures congenitally absent or hypoplastic. Devices used for conduit replacement encounter limitations exhibiting varying degrees of stiffness, calcification, susceptibility to infection, thrombosis, and a lack of implant growth capacity. Here, we report the functionality of pentagalloyl glucose (PGG) stabilized decellularized valved bovine jugular vein conduit (PGG-DBJVC). The PGG-DBJVC tissues demonstrated mechanical properties comparable to native and glutaraldehyde fixed tissues, while exhibiting resistance to both collagenase and elastase enzymatic degradation. Subcutaneous implantation of tissues established their biocompatibility and resistance to calcification, while implantation in sheep in the pulmonary position demonstrated adequate implant functionality, and repopulation of host cells, without excessive inflammation. In conclusion, this PGG-DBJVC device could be a favorable replacement option for pediatric patients, reducing the need for reoperations required with current devices. STATEMENT OF SIGNIFICANCE: Congenital Heart Disease (CHD) is a common congenital disorder affecting many newborns in the United States each year. The use of substitute conduit arteries is necessary for some patients with CHD who have missing or underdeveloped structures. Current conduit replacement devices have limitations, including stiffness, susceptibility to infection and thrombosis, and lack of implant growth capacity. Pentagalloyl glucose-stabilized bovine jugular vein valved tissue (PGG-DBJVC) offers a promising solution as it is resistant to calcification, and biocompatible. When implanted in rats and as pulmonary conduit replacement in sheep, the PGG-DBJVC demonstrated cellular infiltration without excessive inflammation, which could lead to remodeling and integration with host tissue and eliminate the need for replacement as the child grows.

Natural History of Truncal Root Dilatation and Truncal Valve Regurgitation in Truncus Arteriosus

BACKGROUND

The natural history of the dilated truncal root in repaired truncus arteriosus (TA) is incompletely understood.

METHODS

A single-center review of patients who underwent TA repair between January 1984 and December 2018 was performed. Echocardiographically determined root diameters and derived z scores were measured at the annulus, sinus of Valsalva (SoV), and sinutubular junction (STJ) immediately before TA repair and throughout follow-up. Linear mixed-effects models assessed trends in root dimensions over time.

RESULTS

Of 193 patients who underwent TA repair at a median age of 12 days (interquartile range, 6-48 days) and survived to discharge, 34 (17.6%), 110 (57.0%), and 49 (25.4%) patients had bicuspid, tricuspid, and quadricuspid truncal valves, respectively. Median postoperative follow-up was 11.6 years (interquartile range, 4.4-22.0 years; range, 0.1-34.8 years). Truncal valve or root intervention was required in 38 patients (19.7%). The mean rates of annular, SoV, and STJ growth were 0.7 ± 0.3 mm/y, 0.8 ± 0.5 mm/y, and 0.9 ± 0.4 mm/y, respectively. Root z scores remained stable with time. At baseline, compared with patients with tricuspid leaflet anatomy, bicuspid patients had larger diameters at the SoV (P = .003) and STJ (P = .029), whereas quadricuspid patients had larger STJ diameters (P = .004). Over time, the bicuspid and quadricuspid cohorts demonstrated comparatively greater annular dilatation (both P < .05). Patients with ≥75th percentile root growth rates had a higher incidence of moderate-severe truncal regurgitation (P = .019) and truncal valve intervention (P = .002).

CONCLUSIONS

Root dilatation in TA persisted for up to 30 years after primary repair. Patients with bicuspid and quadricuspid truncal valves demonstrated greater root dilatation over time and required more valve interventions. Continued longitudinal follow-up is warranted in this higher-risk cohort.

The Society of Thoracic Surgeons Congenital Heart Surgery Database: 2022 Update on Outcomes and Research

The Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database continues to be one of the most comprehensive clinical outcomes registries capturing almost all pediatric cardiothoracic surgical operations undertaken in the United States. The latest analysis of aggregate outcomes was performed after the 33rd data harvest and included congenital and pediatric cardiac operations performed between July 1, 2017 and June 30, 2021. This article summarizes these contemporary outcomes and provides a context for the interpretation of these outcomes. In addition this article describes ongoing efforts to improve data collection and augment analytical approaches. Finally, research activities undertaken in the last year using data from the database are also summarized.

Variation in Case-Mix Across Hospitals: Analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database

BACKGROUND

The Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database was queried to document variation of patient characteristics, procedure types, and programmatic case-mix.

METHODS

All index cardiac operations in patients less than 18 years of age in the STS Congenital Heart Surgery Database (July 2016 to June 2020) were eligible for inclusion except patients weighing ≤2.5 kg undergoing isolated patent ductus arteriosus closure. At the hospital level, we describe variations in patient and procedural characteristics known from previous analyses to be associated with outcomes. We also report variations across hospitals of programmatic case-mix.

RESULTS

Data were analyzed from 117 sites (90 322 total operations, 87 296 total index cardiac operations eligible for STAT [STS-European Association for Cardio-Thoracic Surgery] 2020 Mortality Score). The median annual total index cardiac operations eligible for STAT 2020 Mortality Score per hospital was 157 (interquartile range [IQR], 94-276). Wide variability was documented in total annual index cardiac operations eligible for STAT 2020 Mortality Score per hospital (ratio 90th/10th percentile = 9.01), operations in neonates weighing <2.5 kg (ratio 90th/10th percentile = 4.09), operations in patients with noncardiac anatomic abnormalities (ratio 90th/10th percentile = 3.46), and operations in patients with preoperative mechanical ventilation (ratio 90th/10th percentile = 3.97). At the hospital level, the median percentage of all index cardiac operations in STAT 2020 Mortality Category 5 was 3.7% (IQR, 1.7%-4.9%), the median percentage of all index cardiac operations in STAT 2020 Mortality Category 4 or 5 was 24.4% (IQR, 19.0%-28.4%), the median hospital-specific mean STAT Mortality Category was 2.39 (IQR, 2.20-2.47), and the median hospital-specific mean STAT Mortality Score was 0.86 (IQR, 0.73-0.91).

CONCLUSIONS

Substantial variation of patient characteristics, procedure types, and case-mix exists across pediatric and congenital cardiac surgical programs. Knowledge about programmatic case-mix augments data about indirectly standardized programmatic observed-to-expected (O/E) mortality. Indirectly standardized O/E ratios do not provide a complete description of a given pediatric and congenital cardiac surgical program. The indirectly standardized programmatic O/E ratios associated with a given program apply only to its specific case-mix of patients and may represent a quite different case-mix than that of another program.

The Endangered State of Medicare Reimbursement for Cardiothoracic Surgery: A Call to Action

Reimbursement for cardiothoracic surgery continues to be threatened with enormous financial cuts, ranging from 5% to 10% in recent years. In this policy perspective, we describe the history of reimbursement for cardiothoracic surgery, highlight areas in need of urgent reform, propose possible solutions which Congress and the Executive Branch may enact, and call cardiothoracic surgeons to action on this critical issue. Meaningful engagement of STS members with their elected representatives is the only way to prevent these cuts.

Mortality Prediction Following Cardiac Surgery in Children - An STS Congenital Heart Surgery Database Analysis

BACKGROUND

The Society of Thoracic Surgeons' Congenital Heart Surgery Database (STS CHSD) provides risk-adjusted operative mortality rates to approximately 120 North American congenital heart centers. Optimal case-mix adjustment methods for operative mortality risk prediction in this population remain unclear.

METHODS

A panel created diagnosis-procedure (D-P) combinations of encounters in the CHSD. Models for operative mortality using the new D-P categories, procedure-specific risk factors, and syndromes/abnormalities included in the CHSD were estimated using Bayesian additive regression trees (BART) and lasso models. Performance of the new models was compared to the current STS-CHSD risk model.

RESULTS

Of 98,825 operative encounters (69,063 training; 29,762 testing), 2,818 (2.85%) STS-defined operative mortalities were observed. Differences in sensitivity, specificity, true and false positive predicted values were negligible across models. Calibration for mortality predictions at the higher end of risk from the lasso and BART models was better than predictions from the STS-CHSD model, likely due to new models' inclusion of diagnosis-palliative procedure variables affecting < 1% of patients overall, but accounting for 27% of mortalities. Model discrimination varied across models for high-risk procedures, hospital volume, and hospitals.

CONCLUSIONS

Overall performance of the new models did not differ meaningfully from the STS-CHSD risk model. Addition of procedure-specific risk factors and allowing diagnosis to modify predicted risk for palliative operations may augment model performance for very high-risk surgeries. Given the importance of risk adjustment in estimating hospital quality, a comparative assessment of surgical program quality evaluations using the different models is warranted.

Assessment of Current STS Data Elements for Adults with Congenital Heart Disease

BACKGROUND

To identify opportunities for enhanced ACHD data collection, a structured review of existing variables in the STS Congenital Heart Surgery Database (CHSD) and the STS Adult Cardiac Surgery Database (ACSD) was conducted.

METHODS

A working group was assembled representing multiple STS Workforces and Task Forces. The ACSD was reviewed systematically over eight 90 minute calls. ACSD version 4.20.2 and CHSD version 3.41 were used, and the ACSD was approached in sections. ACSD variables were classified as either: 1) represented in identical form in the CHSD (no further discussion), 2) represented in similar form in the CHSD (discussed for potential harmonization of definitions), or 3) not represented in the CHSD (discussed for potential inclusion). Variables felt to be relevant to ACHD were noted, and special consideration was given to STS required fields and variables utilized in existing STS adult risk models. Other factors that were examined were the frequency, utilization, and capture of existing ACSD variables.

RESULTS

Over 22 weeks (8 calls), the existing 1069 variables in version 4.20.2 of the ACSD were discussed. Ultimately, 539 total variables were found to be both 1) relevant to ACHD and 2) not currently collected in the CHSD. These were recommended for inclusion in the next CHSD upgrade for patients older than 18 years.

CONCLUSIONS

For adult patients having case records entered into the CHSD, the inclusion of a limited set of additional data fields from the ACSD should enhance capture of co-morbidities and other clinical data relevant to the ACHD population.

Left Pulmonary Artery Sling: Postoperative Outcomes for Patients at a Single Center

BACKGROUND

Left pulmonary artery (LPA) sling is a rare anomaly characterized by the origin of the LPA from the right pulmonary artery with a course between the trachea and esophagus. It is often associated with airway and cardiac anomalies.

METHODS

This is a retrospective case series of consecutive patients who underwent LPA sling repair (LPASR) at a tertiary care center over a 35-year period with a focus on tracheal and/or LPA reinterventions and survival.

RESULTS

Between June 1983 and July 2018, 42 patients were identified: isolated LPASR was performed in 16 (38%), LPASR/intracardiac repair in 10 (24%), and LPASR/tracheal repair in 16 (38%). There were 5 (12%) in-hospital and 4 (10%) late deaths. Survival rates (15 years) were as follows: 100% (isolated LPASR), 65% (concomitant intracardiac repair), and 52% (concomitant tracheal surgery). Preoperative intensive care unit (ICU) hospitalization was associated with future intervention on the LPA/trachea (61%, 11/18). The median distribution of blood flow to the left lung post-index surgery was 38%. Freedom from isolated LPA intervention was 100% after isolated LPASR, 93% after LPASR/tracheal surgery, and 69% after LPASR/intracardiac repair. Freedom from isolated tracheal intervention was 92% after isolated LPASR, 73% after LPASR/tracheal surgery, and 78% after LPASR/intracardiac repair.

CONCLUSIONS

ICU hospitalization prior to index surgery may indicate the severity of associated cardiac/tracheal abnormalities as this is associated with increased morbidity and mortality. Patients who underwent LPASR/intracardiac surgery were more likely to undergo isolated LPA intervention and those who underwent LPASR/tracheal surgery were more likely to undergo isolated tracheal intervention.

The Society of Thoracic Surgeons Congenital Heart Surgery Database: 2021 Update on Outcomes and Research

The Society of Thoracic Surgeons Congenital Heart Surgery Database is a comprehensive clinical outcomes registry that captures almost all pediatric cardiac surgical operations in the United States. It is the platform for all activities of The Society of Thoracic Surgeons related to the analysis of outcomes and improvement of quality in this subspecialty. This report summarizes current aggregate national outcomes in congenital and pediatric cardiac surgery performed between July 1, 2016, and June 30, 2020. The reported data on aggregate national outcomes are exemplified by an analysis of 10 prespecified benchmark operation groups performed. This report further reviews related activities in the areas of data collection and analysis, quality measurement, performance improvement, and research.

Histological changes after pulmonary artery banding for retraining of subpulmonary left ventricle

BACKGROUND

Patients with congenitally corrected transposition of the great arteries (ccTGA) with intact ventricular septum (IVS) or d-looped transposition of the great arteries (DTGA) with IVS post atrial switch operation often develop left ventricular dysfunction after anatomical repair despite prior retraining of the morphologically left ventricle (mLV) using pulmonary artery banding (PAB). We examined histopathological changes in such mLV.

METHODS

Capillary density, myocyte diameter, and interstitial fibrous area in the mLV were retrospectively evaluated in postmortem or explanted heart specimens obtained from patients with ccTGA/IVS or DTGA/IVS post atrial switch operation after PAB for retraining and compared with those of patients with normal cardiac anatomy, ccTGA/IVS or DTGA/IVS without PAB, and ccTGA or DTGA with high mLV pressure using generalized estimating equations models.

RESULTS

Adjusting for age, capillary density in four patients with ccTGA/IVS or DTGA/IVS after PAB was ∼20% lower than that in eight patients with normal cardiac anatomy (3149 ± 863 / um² vs 3978 ± 1206 /um² (mean, SD); p = 0.039), while myocyte diameter was ∼50% larger (16.2 ± 4.0 um vs 11.7 ± 2.4 um (mean, SD); p < 0.001). Interstitial fibrous area did not differ between the two groups (803 ± 422 um² vs 789 ± 480 um², p = 0.92).

CONCLUSIONS

We observed significant cardiomyocyte hypertrophy but lower capillary density in patients with ccTGA/IVS or DTGA/IVS after PAB for retraining compared to normal controls. This suggests inadequate capillary growth is a potential pathological basis for mLV dysfunction occurring after retraining or anatomical repair.

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.

Updating an Empirically Based Tool for Analyzing Congenital Heart Surgery Mortality

OBJECTIVES

STAT Mortality Categories (developed 2009) stratify congenital heart surgery procedures into groups of increasing mortality risk to characterize case mix of congenital heart surgery providers. This update of the STAT Mortality Score and Categories is empirically based for all procedures and reflects contemporary outcomes.

METHODS

Cardiovascular surgical operations in the Society of Thoracic Surgeons Congenital Heart Surgery Database (January 1, 2010 - June 30, 2017) were analyzed. In this STAT 2020 Update of the STAT Mortality Score and Categories, the risk associated with a specific combination of procedures was estimated under the assumption that risk is determined by the highest risk individual component procedure. Operations composed of multiple component procedures were eligible for unique STAT Scores when the statistically estimated mortality risk differed from that of the highest risk component procedure. Bayesian modeling accounted for small denominators. Risk estimates were rescaled to STAT 2020 Scores between 0.1 and 5.0. STAT 2020 Category assignment was designed to minimize within-category variation and maximize between-category variation.

RESULTS

Among 161,351 operations at 110 centers (19,090 distinct procedure combinations), 235 types of single or multiple component operations received unique STAT 2020 Scores. Assignment to Categories resulted in the following distribution: STAT 2020 Category 1 includes 59 procedure codes with model-based estimated mortality 0.2% to 1.3%; Category 2 includes 73 procedure codes with mortality estimates 1.4% to 2.9%; Category 3 includes 46 procedure codes with mortality estimates 3.0% to 6.8%; Category 4 includes 37 procedure codes with mortality estimates 6.9% to 13.0%; and Category 5 includes 17 procedure codes with mortality estimates 13.5% to 38.7%. The number of procedure codes with empirically derived Scores has grown by 58% (235 in STAT 2020 vs 148 in STAT 2009). Of the 148 procedure codes with empirically derived Scores in 2009, approximately one-half have changed STAT Category relative to 2009 metrics. The New STAT 2020 Scores and Categories demonstrated good discrimination for predicting mortality in an independent validation sample (July 1, 2017-June 30, 2019; sample size 46,933 operations at 108 centers) with C-statistic = 0.791 for STAT 2020 Score and 0.779 for STAT 2020 Category.

CONCLUSIONS

The updated STAT metrics reflect contemporary practice and outcomes. New empirically based STAT 2020 Scores and Category designations are assigned to a larger set of procedure codes, while accounting for risk associated with multiple component operations. Updating STAT metrics based on contemporary outcomes facilitates accurate assessment of case mix.

Long-term outcomes of truncus arteriosus repair: A modulated renewal competing risks analysis

OBJECTIVE

In this study, we sought to identify independent risk factors for mortality and reintervention after early surgical correction of truncus arteriosus using a novel statistical method.

METHODS

Patients undergoing neonatal/infant truncus arteriosus repair between January 1984 and December 2018 were reviewed retrospectively. An innovative statistical strategy was applied integrating competing risks analysis with modulated renewal for time-to-event modeling.

RESULTS

A total of 204 patients were included in the study. Mortality occurred in 32 patients (15%). Smaller right ventricle to pulmonary artery conduit size and truncal valve insufficiency at birth were significantly associated with overall mortality (right ventricle to pulmonary artery conduit size: hazard ratio, 1.34; 95% confidence interval, 1.08-1.66, P = .008; truncal valve insufficiency: hazard ratio, 2.5; 95% confidence interval, 1.13-5.53, P = .024). truncal valve insufficiency at birth, truncal valve intervention at index repair, and number of cusps (4 vs 3) were associated with truncal valve reoperations (truncal valve insufficiency: hazard ratio, 2.38; 95%, confidence interval, 1.13-5.01, P = .02; cusp number: hazard ratio, 6.62; 95% confidence interval, 2.54-17.3, P < .001). Right ventricle to pulmonary artery conduit size 11 mm or less was associated with a higher risk of early catheter-based reintervention (hazard ratio, 1.54; 95% confidence interval, 1.04-2.28, P = .03) and reoperation (hazard ratio, 1.96; 95% confidence interval, 1.33-2.89, P = .001) on the right ventricle to pulmonary artery conduit.

CONCLUSIONS

Smaller right ventricle to pulmonary artery conduit size and truncal valve insufficiency at birth were associated with overall mortality after truncus arteriosus repair. Quadricuspid truncal valve, the presence of truncal valve insufficiency at the time of diagnosis, and truncal valve intervention at index repair were associated with an increased risk of reoperation. The size of the right ventricle to pulmonary artery conduit at index surgery is the single most important factor for early reoperation and catheter-based reintervention on the conduit.

Management of Complex Left Ventricular Outflow Tract Obstruction: A Comparison of Konno and Modified Konno Techniques

Management of complex left ventricular outflow tract obstruction (LVOTO) can be achieved with a Konno or Modified Konno procedure to enlarge the LVOT. We hypothesized that patients who undergo a Modified Konno procedure would have a higher rate of LVOT re-intervention compared to the Konno procedure. Patients who underwent a Konno or Modified Konno procedure for LVOTO at a single tertiary care center between 1990 and 2014 were retrospectively reviewed. The primary outcome was LVOT re-intervention post-discharge from index Konno or Modified Konno procedure. Cox regression and Kaplan-Meier estimates were used for time-to-event analysis of LVOT re-interventions, any unplanned re-interventions, and transplant-free survival. The study included 122 patients: 51 (41.8%) in the Konno group and 71 (58.2%) in the Modified Konno group. Median age at surgery was 8.2 (IQR 3-16) years in the Konno group and 3.9 (IQR 1.5-11) years in the Modified Konno group. Multiple left heart lesions were less prevalent in Modified Konno patients. There were 36 (29.5%) patients with LVOT re-interventions: 8 (16%) in the Konno group and 28 (39.4%) in the Modified Konno group (p = 0.01). Transplant-free survival at five years was 87.2% for the Konno group and 93.5% for the Modified Konno group. A higher rate of LVOT re-intervention was found in the Modified Konno group although the Konno and Modified Konno techniques were applied to different patient populations. This finding suggests that careful preoperative decision-making can direct therapy appropriately and that fundamental diagnosis affects procedure choice.

Long-Term Fate of the Truncal Valve

Background Long-term survival in patients with truncus arteriosus is favorable, but there remains significant morbidity associated with ongoing reinterventions. We aimed to study the long-term outcomes of the truncal valve and identify risk factors associated with truncal valve intervention. Methods and Results We retrospectively reviewed patients who underwent initial truncus arteriosus repair at our institution from 1985 to 2016. Analysis was performed on the 148 patients who were discharged from the hospital and survived ≥30 days postoperatively using multivariable competing risks Cox regression modeling. Median follow-up time was 12.6 years (interquartile range, 5.0-22.1 years) after discharge from full repair. Thirty patients (20%) underwent at least one intervention on the truncal valve during follow-up. Survival at 1, 10, and 20 years was 93.1%, 87.0%, and 80.9%, respectively. The cumulative incidence of any truncal valve intervention by 20 years was 25.6%. Independent risk factors for truncal valve intervention included moderate or greater truncal valve regurgitation (hazard ratio [HR], 4.77; P<0.001) or stenosis (HR, 4.12; P<0.001) before full truncus arteriosus repair and moderate or greater truncal valve regurgitation at discharge after full repair (HR, 8.60; P<0.001). During follow-up, 33 of 134 patients (25%) progressed to moderate or greater truncal valve regurgitation. A larger truncal valve root z-score before truncus arteriosus full repair and during follow-up was associated with worsening truncal valve regurgitation. Conclusions Long-term rates of truncal valve intervention are significant. At least moderate initial truncal valve stenosis and initial or residual regurgitation are independent risk factors associated with truncal valve intervention. Larger truncal valve root z-score is associated with significant truncal valve regurgitation and may identify a subset of patients at risk for truncal valve dysfunction over time.

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.

De Novo Damaging Variants, Clinical Phenotypes, and Post-Operative Outcomes in Congenital Heart Disease

Supplemental Digital Content is available in the text.

Background:

De novo genic and copy number variants are enriched in patients with congenital heart disease, particularly those with extra-cardiac anomalies. The impact of de novo damaging variants on outcomes following cardiac repair is unknown.

Methods:

We studied 2517 patients with congenital heart disease who had undergone whole-exome sequencing as part of the CHD GENES study (Congenital Heart Disease Genetic Network).

Results:

Two hundred ninety-four patients (11.7%) had clinically significant de novo variants. Patients with de novo damaging variants were 2.4 times more likely to have extra-cardiac anomalies (P=5.63×10⁻¹²). In 1268 patients (50.4%) who had surgical data available and underwent open-heart surgery exclusive of heart transplantation as their first operation, we analyzed transplant-free survival following the first operation. Median follow-up was 2.65 years. De novo variants were associated with worse transplant-free survival (hazard ratio, 3.51; P=5.33×10⁻⁰⁴) and longer times to final extubation (hazard ratio, 0.74; P=0.005). As de novo variants had a significant interaction with extra-cardiac anomalies for transplant-free survival (P=0.003), de novo variants conveyed no additional risk for transplant-free survival for patients with these anomalies (adjusted hazard ratio, 1.96; P=0.06). By contrast, de novo variants in patients without extra-cardiac anomalies were associated with worse transplant-free survival during follow-up (hazard ratio, 11.21; P=1.61×10⁻⁰⁵) than that of patients with no de novo variants. Using agnostic machine-learning algorithms, we identified de novo copy number variants at 15q25.2 and 15q11.2 as being associated with worse transplant-free survival and 15q25.2, 22q11.21, and 3p25.2 as being associated with prolonged time to final extubation.

Conclusions:

In patients with congenital heart disease undergoing open-heart surgery, de novo variants were associated with worse transplant-free survival and longer times on the ventilator. De novo variants were most strongly associated with adverse outcomes among patients without extra-cardiac anomalies, suggesting a benefit for preoperative genetic testing even when genetic abnormalities are not suspected during routine clinical practice.

Registration:

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01196182.

Do Professionalism Lapses in Medical School Predict Problems in Residency and Clinical Practice?

PURPOSE

Recognizing that physicians must exhibit high levels of professionalism, researchers have attempted to identify the precursors of clinicians' professionalism difficulties, typically using retrospective designs that trace sanctioned physicians back to medical school. To better establish relative risk for professionalism lapses in practice, however, this relationship must also be studied prospectively. Therefore, this study investigated the sequelae of medical school professionalism lapses by following students with medical school professionalism problems into residency and practice.

METHOD

Beginning in 2014, 108 graduates from Harvard Medical School and Case Western Reserve University School of Medicine who appeared before their schools' review boards between 1993 and 2007 for professionalism-related reasons were identified, as well as 216 controls matched by sex, minority status, and graduation year. Prematriculation information and medical school performance data were collected for both groups. Outcomes for the groups were studied at 2 points in time: ratings by residency directors, and state medical board sanctions and malpractice suits during clinical practice.

RESULTS

Compared with controls, students who appeared before their schools' review boards were over 5 times more likely to undergo disciplinary review during residency (16% vs 3%, respectively) and almost 4 times more likely to require remediation or counseling (35% vs 9%, respectively). During clinical practice, 10% of those who had made review board appearances were sued or sanctioned vs 5% of controls. Logistic regression for these outcomes indicated, however, that professional lapses in medical school were not the only, or even the most important, predictor of problems in practice.

CONCLUSIONS

Students with professionalism lapses in medical school are significantly more likely to experience professionalism-related problems during residency and practice, although other factors may also play an important predictive role.

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.

Estimating Resource Utilization in Congenital Heart Surgery

BACKGROUND

Optimal methods to assess resource utilization in congenital heart surgery remain unclear. We compared traditional cost-to-charge ratio methods with newer standardized cost methods that aim to more directly assess resources consumed.

METHODS

Clinical data from The Society of Thoracic Surgeons Database were linked with resource use data from the Pediatric Health Information Systems Database (2010 to 2015). Standardized cost methods specific to the congenital heart surgery population were developed and compared with cost-to-charge ratio methods. Resource use in the overall population and variability across hospitals were described using hierarchical mixed effect models adjusting for case-mix.

RESULTS

Overall, 43 hospitals (65,331 patients) were included. There were minimal population-level differences in the distribution of resource use as estimated by the two methods. At the hospital level, there was less apparent variability in resource use across centers with the standardized cost vs cost-to-charge ratio method, overall (coefficient of variation 20% vs 25%) and across complexity (The Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery [STAT]) categories. When hospitals were categorized into tertiles by resource use, 33% changed classification depending on which resource use method was used (26% by one tertile and 7% by two tertiles).

CONCLUSIONS

In this first evaluation of standardized cost methodology in the congenital heart population, we found minimal differences vs traditional methods at the population level. At the hospital level, the magnitude of variation in resource use was less with standardized cost methods, and approximately one third of centers changed resource use categories depending on the methodology used. Because of these differences, care should be taken in future studies and in benchmarking and reporting efforts in selecting optimal methodology.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Society of Thoracic Surgeons Congenital Heart Surgery Database: 2019 Update on Research

As the largest congenital and pediatric cardiac surgical clinical data registry in the world, The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS CHSD) serves as a platform for reporting of outcomes and for quality improvement. In addition, it is an important source of data for clinical research and for innovations related to quality measurement. Each year, several teams of investigators undertake analyses of data in the STS CHSD pertaining to the surgical management of specific diagnostic and procedural groups, or to specific processes of care, and their associations with patient characteristics and outcomes across centers participating in the STS CHSD. Additional ongoing projects involve the development of new or refined metrics for quality measurement and reporting of outcomes and center-level performance. The STS, through its Workforce for National Databases and the STS Research Center and Workforce on Research Development provides multiple pathways through which investigators may propose and perform outcomes research projects based on STS CHSD data. This report reviews research published within the past year.

Autonomous Robotic Intracardiac Catheter Navigation Using Haptic Vision

While all minimally invasive procedures involve navigating from a small incision in the skin to the site of the intervention, it has not been previously demonstrated how this can be done autonomously. To show that autonomous navigation is possible, we investigated it in the hardest place to do it - inside the beating heart. We created a robotic catheter that can navigate through the blood-filled heart using wall-following algorithms inspired by positively thigmotactic animals. The catheter employs haptic vision, a hybrid sense using imaging for both touch-based surface identification and force sensing, to accomplish wall following inside the blood-filled heart. Through in vivo animal experiments, we demonstrate that the performance of an autonomously-controlled robotic catheter rivals that of an experienced clinician. Autonomous navigation is a fundamental capability on which more sophisticated levels of autonomy can be built, e.g., to perform a procedure. Similar to the role of automation in fighter aircraft, such capabilities can free the clinician to focus on the most critical aspects of the procedure while providing precise and repeatable tool motions independent of operator experience and fatigue.

Optically-guided instrument for transapical beating-heart delivery of artificial mitral chordae tendineae

OBJECTIVE

We sought to develop an instrument that would enable the delivery of artificial chordae tendineae (ACT) using optical visualization of the leaflet inside the beating heart.

METHODS

A delivery instrument was developed together with an ACT anchor system. The instrument incorporates an optically clear silicone grasping surface in which are embedded a camera and LED for direct leaflet visualization during localization, grasping, and chordal delivery. ACTs, comprised of T-shaped anchors and an expanded polytetrafluoroethylene chordae, were fabricated to enable testing in a porcine model. Ex vivo experiments were used to measure the anchor tear-out force from the mitral leaflets. In vivo experiments were performed in which the mitral leaflets were accessed transapically using only optical guidance and ACTs were deployed in the posterior and anterior leaflets (P2 and A2 segments).

RESULTS

In 5 porcine ex vivo experiments, the mean force required to tear the anchors from the leaflets was 3.8 ± 1.2 N. In 5 porcine in vivo nonsurvival procedures, 14 ACTs were successfully placed in the leaflets (9 in P2 and 5 in A2). ACT implantation took an average of 3.22 ± 0.83 minutes from entry to exit through the apex.

CONCLUSIONS

Optical visualization of the mitral leaflet during chordal placement is feasible and provides direct feedback to the operator throughout the deployment sequence. This enables visual confirmation of the targeted leaflet location, distance from the free edge, and successful deployment of the chordal anchor. Further studies are needed to refine and assess the device for clinical use.

Perioperatively Inhaled Hydrogen Gas Diminishes Neurologic Injury Following Experimental Circulatory Arrest in Swine

This study used a swine model of mildly hypothermic prolonged circulatory arrest and found that the addition of 2.4% inhaled hydrogen gas to inspiratory gases during and after the ischemic insult significantly decreased neurologic and renal injury compared with controls. With proper precautions, inhalational hydrogen may be administered safely through conventional ventilators and may represent a complementary therapy that can be easily incorporated into current workflows. In the future, inhaled hydrogen may diminish the sequelae of ischemia that occurs in congenital heart surgery, cardiac arrest, extracorporeal life-support events, acute myocardial infarction, stroke, and organ transplantation.

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

BACKGROUND

We describe the statistical methods and results related to development of the first congenital heart surgery composite quality measure.

METHODS

The composite measure was developed using The Society of Thoracic Surgeons Congenital Heart Surgery Database (2012 to 2015), Bayesian hierarchical modeling, and the current Society of Thoracic Surgeons risk model for case-mix adjustment. It consists of a mortality domain (operative mortality) and morbidity domain (major complications and postoperative length of stay). We evaluated several potential weighting schemes and properties of the final composite measure, including reliability (signal-to-noise ratio) and hospital classification in various performance categories.

RESULTS

Overall, 100 hospitals (78,425 operations) were included. Each adjusted metric included in the composite varied across hospitals: operative mortality (median, 3.1%; 10th to 90th percentile, 2.1% to 4.4%) major complications (median 11.7%, 10th to 90th percentile, 6.4% to 17.4%), and length of stay (median, 7.0 days; 10th to 90th percentile, 5.9 to 8.2 days). In the final composite weighting scheme selected, mortality had the greatest influence, followed by major complications and length of stay (correlation with overall composite score of 0.87, 0.69, and 0.47, respectively). Reliability of the composite measure was 0.73 compared with 0.59 for mortality alone. The distribution of hospitals across composite measure performance categories (defined by whether the 95% credible interval overlapped The Society of Thoracic Surgeons average) was 75% (same as expected), 9% (worse than expected), and 16% (better than expected).

CONCLUSIONS

This congenital heart surgery composite measure incorporates aspects of both morbidity and mortality, has clinical face validity, and greater ability to discriminate hospital performance compared with mortality alone. Ongoing efforts will support the use of the composite measure in benchmarking and quality improvement activities.

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.