Amelia S. Wallace

Perioperative mechanical circulatory support in children: An analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

OBJECTIVES Analyses of mechanical circulatory support (MCS) in pediatric heart surgery have primarily focused on single-center outcomes or narrow applications. We describe the patterns of use, patient characteristics, and MCS-associated outcomes across a large multicenter cohort. METHODS Patients (aged <18 years) in the Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (2000-2010) were included. The characteristics and outcomes of those receiving postoperative MCS were described, and bayesian hierarchical models were used to examine variations in the adjusted MCS rates across institutions. RESULTS Of 96,596 operations (80 centers), MCS was used in 2.4%. The MCS patients were younger (13 vs 195 days, P < .0001) and more often had STS-defined preoperative risk factors (57.2% vs 32.7%, P < .0001). The operations with the greatest MCS rates included the Norwood procedure (17%) and complex biventricular repairs (arterial switch, ventricular septal defect, and arch repair [14%]). More than one half of the MCS patients did not survive to hospital discharge (53.2% vs 2.9% of non-MCS patients; P < .0001). MCS-associated mortality was greatest for truncus arteriosus and Ross-Konno operations (both 71%). The hospital-level MCS rates adjusted for patient characteristics and case mix varied by 15-fold across institutions, with both high- and low-volume hospitals having substantial variation in MCS rates. CONCLUSIONS Perioperative MCS use varied widely across centers. The MCS rates were greatest overall for the Norwood procedure and complex biventricular repairs. Although MCS can be a life-saving therapy, more than one half of MCS patients will not survive to hospital discharge, with mortality >70% for some operations. Future studies aimed at better understanding the appropriate indications, optimal timing, and management of MCS could help to reduce the variation in MCS use across hospitals and improve outcomes.

Benchmark Outcomes for Pulmonary Valve Replacement Using The Society of Thoracic Surgeons Databases

BACKGROUND As less invasive alternatives to surgical pulmonary valve replacement (PVR) are being refined and evaluated, there is a need for benchmark data concerning outcomes from surgical PVR. METHODS We examined in-hospital outcomes from surgical PVR in The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) and Adult Cardiac Surgery Database (STS-ACSD) between 2007 and 2013, with a focus on patients likely to be eligible for transcatheter PVR (ie, ≥ 5 years age and ≥ 30 kg). Patient characteristics, morbidity, and mortality were described. RESULTS The STS-CHSD included 6,431 eligible patients with a median age of 17 years (interquartile range [IQR], 14-25 years). Preoperative comorbidities were uncommon: arrhythmia (1.7%), renal failure (0.1%), endocarditis (0.3%), neurologic deficit (0.8%), and diabetes (0.5%). In-hospital mortality was 0.9%. A major complication occurred in 2.2%. The STS-ACSD included 3,352 eligible patients; the median age was 41 years (IQR, 30-55 years). Preoperative comorbidities were more common: arrhythmia (24.3%), renal failure (3.8%), endocarditis (12.2%), cerebrovascular disease (7.9%), and diabetes (10.9%). In-hospital mortality was 4.1%. A major complication occurred in 20.9%. CONCLUSIONS Contemporary outcomes from surgical PVR include a low risk of in-hospital death or major complications. Patients in the STS-ACSD are older and have an increased prevalence of preoperative factors, which may contribute to higher morbidity and mortality.

Current Spectrum of Surgical Procedures Performed for Ebstein's Malformation: An Analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database

BACKGROUND Ebsteins malformation is a rare congenital cardiac anomaly. Available data are limited to individual reports demonstrating highly variable approaches. We sought to understand the spectrum of surgical treatment of Ebsteins anomaly across institutions. METHODS A retrospective review of surgical procedures performed on patients with primary diagnosis of Ebsteins malformation (2002 through 2009) in The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) was conducted. RESULTS A total of 595 operations on 498 patients with Ebsteins anomaly were included: 116 on neonates (19%), 122 on infants (21%), 264 on children (44%), and 93 on adults (16%). Average annual institutional case volumes were low (median, 1 per year; range, 0 to 8 per year). Neonates had a high rate of palliative procedures: systemic-to-pulmonary artery shunts with or without tricuspid valve closure (43; 37.1%) and tricuspid valve closure (10; 8.6%); Ebsteins repair or tricuspid valvuloplasty was performed in 32%. The most common procedures among infants were superior cavopulmonary connections (62; 50.8%) and systemic-to-pulmonary shunt (10; 8.2%). Among older patients, procedures were primarily in three categories: tricuspid valve surgery (children, 54.5%; adults, 68.8%), arrhythmia procedures (children, 8.7%; adults, 17.3%), and Fontan (children, 14.8%). In-hospital mortality was high in neonatal patients (23.4%) in comparison with infants (4.1%), children (0.7%), and adults (1.1%). CONCLUSIONS Surgery for Ebsteins anomaly consists of a wide range of procedures, with low individual institutional volumes. Mortality is highest among neonates. A prospective multicenter inception cohort study would be valuable to better define indications for specific strategies of surgical management.

Adverse cardiac events in children with Williams syndrome undergoing cardiovascular surgery: An analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

OBJECTIVE Patients with Williams syndrome (WS) undergoing cardiac surgery are at risk for major adverse cardiac events (MACE). Prevalence and risk factors for such events have not been well described. We sought to define frequency and risk of MACE in patients with WS using a multicenter clinical registry. METHODS We identified cardiac operations performed in patients with WS using the Society of Thoracic Surgeons Congenital Heart Surgery Database (2000-2012). Operations were divided into 4 groups: isolated supravalvular aortic stenosis, complex left ventricular outflow tract (LVOT), isolated right ventricular outflow tract (RVOT), and combined LVOT/RVOT procedures. The proportion of patients with MACE (in-hospital mortality, cardiac arrest, or postoperative mechanical circulatory support) was described and the association with preoperative factors was examined. RESULTS Of 447 index operations (87 centers), median (interquartile range) age and weight at surgery were 2.4 years (0.6-7.4 years) and 10.6 kg (6.5-21.5 kg), respectively. Mortality occurred in 20 patients (5%). MACE occurred in 41 patients (9%), most commonly after combined LVOT/RVOT (18 out of 87; 21%) and complex LVOT (12 out of 131; 9%) procedures, but not after isolated RVOT procedures. Odds of MACE decreased with age (odds ratio [OR], 0.99; 95% confidence interval [CI], 0.98-0.99), weight (OR, 0.97; 95% CI, 0.93-0.99), but increased in the presence of any preoperative risk factor (OR, 2.08; 95% CI, 1.06-4.00), and in procedures involving coronary artery repair (OR, 5.37; 95% CI, 2.05-14.06). CONCLUSIONS In this multicenter analysis, MACE occurred in 9% of patients with WS undergoing cardiac surgery. Demographic and operative characteristics were associated with risk. Further study is needed to elucidate mechanisms of MACE in this high-risk population.

Worldwide Trends in Multi-arterial Coronary Artery Bypass Grafting Surgery 2004-2014: A Tale of 2 Continents

Recent evidence shows that multi-arterial coronary artery bypass grafting (MABG) based on bilateral internal thoracic (BITA) or left internal thoracic (LITA) and radial artery (RA) improves long-term outcomes compared with single arterial coronary artery bypass grafting (SABG) (LITA + saphenous vein graft). How this evidence affected the worldwide use of MABG, if at all, is not well defined. Accordingly, we report 10-year temporal trends of MABG utilization from 2 continents. A study population of 1,683,434 non-emergent, primary, isolated LITA-based coronary artery bypass grafting (CABG) (≥2 grafts) patients was derived from the Society of Thoracic Surgeons (STS) (1,307,528 (79.5%) of 1,644,388 isolated CABG; total 1179 centers) and the Australia New Zealand Cardiothoracic (ANZ) Databases (34,213 (87%) of 39,046 isolated CABG; 24 centers) between 2004 and 2014. Patients were excluded based on the following: (1) no LITA, (2) if arterial grafts were other than RA or ITA, or (3) if grafting data were missing. The 3 MABG groups were LITA + RA, BITA, and BITA + RA, each with or without supplemental vein grafts. Grafting trends and their associated patient demographics were analyzed. SABG (89.3% STS, 51.4% ANZ) was the most common grafting strategy. MABG was most frequently accomplished by LITA + RA: (STS: 6.1%; ANZ: 42.6%), followed by BITA: (STS: 4.1%; ANZ: 4.3%), while ≥3 (BITA + RA) was rare in the STS (0.5%), but more common in ANZ (5.9%). In the STS, between 2004 and 2014, SABG rates systematically increased from 85.2% to 91.7%, BITA grafting was essentially unchanged from 3.6% to 4.3%, while RA use decreased systematically from 10.5% to 3.7%. In the ANZ, SABG rates increased from 17.3% to 51.4%, BITA grafting decreased from 6.3% to 3.6%, while RA grafting decreased from 65.8% to 39.0%. Compared with SABG patients, BITA patients were younger (STS: median age 59 vs 66, P < 0.001; ANZ: mean age 62 vs 68, P < 0.001), predominately male (STS: 84% vs 73%, P < 0.001; ANZ: 86% vs 79%, P < 0.001), less obese (body mass index >30 kg/m2) in STS (37% vs 42%, P < 0.001), more obese in ANZ (33% vs 32%, P = 0.001), and less diabetic (STS: 26% vs 43%, P < 0.001; ANZ: 25% vs 37%, P < 0.001), whereas RA patients were intermediate in age (STS: 61; ANZ: 65), in male sex (STS: 82%; ANZ: 81%), in the prevalence of diabetes (STS: 40%; ANZ: 34%), and were most obese (STS: 47%; ANZ: 34%). A decade-long analysis of STS data reveals a counterintuitive decline in the use (driven by decreasing RA use) of MABG: a potentially superior grafting strategy compared with SABG. In contra distinction, the smaller but growing ANZ data document a distinctly different CABG practice pattern, with a higher MABG utilization rate, but a similarly declining RA use. The reasons for these practice patterns and declining MABG are likely diverse and require further assessment.

Sources of Variation in Hospital-Level Infection Rates After Coronary Artery Bypass Grafting: An Analysis of The Society of Thoracic Surgeons Adult Heart Surgery Database

BACKGROUND Patients undergoing coronary artery bypass grafting (CABG) are at risk for a variety of infections. Investigators have focused on predictors of these adverse sequelae, but less attention has been focused on characterizing hospital-level variability in these outcomes. METHODS Between July 2011 and December 2013, The Society of Thoracic Surgeons Adult Cardiac Surgery Database shows 365,686 patients underwent isolated CABG in 1,084 hospitals. Hospital-acquired infections (HAIs) were defined as pneumonia, sepsis/septicemia, deep sternal wound infection/mediastinitis, vein harvest/cannulation site infection, or thoracotomy infection. Hospitals were ranked by their HAI rate as low (≤ 10th percentile), medium (10th to 90th percentile), and high (>90th percentile). Differences in perioperative factors and composite morbidity and mortality end points across these groups were determined using the Wilcoxon rank sum and χ(2) tests. RESULTS HAIs occurred among 3.97% of patients overall, but rates varied across hospital groups (low: <0.84%, medium: 0.84% to 8.41%, high: >8.41%). Pneumonia (2.98%) was the most common HAI, followed by sepsis/septicemia (0.84%). Patients at high-rate hospitals more often smoked, had diabetes, chronic lung disease, New York Heart Association Functional Classification III to IV, and received blood products (p < 0.001); however, they less often were prescribed the appropriate antibiotics (p < 0.001). Major morbidity and mortality occurred among 12.3% of patients, although this varied by hospital group (low: 8.6%, medium: 12.3%, high: 17.9%; p < 0.001). CONCLUSIONS Substantial hospital-level variation exists in postoperative HAIs among patients undergoing CABG, driven predominantly by pneumonia. Given the relatively small absolute differences in comorbidities across hospital groups, our findings suggest factors other than case mix may explain the observed variation in HAI rates.

Variation in Perfusion Strategies for Neonatal and Infant Aortic Arch Repair Contemporary Practice in the STS Congenital Heart Surgery Database

Background: Regional cerebral perfusion (RCP) is used as an adjunct or alternative to deep hypothermic circulatory arrest (DHCA) for neonates and infants undergoing aortic arch repair. Clinical studies have not demonstrated clear superiority of either strategy, and multicenter data regarding current use of these strategies are lacking. We sought to describe the variability in contemporary practice patterns for use of these techniques. Methods: The Society of Thoracic Surgeons Congenital Heart Surgery Database (2010-2013) was queried to identify neonates and infants whose index operation involved aortic arch repair with cardiopulmonary bypass. Perfusion strategy was classified as isolated DHCA, RCP (with less than or equal to ten minutes of DHCA), or mixed (RCP with more than ten minutes of DHCA). Data were analyzed for the entire cohort and stratified by operation subgroups. Results: Overall, 4,523 patients (105 centers) were identified; median age seven days (interquartile range: 5.0-13.0). The most prevalent perfusion strategy was RCP (43%). Deep hypothermic circulatory arrest and mixed perfusion accounted for 32% and 16% of cases, respectively. In all, 59% of operations involved some period of RCP. Regional cerebral perfusion was the most prevalent perfusion strategy for each operation subgroup. Neither age nor weight was associated with perfusion strategy, but reoperations were less likely to use RCP (31% vs 45%, P < .001). The combined duration of RCP and DHCA in the RCP group was longer than the DHCA time in the DHCA group (45 vs 36 minutes, P < .001). Conclusion: There is considerable variability in practice regarding perfusion strategies for arch repair in neonates and infants. In contemporary practice, RCP is the most prevalent perfusion strategy for these procedures. Use of DHCA is also common. Further investigation is warranted to ascertain possible relative merits of the various perfusion techniques.

Association of Surgeon Age and Experience with Congenital Heart Surgery Outcomes

Background— Surgeon experience concerns both families of children with congenital heart disease and medical providers. Relationships between surgeon seniority and patient outcomes are often assumed, yet there are little data. Methods and Results— This national study used linked data from the American Medical Association Physician Masterfile and the Society of Thoracic Surgeons-Congenital Heart Surgery Database to examine associations between surgeon years since medical school and major morbidity/mortality for children undergoing cardiac surgery. Sensitivity analyses explored the effects of patient characteristics, institutional/surgeon volumes, and various measures of institutional surgeon team experience. In secondary analyses, major morbidity and mortality were examined as separate end points. We identified 206 congenital heart surgeons from 91 centers performing 62 851 index operations (2010–2014). Median time from school was 25 years (range 9–55 years). A major morbidity/mortality occurred in 11.5% of cases. In multivariable analyses, the odds of major morbidity/mortality were similar for early-career (<15 years from medical school, ≈<40 years old), midcareer (15–24 years, ≈40–50 years old), and senior surgeons (25–35 years, ≈50–60 years old). The odds of major morbidity/mortality were ≈25% higher for operations performed by very senior surgeons (35–55 years from school, ≈60–80 years old; n=9044 cases). Results were driven by differences in morbidity. In extensive sensitivity analyses, these effects remained constant. Conclusions— In this study of >200 congenital heart surgeons, we found patient outcomes for surgeons with the fewest years of experience to be comparable to those of their midcareer and senior colleagues, within the context of existing referral and support practices. Very senior surgeons had higher risk-adjusted odds of major morbidity/mortality. Contemporary approaches to training, referral, mentoring, surgical planning, and other support practices might contribute to the observed outcomes of junior congenital heart surgeons being comparable to those of more experienced colleagues. Understanding and disseminating these practices might benefit the medical community at large.

Hypothermia and operative mortality during on-pump coronary artery bypass grafting

OBJECTIVE Controversy surrounds the effect of hypothermia on operative mortality during cardiac surgery. The present study accessed a large clinical database of coronary artery bypass graft operations to address the issue. METHODS A retrospective review of the Society of Thoracic Surgeons Adult Cardiac Surgery Database identified patients treated with isolated, nonemergency, on-pump coronary artery bypass grafting from July 2011 to December 2012. The patients were divided into 3 groups according to their lowest core temperature during the procedure: moderate hypothermia (≤ 34 °C), mild hypothermia (>34 °C but ≤ 36 °C), and normothermia (>36 °C). The primary endpoint of the study was operative mortality, defined according to the Database criteria. RESULTS During the study period, 142,541 patients were available for analysis; 94,777 (66.5%) received moderate hypothermia, 42,750 (30.3%) mild hypothermia, and 5014 (3.5%) normothermia. Operative mortality occurred in 1394 patients (1.5%) in the moderate hypothermia, 534 (1.3%) in the mild hypothermia, and 105 (2.1%) in the normothermia group. Multivariate analysis identified hypothermia (both mild [odds ratio, 0.66; 95% confidence interval, 0.54-0.81; P < .0001] and moderate [odds ratio, 0.73; 95% confidence interval, 0.60-0.89; P = .0015]) was protective against operative mortality compared with normothermia. No incremental benefit was noted between the different hypothermia grades (P = .0827). CONCLUSIONS Most patients receive hypothermia during on-pump coronary artery bypass grafting. Hypothermia is protective against operative mortality compared with normothermia in such patients. Moderate hypothermia does not provide additional survival benefit.

The Prevalence and Impact of Congenital Diaphragmatic Hernia among Patients Undergoing Surgery for Congenital Heart Disease

There has not been a multicenter investigation to elucidate the prevalence and impact of congenital diaphragmatic hernia (CDH) on children undergoing cardiac surgery. We investigated the prevalence of CDH across congenital cardiac diagnostic and procedural groups and its impact on outcomes. The STS Congenital Heart Surgery Database was queried to identify children undergoing cardiac surgery who also had CDH. Baseline perioperative characteristics and postoperative outcomes were compared between groups. Subgroup analyses were performed based on case complexity as determined by STAT Categories. Overall 426 of 157,419 (0.27%) pediatric patients undergoing an index cardiac operation had a diagnosis of CDH including 89 neonates (0.25% of all neonatal index operations), 217 infants (0.39%), and 120 children (0.18%). The frequency of concomitant CDH varied across diagnostic groups and, in neonates and infants, was highest for tetralogy of Fallot (0.45%, n = 41), coarctation (0.39%, n = 27) and complete atrioventricular septal defects (0.31%, n = 19). For neonates and infants outcomes were generally worse in CDH vs no-CDH patients across the various procedural strata. For example, STAT ≥3 operative mortality was 34.4% vs 10.3% ( P < 0.001) for neonates, and 24.2% vs 5.3% ( P < 0.001) for infants with vs without CDH, respectively. In older children, outcomes disparities were less clear cut with no significant differences in mortality, and variable differences for complication and length of stay outcomes. CDH occurs in a small percentage of patients born with congenital heart disease. Concomitant diagnosis of CDH portends increased morbidity and mortality in infants and neonates undergoing cardiac surgery.